id stringlengths 9 13 | submitter stringlengths 1 64 ⌀ | authors stringlengths 5 22.9k | title stringlengths 4 245 | comments stringlengths 1 548 ⌀ | journal-ref stringlengths 4 362 ⌀ | doi stringlengths 12 82 ⌀ | report-no stringlengths 2 281 ⌀ | categories stringclasses 793 values | license stringclasses 9 values | orig_abstract stringlengths 24 1.95k | versions listlengths 1 30 | update_date stringlengths 10 10 | authors_parsed listlengths 1 1.74k | abstract stringlengths 21 1.95k |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
2301.02914 | Mikhail Zubkov Dr | M. Selch, J. Miller, M.A.Zubkov | Gravastar-like black hole solutions in $q$-theory | Latex, 14 figures, 28 pages | null | 10.1088/1361-6382/ace14b | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present a stationary spherically symmetric solution of the Einstein
equations, with a source generated by a scalar field of $q$-theory. In this
theory Riemannian gravity, as described by the Einstein - Hilbert action, is
coupled to a three - form field that describes the dynamical vacuum. Formally
it behaves like a matter field with its own stress - energy tensor, equivalent
to a scalar field minimally coupled to gravity. The asymptotically flat
solutions obtained to the field equations represent black holes. For a
sufficiently large horizon radius the energy density is localized within a thin
spherical shell situated just outside of the horizon, analogous to a gravastar.
The resulting solutions to the field equations, which admit this class of
configurations, satisfy existence conditions that stem from the Black Hole no -
hair theorem, thanks to the presence of a region in space in which the energy
density is negative.
| [
{
"created": "Sat, 7 Jan 2023 18:32:20 GMT",
"version": "v1"
},
{
"created": "Tue, 30 May 2023 17:38:15 GMT",
"version": "v2"
}
] | 2023-07-26 | [
[
"Selch",
"M.",
""
],
[
"Miller",
"J.",
""
],
[
"Zubkov",
"M. A.",
""
]
] | We present a stationary spherically symmetric solution of the Einstein equations, with a source generated by a scalar field of $q$-theory. In this theory Riemannian gravity, as described by the Einstein - Hilbert action, is coupled to a three - form field that describes the dynamical vacuum. Formally it behaves like a matter field with its own stress - energy tensor, equivalent to a scalar field minimally coupled to gravity. The asymptotically flat solutions obtained to the field equations represent black holes. For a sufficiently large horizon radius the energy density is localized within a thin spherical shell situated just outside of the horizon, analogous to a gravastar. The resulting solutions to the field equations, which admit this class of configurations, satisfy existence conditions that stem from the Black Hole no - hair theorem, thanks to the presence of a region in space in which the energy density is negative. |
1603.01465 | Hooman Moradpour Hooman | H. Moradpour, Rafael C. Nunes, Everton M. C. Abreu, Jorge Ananias Neto | A note on the relations between thermodynamics, energy definitions and
Friedmann equations | The text has been increased | Mod. Phys. Lett. A (2017), Vol. 32, No. 13, 1750078 | 10.1142/S021773231750078X | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In what follows, we investigate the relation between the Friedmann and
thermodynamic pressure equations, through solving the Friedmann and
thermodynamic pressure equations simultaneously. Our investigation shows that a
perfect fluid, as a suitable solution for the Friedmann equations leading to
the standard modelling of the universe expansion history, cannot simultaneously
satisfy the thermodynamic pressure equation and those of Friedmann. Moreover,
we consider various energy definitions, such as the Komar mass, and solve the
Friedmann and thermodynamic pressure equations simultaneously to get some
models for dark energy. The cosmological consequences of obtained solutions are
also addressed. Our results indicate that some of obtained solutions may unify
the dominated fluid in both the primary inflationary and current accelerating
eras into one model. In addition, by taking into account a cosmic fluid of a
known equation of state, and combining it with the Friedmann and thermodynamic
pressure equations, we obtain the corresponding energy of these cosmic fluids
and face their limitations. Finally, we point out the cosmological features of
this cosmic fluid and also study its observational constraints.
| [
{
"created": "Mon, 29 Feb 2016 09:37:28 GMT",
"version": "v1"
},
{
"created": "Tue, 17 May 2016 05:58:30 GMT",
"version": "v2"
},
{
"created": "Sat, 6 Aug 2016 12:08:40 GMT",
"version": "v3"
}
] | 2017-04-21 | [
[
"Moradpour",
"H.",
""
],
[
"Nunes",
"Rafael C.",
""
],
[
"Abreu",
"Everton M. C.",
""
],
[
"Neto",
"Jorge Ananias",
""
]
] | In what follows, we investigate the relation between the Friedmann and thermodynamic pressure equations, through solving the Friedmann and thermodynamic pressure equations simultaneously. Our investigation shows that a perfect fluid, as a suitable solution for the Friedmann equations leading to the standard modelling of the universe expansion history, cannot simultaneously satisfy the thermodynamic pressure equation and those of Friedmann. Moreover, we consider various energy definitions, such as the Komar mass, and solve the Friedmann and thermodynamic pressure equations simultaneously to get some models for dark energy. The cosmological consequences of obtained solutions are also addressed. Our results indicate that some of obtained solutions may unify the dominated fluid in both the primary inflationary and current accelerating eras into one model. In addition, by taking into account a cosmic fluid of a known equation of state, and combining it with the Friedmann and thermodynamic pressure equations, we obtain the corresponding energy of these cosmic fluids and face their limitations. Finally, we point out the cosmological features of this cosmic fluid and also study its observational constraints. |
0903.3088 | Xin-Zhou Li | Xin-zhou Li, Chang-bo Sun and Ping Xi | Torsion cosmological dynamics | 4 pages, 3 figures | Phys.Rev.D79:027301,2009 | 10.1103/PhysRevD.79.027301 | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this paper, the dynamical attractor and heteroclinic orbit have been
employed to make the late-time behaviors of the model insensitive to the
initial condition and thus alleviate the fine-tuning problem in the torsion
cosmology. The late-time de Sitter attractor indicates that torsion cosmology
is an elegant scheme and the scalar torsion mode is an interesting geometric
quantity for physics. The numerical solutions obtained by Nester et al. are not
periodic solutions, but are quasi-periodic solutions near the focus for the
coupled nonlinear equations.
| [
{
"created": "Wed, 18 Mar 2009 04:47:48 GMT",
"version": "v1"
}
] | 2010-04-22 | [
[
"Li",
"Xin-zhou",
""
],
[
"Sun",
"Chang-bo",
""
],
[
"Xi",
"Ping",
""
]
] | In this paper, the dynamical attractor and heteroclinic orbit have been employed to make the late-time behaviors of the model insensitive to the initial condition and thus alleviate the fine-tuning problem in the torsion cosmology. The late-time de Sitter attractor indicates that torsion cosmology is an elegant scheme and the scalar torsion mode is an interesting geometric quantity for physics. The numerical solutions obtained by Nester et al. are not periodic solutions, but are quasi-periodic solutions near the focus for the coupled nonlinear equations. |
1402.5678 | Hoda Farahani | M. Khurshudyan, J. Sadeghi, A. Pasqua, S. Chattopadhyay, R.
Myrzakulov, and H. Farahani | Interacting Ricci dark energy models with an effective $\Lambda$-term in
Lyra manifold | 14 pages | IJTP 54 (2015) 749 | 10.1007/s10773-014-2266-7 | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this paper we consider a universe filled with barotropic dark matter and
Ricci dark energy in Lyra geometry with varying Lambda. We assume two different
kinds of interactions between dark matter and dark energy. Then, by using
numerical analysis, we investigate some cosmological parameters of the models
such as equation of state, Hubble and deceleration parameters.
| [
{
"created": "Sun, 23 Feb 2014 21:28:30 GMT",
"version": "v1"
}
] | 2015-05-12 | [
[
"Khurshudyan",
"M.",
""
],
[
"Sadeghi",
"J.",
""
],
[
"Pasqua",
"A.",
""
],
[
"Chattopadhyay",
"S.",
""
],
[
"Myrzakulov",
"R.",
""
],
[
"Farahani",
"H.",
""
]
] | In this paper we consider a universe filled with barotropic dark matter and Ricci dark energy in Lyra geometry with varying Lambda. We assume two different kinds of interactions between dark matter and dark energy. Then, by using numerical analysis, we investigate some cosmological parameters of the models such as equation of state, Hubble and deceleration parameters. |
1010.1143 | Mir Faizal | Mir Faizal | BRST and Anti-BRST Symmetries in Perturbative Quantum Gravity | Aversion accepted for publication in Foundations of Physics | Found.Phys.41:270-277,2011 | 10.1007/s10701-010-9511-6 | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In perturbative quantum gravity, the sum of the classical Lagrangian density,
a gauge fixing term and a ghost term is invariant under two sets of
supersymmetric transformations called the BRST and the anti-BRST
transformations. In this paper we will analyse the BRST and the anti-BRST
symmetries of perturbative quantum gravity in curved spacetime, in linear as
well as non-linear gauges. We will show that even though the sum of ghost term
and the gauge fixing term can always be expressed as a total BRST or a total
anti-BRST variation, we can express it as a combination of both of them only in
certain special gauges. We will also analyse the violation of nilpotency of the
BRST and the anti-BRST transformations by introduction of a bare mass term, in
the massive Curci-Ferrari gauge.
| [
{
"created": "Wed, 6 Oct 2010 12:59:20 GMT",
"version": "v1"
},
{
"created": "Thu, 21 Oct 2010 17:57:53 GMT",
"version": "v2"
}
] | 2011-01-25 | [
[
"Faizal",
"Mir",
""
]
] | In perturbative quantum gravity, the sum of the classical Lagrangian density, a gauge fixing term and a ghost term is invariant under two sets of supersymmetric transformations called the BRST and the anti-BRST transformations. In this paper we will analyse the BRST and the anti-BRST symmetries of perturbative quantum gravity in curved spacetime, in linear as well as non-linear gauges. We will show that even though the sum of ghost term and the gauge fixing term can always be expressed as a total BRST or a total anti-BRST variation, we can express it as a combination of both of them only in certain special gauges. We will also analyse the violation of nilpotency of the BRST and the anti-BRST transformations by introduction of a bare mass term, in the massive Curci-Ferrari gauge. |
2303.17364 | Charlie Hoy | Connor McIsaac, Charlie Hoy and Ian Harry | A search technique to observe precessing compact binary mergers in the
advanced detector era | 23 pages, 12 figures. For data release, see
https://icg-gravwaves.github.io/precessing_search_paper/ | null | null | LIGO-P2300071 | gr-qc astro-ph.HE astro-ph.IM | http://creativecommons.org/licenses/by/4.0/ | Gravitational-wave signals from compact binary coalescences are most
efficiently identified through matched filter searches, which match the data
against a pre-generated bank of gravitational-wave templates. Although
different techniques for performing the matched filter, as well as generating
the template bank, exist, currently all modelled gravitational-wave searches
use templates that restrict the component spins to be aligned (or anti-aligned)
with the orbital angular momentum. This means that current searches are less
sensitive to gravitational-wave signals generated from binaries with generic
spins (precessing), suggesting that, potentially, a significant fraction of
signals may remain undetected. In this work we introduce a matched filter
search that is sensitive to signals generated from precessing binaries and can
realistically be used during a gravitational-wave observing run. We take
advantage of the fact that a gravitational-wave signal from a precessing binary
can be decomposed into a power series of five harmonics, to show that a
generic-spin template bank, which is only $\sim 3\times$ larger than existing
aligned-spin banks, is needed to increase our sensitive volume by $\sim 100\%$
for neutron star black hole binaries with total mass larger than $17.5\,
M_{\odot}$ and in-plane spins $>0.67$. In fact, our generic spin search
performs as well as existing aligned-spin searches for neutron star black hole
signals with insignificant in-plane spins, but improves sensitivity by
$\sim60\%$ on average across the full generic spin parameter space. We
anticipate that this improved technique will identify significantly more
gravitational-wave signals, and, ultimately, help shed light on the unknown
spin distribution of binaries in the universe.
| [
{
"created": "Thu, 30 Mar 2023 13:27:43 GMT",
"version": "v1"
}
] | 2023-03-31 | [
[
"McIsaac",
"Connor",
""
],
[
"Hoy",
"Charlie",
""
],
[
"Harry",
"Ian",
""
]
] | Gravitational-wave signals from compact binary coalescences are most efficiently identified through matched filter searches, which match the data against a pre-generated bank of gravitational-wave templates. Although different techniques for performing the matched filter, as well as generating the template bank, exist, currently all modelled gravitational-wave searches use templates that restrict the component spins to be aligned (or anti-aligned) with the orbital angular momentum. This means that current searches are less sensitive to gravitational-wave signals generated from binaries with generic spins (precessing), suggesting that, potentially, a significant fraction of signals may remain undetected. In this work we introduce a matched filter search that is sensitive to signals generated from precessing binaries and can realistically be used during a gravitational-wave observing run. We take advantage of the fact that a gravitational-wave signal from a precessing binary can be decomposed into a power series of five harmonics, to show that a generic-spin template bank, which is only $\sim 3\times$ larger than existing aligned-spin banks, is needed to increase our sensitive volume by $\sim 100\%$ for neutron star black hole binaries with total mass larger than $17.5\, M_{\odot}$ and in-plane spins $>0.67$. In fact, our generic spin search performs as well as existing aligned-spin searches for neutron star black hole signals with insignificant in-plane spins, but improves sensitivity by $\sim60\%$ on average across the full generic spin parameter space. We anticipate that this improved technique will identify significantly more gravitational-wave signals, and, ultimately, help shed light on the unknown spin distribution of binaries in the universe. |
1801.02026 | Izzet Sakalli | G. Tokgoz and I. Sakalli | Spectroscopy of $z=0$ Lifshitz Black Hole | 9 pages, 1 figure | Advances in High Energy Physics Volume 2018, Article ID 3270790, 7
pages | 10.1155/2018/3270790 | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We studied the thermodynamics and spectroscopy of a $4$-dimensional, $z=0$
Lifshitz black hole ($Z0$LBH). Using the Wald's entropy formula and the Hawking
temperature, we derived the quasilocal mass of the $Z0$LBH. Based on the exact
solution to the near-horizon Zerilli equation of the massive scalar waves, we
computed the quasinormal modes of the $Z0$LBH via employing the adiabatic
invariant quantity for the $Z0$LBH. This study shows that the entropy and area
spectra of the $Z0$LBH are equally spaced.
| [
{
"created": "Sat, 6 Jan 2018 14:59:11 GMT",
"version": "v1"
}
] | 2018-12-05 | [
[
"Tokgoz",
"G.",
""
],
[
"Sakalli",
"I.",
""
]
] | We studied the thermodynamics and spectroscopy of a $4$-dimensional, $z=0$ Lifshitz black hole ($Z0$LBH). Using the Wald's entropy formula and the Hawking temperature, we derived the quasilocal mass of the $Z0$LBH. Based on the exact solution to the near-horizon Zerilli equation of the massive scalar waves, we computed the quasinormal modes of the $Z0$LBH via employing the adiabatic invariant quantity for the $Z0$LBH. This study shows that the entropy and area spectra of the $Z0$LBH are equally spaced. |
1003.5366 | Boris Hikin L | Boris Hikin | Einstein-Aether Theory With and Without Einstein | null | null | null | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The exact static spherically symmetric solutions for pure-aether theory and
Einstein-aether theory are presented. It is shown that both theories can
deliver the Schwarzschild metric, but only the Einstein-aether theory contains
solutions with "almost-Schwarzschild" metrics that satisfy Einstein's
experiments. Two specific solutions are of special interest: one in pure-aether
theory that derives the attractive nature of gravitation as a result of
Minskowski signature of the metric, and one - the Jacobson solution- of
Einstein-aether theory with "almost-Schwarzschild" metric and non-zero Ricci
tensor.
| [
{
"created": "Sun, 28 Mar 2010 12:43:30 GMT",
"version": "v1"
}
] | 2010-03-30 | [
[
"Hikin",
"Boris",
""
]
] | The exact static spherically symmetric solutions for pure-aether theory and Einstein-aether theory are presented. It is shown that both theories can deliver the Schwarzschild metric, but only the Einstein-aether theory contains solutions with "almost-Schwarzschild" metrics that satisfy Einstein's experiments. Two specific solutions are of special interest: one in pure-aether theory that derives the attractive nature of gravitation as a result of Minskowski signature of the metric, and one - the Jacobson solution- of Einstein-aether theory with "almost-Schwarzschild" metric and non-zero Ricci tensor. |
1005.0790 | Alessandro Gruppuso | Roberto Casadio and Alessandro Gruppuso | CMB acoustic scale in the entropic-like accelerating universe | 6 pages, 2 figures. Accepted for publication in Physical Review D | Phys.Rev.D84:023503,2011 | 10.1103/PhysRevD.84.023503 | null | gr-qc astro-ph.CO hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider generalizations of the entropic accelerating universe recently
proposed in Ref. [4,5] and show that their background equations can be made
equivalent to a model with a dark energy component with constant parameter of
state $w_{X} = -1 + 2\, \gamma /3$, where $\gamma$ is related to the
coefficients of the new terms in the Friedman equations. After discussing all
the Friedman equations for an arbitrary $\gamma$, we show how to recover the
standard scalings for dust and radiation. The acoustic scale $\ell_A$, related
to the peak positions in the pattern of the angular power spectrum of the
Cosmic Microwave Background anisotropies, is also computed and yields the
stringent bound $|\gamma|\ll 1$. We then argue that future data might be able
to distinguish this model from pure $\Lambda$CDM (corresponding to $\gamma=0$).
| [
{
"created": "Wed, 5 May 2010 16:47:13 GMT",
"version": "v1"
},
{
"created": "Sat, 18 Jun 2011 10:06:11 GMT",
"version": "v2"
}
] | 2011-08-08 | [
[
"Casadio",
"Roberto",
""
],
[
"Gruppuso",
"Alessandro",
""
]
] | We consider generalizations of the entropic accelerating universe recently proposed in Ref. [4,5] and show that their background equations can be made equivalent to a model with a dark energy component with constant parameter of state $w_{X} = -1 + 2\, \gamma /3$, where $\gamma$ is related to the coefficients of the new terms in the Friedman equations. After discussing all the Friedman equations for an arbitrary $\gamma$, we show how to recover the standard scalings for dust and radiation. The acoustic scale $\ell_A$, related to the peak positions in the pattern of the angular power spectrum of the Cosmic Microwave Background anisotropies, is also computed and yields the stringent bound $|\gamma|\ll 1$. We then argue that future data might be able to distinguish this model from pure $\Lambda$CDM (corresponding to $\gamma=0$). |
gr-qc/0602052 | Marc Lachieze-Rey | Marc Lachieze-Rey (APC) | The covariance of GPS coordinates and frames | new version, as to appear in CQG; some equations corrected, redaction
improved ; references added | Classical and Quantum Gravity, 23 (2006) 3531-3544 | 10.1088/0264-9381/23/10/019 | null | gr-qc astro-ph | null | We explore, in the general relativistic context, the properties of the
recently introduced GPS coordinates, as well as those of the associated frames
and coframes. We show that they are covariant, and completely independent of
any observer. We show that standard spectroscopic and astrometric observations
allow any observer to measure (i) the values of the GPS coordinates at his
position, (ii) the components of his [four-]velocity and (iii) the components
of the metric in the GPS frame. This provides to this system an unique value
both for conceptual discussion (no frame dependence) and for practical use
(involved quantities are directly measurable): localisation, motion monitoring,
astrometry, cosmography, tests of gravitation theories. We show explicitly, in
the general relativistic context, how an observer may estimate its position and
motion, and reconstruct the components of the metric. This arises from two main
results: the extension of the velocity fields of the probes to the whole
(curved) spacetime; and the identification of the components of the observer's
velocity in the GPS frame with the (inversed) observed redshifts of the probes.
Specific cases (non relativistic velocities; Minkowski and
Friedmann-Lema\^{i}tre spacetimes; geodesic motions) are studied in details.
| [
{
"created": "Tue, 14 Feb 2006 10:11:22 GMT",
"version": "v1"
},
{
"created": "Wed, 29 Mar 2006 11:46:20 GMT",
"version": "v2"
}
] | 2009-11-11 | [
[
"Lachieze-Rey",
"Marc",
"",
"APC"
]
] | We explore, in the general relativistic context, the properties of the recently introduced GPS coordinates, as well as those of the associated frames and coframes. We show that they are covariant, and completely independent of any observer. We show that standard spectroscopic and astrometric observations allow any observer to measure (i) the values of the GPS coordinates at his position, (ii) the components of his [four-]velocity and (iii) the components of the metric in the GPS frame. This provides to this system an unique value both for conceptual discussion (no frame dependence) and for practical use (involved quantities are directly measurable): localisation, motion monitoring, astrometry, cosmography, tests of gravitation theories. We show explicitly, in the general relativistic context, how an observer may estimate its position and motion, and reconstruct the components of the metric. This arises from two main results: the extension of the velocity fields of the probes to the whole (curved) spacetime; and the identification of the components of the observer's velocity in the GPS frame with the (inversed) observed redshifts of the probes. Specific cases (non relativistic velocities; Minkowski and Friedmann-Lema\^{i}tre spacetimes; geodesic motions) are studied in details. |
1411.0104 | Pedro Pina Avelino | P. P. Avelino | Could the dynamics of the Universe be influenced by what is going on
inside black holes? | 8 pages, 2 figures. Version 2 (accepted for publication in JCAP):
minor typos corrected | JCAP 1504 (2015) 024 | 10.1088/1475-7516/2015/04/024 | null | gr-qc astro-ph.CO hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We investigate the potential impact of mass inflation inside black holes on
the dynamics of the Universe, considering a recent reformulation of general
relativity, proposed in [1], which prevents the vacuum energy from acting as a
gravitational source. The interior dynamics of accreting black holes is
studied, at the classical level, using the homogeneous approximation and taking
charge as a surrogate for angular momentum. We show that, depending on the
accreting fluid properties, mass inflation inside black holes could influence
the value of the cosmological constant and thus the dynamics of the Universe. A
full assessment of the cosmological role played by black holes will require a
deeper understanding of the extremely energetic regimes expected inside real
astrophysical black holes, including their relation with the physics of the
very early Universe, and may eventually lead to an entirely new paradigm for
the origin and evolution of the Universe.
| [
{
"created": "Sat, 1 Nov 2014 11:29:46 GMT",
"version": "v1"
},
{
"created": "Thu, 26 Mar 2015 12:02:25 GMT",
"version": "v2"
}
] | 2015-05-06 | [
[
"Avelino",
"P. P.",
""
]
] | We investigate the potential impact of mass inflation inside black holes on the dynamics of the Universe, considering a recent reformulation of general relativity, proposed in [1], which prevents the vacuum energy from acting as a gravitational source. The interior dynamics of accreting black holes is studied, at the classical level, using the homogeneous approximation and taking charge as a surrogate for angular momentum. We show that, depending on the accreting fluid properties, mass inflation inside black holes could influence the value of the cosmological constant and thus the dynamics of the Universe. A full assessment of the cosmological role played by black holes will require a deeper understanding of the extremely energetic regimes expected inside real astrophysical black holes, including their relation with the physics of the very early Universe, and may eventually lead to an entirely new paradigm for the origin and evolution of the Universe. |
1707.05862 | Jonathan Sorce | Jonathan Sorce and Robert M. Wald | Gedanken Experiments to Destroy a Black Hole II: Kerr-Newman Black Holes
Cannot be Over-Charged or Over-Spun | 38 pages, 6 figures; minor revisions/corrections; version accepted
for publication in PRD | Phys. Rev. D 96, 104014 (2017) | 10.1103/PhysRevD.96.104014 | null | gr-qc hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider gedanken experiments to destroy an extremal or nearly extremal
Kerr-Newman black hole by causing it to absorb matter with sufficient charge
and/or angular momentum as compared with energy that it cannot remain a black
hole. It was previously shown by one of us that such gedanken experiments
cannot succeed for test particle matter entering an extremal Kerr-Newman black
hole. We generalize this result here to arbitrary matter entering an extremal
Kerr-Newman black hole, provided only that the non-electromagnetic contribution
to the stress-energy tensor of the matter satisfies the null energy condition.
We then analyze the gedanken experiments proposed by Hubeny and others to
over-charge and/or over-spin an initially slightly non-extremal Kerr-Newman
black hole. Analysis of such gedanken experiments requires that we calculate
all effects on the final mass of the black hole that are second-order in the
charge and angular momentum carried into the black hole, including all
self-force effects. We obtain a general formula for the full second order
correction to mass, $\delta^2 M$, which allows us to prove that no gedanken
experiments of the generalized Hubeny type can ever succeed in over-charging
and/or over-spinning a Kerr-Newman black hole, provided only that the
non-electromagnetic stress-energy tensor satisfies the null energy condition.
Our analysis is based upon Lagrangian methods, and our formula for the
second-order correction to mass is obtained by generalizing the canonical
energy analysis of Hollands and Wald to the Einstein-Maxwell case. Remarkably,
we obtain our formula for $\delta^2 M$ without having to explicitly compute
self-force or finite size effects. Indeed, in an appendix, we show explicitly
that our formula incorporates both the self-force and finite size effects for
the special case of a charged body slowly lowered into an uncharged black hole.
| [
{
"created": "Tue, 18 Jul 2017 21:23:44 GMT",
"version": "v1"
},
{
"created": "Fri, 13 Oct 2017 01:27:59 GMT",
"version": "v2"
},
{
"created": "Wed, 8 Nov 2017 18:43:09 GMT",
"version": "v3"
}
] | 2017-11-15 | [
[
"Sorce",
"Jonathan",
""
],
[
"Wald",
"Robert M.",
""
]
] | We consider gedanken experiments to destroy an extremal or nearly extremal Kerr-Newman black hole by causing it to absorb matter with sufficient charge and/or angular momentum as compared with energy that it cannot remain a black hole. It was previously shown by one of us that such gedanken experiments cannot succeed for test particle matter entering an extremal Kerr-Newman black hole. We generalize this result here to arbitrary matter entering an extremal Kerr-Newman black hole, provided only that the non-electromagnetic contribution to the stress-energy tensor of the matter satisfies the null energy condition. We then analyze the gedanken experiments proposed by Hubeny and others to over-charge and/or over-spin an initially slightly non-extremal Kerr-Newman black hole. Analysis of such gedanken experiments requires that we calculate all effects on the final mass of the black hole that are second-order in the charge and angular momentum carried into the black hole, including all self-force effects. We obtain a general formula for the full second order correction to mass, $\delta^2 M$, which allows us to prove that no gedanken experiments of the generalized Hubeny type can ever succeed in over-charging and/or over-spinning a Kerr-Newman black hole, provided only that the non-electromagnetic stress-energy tensor satisfies the null energy condition. Our analysis is based upon Lagrangian methods, and our formula for the second-order correction to mass is obtained by generalizing the canonical energy analysis of Hollands and Wald to the Einstein-Maxwell case. Remarkably, we obtain our formula for $\delta^2 M$ without having to explicitly compute self-force or finite size effects. Indeed, in an appendix, we show explicitly that our formula incorporates both the self-force and finite size effects for the special case of a charged body slowly lowered into an uncharged black hole. |
0908.1322 | Nadiezhda Montelongo | N. Montelongo Garcia, T. Zannias | On the Structure of the Effective Potential for a Spherical Wormhole | 15 pages, 0 figures | Phys. Rev. D 78, 064003 (2008) | 10.1103/PhysRevD.78.064003 | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The structure of the effective potential $V$ describing causal geodesics near
the throat of an arbitrary spherical wormhole is analyzed. Einstein's equations
relative to a set of regular coordinates covering a vicinity of the throat
imply that any spherical wormhole can be constructed from solutions of an
effective initial value problem with the throat serving as an initial value
surface. The initial data involve matter variables, the area A(0) of the throat
and the gradient $\Lambda(0)$ of the red shift factor on the throat. Whenever
$\Lambda(0)=0$, the effective potential $V$ has a critical point on the throat.
Conditions upon the data are derived ensuring that the critical point is a
local minimum (resp. maximum). For particular families of Quasi-Schwarzschild
wormholes, $V$ exhibits a local minimum on the throat independently upon the
energy $E$ and angular momentum $L^2 $ of the test particles and thus such
wormholes admit stable circular timelike and null geodesics on the throat. For
families of Chaplygin wormholes, we show that such geodesics are unstable.
Based on a suitable power series representation of the metric, properties of
$V$ away from the throat are obtained that are useful for the analysis of
accretion disks and radiation processes near the throat of any spherical
wormhole.
| [
{
"created": "Mon, 10 Aug 2009 13:33:43 GMT",
"version": "v1"
}
] | 2015-05-13 | [
[
"Garcia",
"N. Montelongo",
""
],
[
"Zannias",
"T.",
""
]
] | The structure of the effective potential $V$ describing causal geodesics near the throat of an arbitrary spherical wormhole is analyzed. Einstein's equations relative to a set of regular coordinates covering a vicinity of the throat imply that any spherical wormhole can be constructed from solutions of an effective initial value problem with the throat serving as an initial value surface. The initial data involve matter variables, the area A(0) of the throat and the gradient $\Lambda(0)$ of the red shift factor on the throat. Whenever $\Lambda(0)=0$, the effective potential $V$ has a critical point on the throat. Conditions upon the data are derived ensuring that the critical point is a local minimum (resp. maximum). For particular families of Quasi-Schwarzschild wormholes, $V$ exhibits a local minimum on the throat independently upon the energy $E$ and angular momentum $L^2 $ of the test particles and thus such wormholes admit stable circular timelike and null geodesics on the throat. For families of Chaplygin wormholes, we show that such geodesics are unstable. Based on a suitable power series representation of the metric, properties of $V$ away from the throat are obtained that are useful for the analysis of accretion disks and radiation processes near the throat of any spherical wormhole. |
gr-qc/0207123 | Orfeu Bertolami | O. Bertolami and M. Tajmar | Hypothetical Gravity Control and Implications for Spacecraft Propulsion | 5 pages, plain Latex | null | null | DF/IST-8.02 | gr-qc | null | A scientific analysis of the conditions under which gravity could be
controlled and the implications that an hypothetical manipulation of gravity
would have for known schemes of space propulsion have been the scope of a
recent study carried out for the European Space Agency. The underlying
fundamental physical principles of known theories of gravity were analysed and
shown that even if gravity could be modified it would bring somewhat modest
gains in terms of launching of spacecraft and no breakthrough for space
propulsion.
| [
{
"created": "Wed, 31 Jul 2002 12:40:45 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Bertolami",
"O.",
""
],
[
"Tajmar",
"M.",
""
]
] | A scientific analysis of the conditions under which gravity could be controlled and the implications that an hypothetical manipulation of gravity would have for known schemes of space propulsion have been the scope of a recent study carried out for the European Space Agency. The underlying fundamental physical principles of known theories of gravity were analysed and shown that even if gravity could be modified it would bring somewhat modest gains in terms of launching of spacecraft and no breakthrough for space propulsion. |
gr-qc/0212129 | S. K. Sahay | S.K. Sahay | Matching of the continuous gravitational wave in an all sky search | 16 pages, 7 figures, 3 Tables, To appear in Int. J. Mod. Phys. D | Int.J.Mod.Phys.D12:1227-1240,2003 | 10.1142/S0218271803003578 | null | gr-qc astro-ph | null | We investigate the matching of continuous gravitational wave (CGW) signals in
an all sky search with reference to Earth based laser interferometric
detectors. We consider the source location as the parameters of the signal
manifold and templates corresponding to different source locations. It has been
found that the matching of signals from locations in the sky that differ in
their co-latitude and longitude by $\pi$ radians decreases with source
frequency. We have also made an analysis with the other parameters affecting
the symmetries. We observe that it may not be relevant to take care of the
symmetries in the sky locations for the search of CGW from the output of
LIGO-I, GEO600 and TAMA detectors.
| [
{
"created": "Tue, 31 Dec 2002 14:53:28 GMT",
"version": "v1"
},
{
"created": "Mon, 24 Mar 2003 15:55:03 GMT",
"version": "v2"
}
] | 2014-11-17 | [
[
"Sahay",
"S. K.",
""
]
] | We investigate the matching of continuous gravitational wave (CGW) signals in an all sky search with reference to Earth based laser interferometric detectors. We consider the source location as the parameters of the signal manifold and templates corresponding to different source locations. It has been found that the matching of signals from locations in the sky that differ in their co-latitude and longitude by $\pi$ radians decreases with source frequency. We have also made an analysis with the other parameters affecting the symmetries. We observe that it may not be relevant to take care of the symmetries in the sky locations for the search of CGW from the output of LIGO-I, GEO600 and TAMA detectors. |
gr-qc/0612139 | Christophe Real | Christophe Real | Conservation of energy and Gauss Bonnet gravity | 10 pages | null | null | null | gr-qc | null | It is shown how can be made the classification of all tensors constructed
from the Riemann tensor that verify the conservation of gravitational energy
momentum. More precisely we explain that there exists a unique tensor of degree
n in the Riemann tensor and its contractions that verifies the conservation of
energy. We show that this tensor, only because it obeys this degree n structure
as well as energy conservation, two facts which are true in all dimensions,
verifies in dimension 2n this striking particularity of being Euler gravity. We
stick here to the case n=2 but explain briefly why the general case is similar.
| [
{
"created": "Thu, 21 Dec 2006 18:47:25 GMT",
"version": "v1"
},
{
"created": "Wed, 7 Nov 2007 16:59:58 GMT",
"version": "v2"
}
] | 2007-11-07 | [
[
"Real",
"Christophe",
""
]
] | It is shown how can be made the classification of all tensors constructed from the Riemann tensor that verify the conservation of gravitational energy momentum. More precisely we explain that there exists a unique tensor of degree n in the Riemann tensor and its contractions that verifies the conservation of energy. We show that this tensor, only because it obeys this degree n structure as well as energy conservation, two facts which are true in all dimensions, verifies in dimension 2n this striking particularity of being Euler gravity. We stick here to the case n=2 but explain briefly why the general case is similar. |
0811.2832 | Ali Shojai | Fatimah Shojai, and Ali Shojai | Geodesic Congruences in the Palatini f(R) Theory | null | Phys.Rev.D78:104011,2008 | 10.1103/PhysRevD.78.104011 | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We shall investigate the properties of a congruence of geodesics in the
framework of Palatini f(R) theories. We shall evaluate the modified geodesic
deviation equation and the Raychaudhuri's equation and show that f(R) Palatini
theories do not necessarily lead to attractive forces. Also we shall study
energy condition for f(R) Palatini gravity via a perturbative analysis of the
Raychaudhuri's equation.
| [
{
"created": "Tue, 18 Nov 2008 03:47:22 GMT",
"version": "v1"
}
] | 2008-12-18 | [
[
"Shojai",
"Fatimah",
""
],
[
"Shojai",
"Ali",
""
]
] | We shall investigate the properties of a congruence of geodesics in the framework of Palatini f(R) theories. We shall evaluate the modified geodesic deviation equation and the Raychaudhuri's equation and show that f(R) Palatini theories do not necessarily lead to attractive forces. Also we shall study energy condition for f(R) Palatini gravity via a perturbative analysis of the Raychaudhuri's equation. |
1003.2481 | Stephen Privitera | The LIGO Scientific Collaboration, the Virgo Collaboration: J. Abadie,
B. P. Abbott, R. Abbott, M Abernathy, T. Accadia, F. Acernese, C. Adams, R.
Adhikari, P. Ajith, B. Allen, G. Allen, E. Amador Ceron, R. S. Amin, S. B.
Anderson, W. G. Anderson, F. Antonucci, S. Aoudia, M. A. Arain, M. Araya, M.
Aronsson, K. G. Arun, Y. Aso, S. Aston, P. Astone, D. E. Atkinson, P.
Aufmuth, C. Aulbert, S. Babak, P. Baker, G. Ballardin, S. Ballmer, D. Barker,
S. Barnum, F. Barone, B. Barr, P. Barriga, L. Barsotti, M. Barsuglia, M. A.
Barton, I. Bartos, R. Bassiri, M. Bastarrika, J. Bauchrowitz, Th. S. Bauer,
B. Behnke, M.G. Beker, M. Benacquista, A. Bertolini, J. Betzwieser, N.
Beveridge, P. T. Beyersdorf, S. Bigotta, I. A. Bilenko, G. Billingsley, J.
Birch, S. Birindelli, R. Biswas, M. Bitossi, M. A. Bizouard, E. Black, J. K.
Blackburn, L. Blackburn, D. Blair, B. Bland, M. Blom, C. Boccara, O. Bock, T.
P. Bodiya, R. Bondarescu, F. Bondu, L. Bonelli, R. Bork, M. Born, S. Bose, L.
Bosi, M. Boyle, S. Braccini, C. Bradaschia, P. R. Brady, V. B. Braginsky, J.
E. Brau, J. Breyer, D. O. Bridges, A. Brillet, M. Brinkmann, V. Brisson, M.
Britzger, A. F. Brooks, D. A. Brown, R. Budzy\'nski, T. Bulik, H. J. Bulten,
A. Buonanno, J. Burguet--Castell, O. Burmeister, D. Buskulic, R. L. Byer, L.
Cadonati, G. Cagnoli, E. Calloni, J. B. Camp, E. Campagna, P. Campsie, J.
Cannizzo, K. C. Cannon, B. Canuel, J. Cao, C. Capano, F. Carbognani, S.
Caride, S. Caudill, M. Cavagli\`a, F. Cavalier, R. Cavalieri, G. Cella, C.
Cepeda, E. Cesarini, T. Chalermsongsak, E. Chalkley, P. Charlton, E.
Chassande-Mottin, S. Chelkowski, Y. Chen, A. Chincarini, N. Christensen, S.
S. Y. Chua, C. T. Y. Chung, D. Clark, J. Clark, J. H. Clayton, F. Cleva, E.
Coccia, C. N. Colacino, J. Colas, A. Colla, M. Colombini, R. Conte, D. Cook,
T. R. Corbitt, C. Corda, N. Cornish, A. Corsi, C. A. Costa, J.-P. Coulon, D.
Coward, D. C. Coyne, J. D. E. Creighton, T. D. Creighton, A. M. Cruise, R. M.
Culter, A. Cumming, L. Cunningham, E. Cuoco, K. Dahl, S. L. Danilishin, R.
Dannenberg, S. D'Antonio, K. Danzmann, A. Dari, K. Das, V. Dattilo, B.
Daudert, M. Davier, G. Davies, A. Davis, E. J. Daw, R. Day, T. Dayanga, R. De
Rosa, D. DeBra, J. Degallaix, M. del Prete, V. Dergachev, R. DeRosa, R.
DeSalvo, P. Devanka, S. Dhurandhar, L. Di Fiore, A. Di Lieto, I. Di Palma, M.
Di Paolo Emilio, A. Di Virgilio, M. D\'iaz, A. Dietz, F. Donovan, K. L.
Dooley, E. E. Doomes, S. Dorsher, E. S. D. Douglas, M. Drago, R. W. P.
Drever, J. C. Driggers, J. Dueck, J.-C. Dumas, T. Eberle, M. Edgar, M.
Edwards, A. Effler, P. Ehrens, R. Engel, T. Etzel, M. Evans, T. Evans, V.
Fafone, S. Fairhurst, Y. Fan, B. F. Farr, D. Fazi, H. Fehrmann, D. Feldbaum,
I. Ferrante, F. Fidecaro, L. S. Finn, I. Fiori, R. Flaminio, M. Flanigan, K.
Flasch, S. Foley, C. Forrest, E. Forsi, N. Fotopoulos, J.-D. Fournier, J.
Franc, S. Frasca, F. Frasconi, M. Frede, M. Frei, Z. Frei, A. Freise, R.
Frey, T. T. Fricke, D. Friedrich, P. Fritschel, V. V. Frolov, P. Fulda, M.
Fyffe, L. Gammaitoni, J. A. Garofoli, F. Garufi, G. Gemme, E. Genin, A.
Gennai, I. Gholami, S. Ghosh, J. A. Giaime, S. Giampanis, K. D. Giardina, A.
Giazotto, C. Gill, E. Goetz, L. M. Goggin, G. Gonz\'alez, M. L. Gorodetsky,
S. Go{\ss}ler, R. Gouaty, C. Graef, M. Granata, A. Grant, S. Gras, C. Gray,
R. J. S. Greenhalgh, A. M. Gretarsson, C. Greverie, R. Grosso, H. Grote, S.
Grunewald, G. M. Guidi, E. K. Gustafson, R. Gustafson, B. Hage, P. Hall, J.
M. Hallam, D. Hammer, G. Hammond, J. Hanks, C. Hanna, J. Hanson, J. Harms, G.
M. Harry, I. W. Harry, E. D. Harstad, K. Haughian, K. Hayama, J. Heefner, H.
Heitmann, P. Hello, I. S. Heng, A. Heptonstall, M. Hewitson, S. Hild, E.
Hirose, D. Hoak, K. A. Hodge, K. Holt, D. J. Hosken, J. Hough, E. Howell, D.
Hoyland, D. Huet, B. Hughey, S. Husa, S. H. Huttner, T. Huynh--Dinh, D. R.
Ingram, R. Inta, T. Isogai, A. Ivanov, P. Jaranowski, W. W. Johnson, D. I.
Jones, G. Jones, R. Jones, L. Ju, P. Kalmus, V. Kalogera, S. Kandhasamy, J.
Kanner, E. Katsavounidis, K. Kawabe, S. Kawamura, F. Kawazoe, W. Kells, D. G.
Keppel, A. Khalaidovski, F. Y. Khalili, E. A. Khazanov, C. Kim, H. Kim, P. J.
King, D. L. Kinzel, J. S. Kissel, S. Klimenko, V. Kondrashov, R. Kopparapu,
S. Koranda, I. Kowalska, D. Kozak, T. Krause, V. Kringel, S. Krishnamurthy,
B. Krishnan, A. Kr\'olak, G. Kuehn, J. Kullman, R. Kumar, P. Kwee, M. Landry,
M. Lang, B. Lantz, N. Lastzka, A. Lazzarini, P. Leaci, J. Leong, I. Leonor,
N. Leroy, N. Letendre, J. Li, T. G. F. Li, H. Lin, P. E. Lindquist, N. A.
Lockerbie, D. Lodhia, M. Lorenzini, V. Loriette, M. Lormand, G. Losurdo, P.
Lu, J. Luan, M. Lubinski, A. Lucianetti, H. L\"uck, A. Lundgren, B.
Machenschalk, M. MacInnis, J. M. Mackowski, M. Mageswaran, K. Mailand, E.
Majorana, C. Mak, N. Man, I. Mandel, V. Mandic, M. Mantovani, F. Marchesoni,
F. Marion, S. M\'arka, Z. M\'arka, E. Maros, J. Marque, F. Martelli, I. W.
Martin, R. M. Martin, J. N. Marx, K. Mason, A. Masserot, F. Matichard, L.
Matone, R. A. Matzner, N. Mavalvala, R. McCarthy, D. E. McClelland, S. C.
McGuire, G. McIntyre, G. McIvor, D. J. A. McKechan, G. Meadors, M. Mehmet, T.
Meier, A. Melatos, A. C. Melissinos, G. Mendell, D. F. Men\'endez, R. A.
Mercer, L. Merill, S. Meshkov, C. Messenger, M. S. Meyer, H. Miao, C. Michel,
L. Milano, J. Miller, Y. Minenkov, Y. Mino, S. Mitra, V. P. Mitrofanov, G.
Mitselmakher, R. Mittleman, B. Moe, M. Mohan, S. D. Mohanty, S. R. P.
Mohapatra, D. Moraru, J. Moreau, G. Moreno, N. Morgado, A. Morgia, T.
Morioka, K. Mors, S. Mosca, V. Moscatelli, K. Mossavi, B. Mours, C. MowLowry,
G. Mueller, S. Mukherjee, A. Mullavey, H. M\"uller-Ebhardt, J. Munch, P. G.
Murray, T. Nash, R. Nawrodt, J. Nelson, I. Neri, G. Newton, A. Nishizawa, F.
Nocera, D. Nolting, E. Ochsner, J. O'Dell, G. H. Ogin, R. G. Oldenburg, B.
O'Reilly, R. O'Shaughnessy, C. Osthelder, D. J. Ottaway, R. S. Ottens, H.
Overmier, B. J. Owen, A. Page, G. Pagliaroli, L. Palladino, C. Palomba, Y.
Pan, C. Pankow, F. Paoletti, M. A. Papa, S. Pardi, M. Pareja, M. Parisi, A.
Pasqualetti, R. Passaquieti, D. Passuello, P. Patel, M. Pedraza, L. Pekowsky,
S. Penn, C. Peralta, A. Perreca, G. Persichetti, M. Pichot, M. Pickenpack, F.
Piergiovanni, M. Pietka, L. Pinard, I. M. Pinto, M. Pitkin, H. J. Pletsch, M.
V. Plissi, R. Poggiani, F. Postiglione, M. Prato, V. Predoi, L. R. Price, M.
Prijatelj, M. Principe, S. Privitera, R. Prix, G. A. Prodi, L. Prokhorov, O.
Puncken, M. Punturo, P. Puppo, V. Quetschke, F. J. Raab, O. Rabaste, D. S.
Rabeling, T. Radke, H. Radkins, P. Raffai, M. Rakhmanov, B. Rankins, P.
Rapagnani, V. Raymond, V. Re, C. M. Reed, T. Reed, T. Regimbau, S. Reid, D.
H. Reitze, F. Ricci, R. Riesen, K. Riles, P. Roberts, N. A. Robertson, F.
Robinet, C. Robinson, E. L. Robinson, A. Rocchi, S. Roddy, C. R\"over, L.
Rolland, J. Rollins, J. D. Romano, R. Romano, J. H. Romie, D. Rosi\'nska, S.
Rowan, A. R\"udiger, P. Ruggi, K. Ryan, S. Sakata, M. Sakosky, F. Salemi, L.
Sammut, L. Sancho de la Jordana, V. Sandberg, V. Sannibale, L. Santamar\'ia,
G. Santostasi, S. Saraf, B. Sassolas, B. S. Sathyaprakash, S. Sato, M.
Satterthwaite, P. R. Saulson, R. Savage, R. Schilling, R. Schnabel, R.
Schofield, B. Schulz, B. F. Schutz, P. Schwinberg, J. Scott, S. M. Scott, A.
C. Searle, F. Seifert, D. Sellers, A. S. Sengupta, D. Sentenac, A. Sergeev,
D. Shaddock, B. Shapiro, P. Shawhan, D. H. Shoemaker, A. Sibley, X. Siemens,
D. Sigg, A. Singer, A. M. Sintes, G. Skelton, B. J. J. Slagmolen, J. Slutsky,
J. R. Smith, M. R. Smith, N. D. Smith, K. Somiya, B. Sorazu, F. C. Speirits,
A. J. Stein, L. C. Stein, S. Steinlechner, S. Steplewski, A. Stochino, R.
Stone, K. A. Strain, S. Strigin, A. Stroeer, R. Sturani, A. L. Stuver, T. Z.
Summerscales, M. Sung, S. Susmithan, P. J. Sutton, B. Swinkels, D. Talukder,
D. B. Tanner, S. P. Tarabrin, J. R. Taylor, R. Taylor, P. Thomas, K. A.
Thorne, K. S. Thorne, E. Thrane, A. Th\"uring, C. Titsler, K. V. Tokmakov, A.
Toncelli, M. Tonelli, C. Torres, C. I. Torrie, E. Tournefier, F. Travasso, G.
Traylor, M. Trias, J. Trummer, K. Tseng, D. Ugolini, K. Urbanek, H.
Vahlbruch, B. Vaishnav, G. Vajente, M. Vallisneri, J. F. J. van den Brand, C.
Van Den Broeck, S. van der Putten, M. V. van der Sluys, A. A. van Veggel, S.
Vass, R. Vaulin, M. Vavoulidis, A. Vecchio, G. Vedovato, J. Veitch, P. J.
Veitch, C. Veltkamp, D. Verkindt, F. Vetrano, A. Vicer\'e, A. Villar, J.-Y.
Vinet, H. Vocca, C. Vorvick, S. P. Vyachanin, S. J. Waldman, L. Wallace, A.
Wanner, R. L. Ward, M. Was, P. Wei, M. Weinert, A. J. Weinstein, R. Weiss, L.
Wen, S. Wen, P. Wessels, M. West, T. Westphal, K. Wette, J. T. Whelan, S. E.
Whitcomb, D. J. White, B. F. Whiting, C. Wilkinson, P. A. Willems, L.
Williams, B. Willke, L. Winkelmann, W. Winkler, C. C. Wipf, A. G. Wiseman, G.
Woan, R. Wooley, J. Worden, I. Yakushin, H. Yamamoto, K. Yamamoto, D.
Yeaton-Massey, S. Yoshida, P. P. Yu, M. Yvert, M. Zanolin, L. Zhang, Z.
Zhang, C. Zhao, N. Zotov, M. E. Zucker, J. Zweizig, K. Belczynski | Sensitivity to Gravitational Waves from Compact Binary Coalescences
Achieved during LIGO's Fifth and Virgo's First Science Run | 12 pages, 5 figures | null | null | LIGO-T0900499-v19, VIR-0171A-10 | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We summarize the sensitivity achieved by the LIGO and Virgo gravitational
wave detectors for compact binary coalescence (CBC) searches during LIGO's
fifth science run and Virgo's first science run. We present noise spectral
density curves for each of the four detectors that operated during these
science runs which are representative of the typical performance achieved by
the detectors for CBC searches. These spectra are intended for release to the
public as a summary of detector performance for CBC searches during these
science runs.
| [
{
"created": "Fri, 12 Mar 2010 05:48:36 GMT",
"version": "v1"
},
{
"created": "Sun, 28 Mar 2010 22:46:53 GMT",
"version": "v2"
},
{
"created": "Tue, 1 Jun 2010 04:45:05 GMT",
"version": "v3"
}
] | 2015-03-13 | [
[
"The LIGO Scientific Collaboration",
"",
""
],
[
"the Virgo Collaboration",
"",
""
],
[
"Abadie",
"J.",
""
],
[
"Abbott",
"B. P.",
""
],
[
"Abbott",
"R.",
""
],
[
"Abernathy",
"M",
""
],
[
"Accadia",
"T.",
""
],
[
"Acernese",
"F.",
""
],
[
"Adams",
"C.",
""
],
[
"Adhikari",
"R.",
""
],
[
"Ajith",
"P.",
""
],
[
"Allen",
"B.",
""
],
[
"Allen",
"G.",
""
],
[
"Ceron",
"E. Amador",
""
],
[
"Amin",
"R. S.",
""
],
[
"Anderson",
"S. B.",
""
],
[
"Anderson",
"W. G.",
""
],
[
"Antonucci",
"F.",
""
],
[
"Aoudia",
"S.",
""
],
[
"Arain",
"M. A.",
""
],
[
"Araya",
"M.",
""
],
[
"Aronsson",
"M.",
""
],
[
"Arun",
"K. G.",
""
],
[
"Aso",
"Y.",
""
],
[
"Aston",
"S.",
""
],
[
"Astone",
"P.",
""
],
[
"Atkinson",
"D. E.",
""
],
[
"Aufmuth",
"P.",
""
],
[
"Aulbert",
"C.",
""
],
[
"Babak",
"S.",
""
],
[
"Baker",
"P.",
""
],
[
"Ballardin",
"G.",
""
],
[
"Ballmer",
"S.",
""
],
[
"Barker",
"D.",
""
],
[
"Barnum",
"S.",
""
],
[
"Barone",
"F.",
""
],
[
"Barr",
"B.",
""
],
[
"Barriga",
"P.",
""
],
[
"Barsotti",
"L.",
""
],
[
"Barsuglia",
"M.",
""
],
[
"Barton",
"M. A.",
""
],
[
"Bartos",
"I.",
""
],
[
"Bassiri",
"R.",
""
],
[
"Bastarrika",
"M.",
""
],
[
"Bauchrowitz",
"J.",
""
],
[
"Bauer",
"Th. S.",
""
],
[
"Behnke",
"B.",
""
],
[
"Beker",
"M. G.",
""
],
[
"Benacquista",
"M.",
""
],
[
"Bertolini",
"A.",
""
],
[
"Betzwieser",
"J.",
""
],
[
"Beveridge",
"N.",
""
],
[
"Beyersdorf",
"P. T.",
""
],
[
"Bigotta",
"S.",
""
],
[
"Bilenko",
"I. A.",
""
],
[
"Billingsley",
"G.",
""
],
[
"Birch",
"J.",
""
],
[
"Birindelli",
"S.",
""
],
[
"Biswas",
"R.",
""
],
[
"Bitossi",
"M.",
""
],
[
"Bizouard",
"M. A.",
""
],
[
"Black",
"E.",
""
],
[
"Blackburn",
"J. K.",
""
],
[
"Blackburn",
"L.",
""
],
[
"Blair",
"D.",
""
],
[
"Bland",
"B.",
""
],
[
"Blom",
"M.",
""
],
[
"Boccara",
"C.",
""
],
[
"Bock",
"O.",
""
],
[
"Bodiya",
"T. P.",
""
],
[
"Bondarescu",
"R.",
""
],
[
"Bondu",
"F.",
""
],
[
"Bonelli",
"L.",
""
],
[
"Bork",
"R.",
""
],
[
"Born",
"M.",
""
],
[
"Bose",
"S.",
""
],
[
"Bosi",
"L.",
""
],
[
"Boyle",
"M.",
""
],
[
"Braccini",
"S.",
""
],
[
"Bradaschia",
"C.",
""
],
[
"Brady",
"P. R.",
""
],
[
"Braginsky",
"V. B.",
""
],
[
"Brau",
"J. E.",
""
],
[
"Breyer",
"J.",
""
],
[
"Bridges",
"D. O.",
""
],
[
"Brillet",
"A.",
""
],
[
"Brinkmann",
"M.",
""
],
[
"Brisson",
"V.",
""
],
[
"Britzger",
"M.",
""
],
[
"Brooks",
"A. F.",
""
],
[
"Brown",
"D. A.",
""
],
[
"Budzyński",
"R.",
""
],
[
"Bulik",
"T.",
""
],
[
"Bulten",
"H. J.",
""
],
[
"Buonanno",
"A.",
""
],
[
"Burguet--Castell",
"J.",
""
],
[
"Burmeister",
"O.",
""
],
[
"Buskulic",
"D.",
""
],
[
"Byer",
"R. L.",
""
],
[
"Cadonati",
"L.",
""
],
[
"Cagnoli",
"G.",
""
],
[
"Calloni",
"E.",
""
],
[
"Camp",
"J. B.",
""
],
[
"Campagna",
"E.",
""
],
[
"Campsie",
"P.",
""
],
[
"Cannizzo",
"J.",
""
],
[
"Cannon",
"K. C.",
""
],
[
"Canuel",
"B.",
""
],
[
"Cao",
"J.",
""
],
[
"Capano",
"C.",
""
],
[
"Carbognani",
"F.",
""
],
[
"Caride",
"S.",
""
],
[
"Caudill",
"S.",
""
],
[
"Cavaglià",
"M.",
""
],
[
"Cavalier",
"F.",
""
],
[
"Cavalieri",
"R.",
""
],
[
"Cella",
"G.",
""
],
[
"Cepeda",
"C.",
""
],
[
"Cesarini",
"E.",
""
],
[
"Chalermsongsak",
"T.",
""
],
[
"Chalkley",
"E.",
""
],
[
"Charlton",
"P.",
""
],
[
"Chassande-Mottin",
"E.",
""
],
[
"Chelkowski",
"S.",
""
],
[
"Chen",
"Y.",
""
],
[
"Chincarini",
"A.",
""
],
[
"Christensen",
"N.",
""
],
[
"Chua",
"S. S. Y.",
""
],
[
"Chung",
"C. T. Y.",
""
],
[
"Clark",
"D.",
""
],
[
"Clark",
"J.",
""
],
[
"Clayton",
"J. H.",
""
],
[
"Cleva",
"F.",
""
],
[
"Coccia",
"E.",
""
],
[
"Colacino",
"C. N.",
""
],
[
"Colas",
"J.",
""
],
[
"Colla",
"A.",
""
],
[
"Colombini",
"M.",
""
],
[
"Conte",
"R.",
""
],
[
"Cook",
"D.",
""
],
[
"Corbitt",
"T. R.",
""
],
[
"Corda",
"C.",
""
],
[
"Cornish",
"N.",
""
],
[
"Corsi",
"A.",
""
],
[
"Costa",
"C. A.",
""
],
[
"Coulon",
"J. -P.",
""
],
[
"Coward",
"D.",
""
],
[
"Coyne",
"D. C.",
""
],
[
"Creighton",
"J. D. E.",
""
],
[
"Creighton",
"T. D.",
""
],
[
"Cruise",
"A. M.",
""
],
[
"Culter",
"R. M.",
""
],
[
"Cumming",
"A.",
""
],
[
"Cunningham",
"L.",
""
],
[
"Cuoco",
"E.",
""
],
[
"Dahl",
"K.",
""
],
[
"Danilishin",
"S. L.",
""
],
[
"Dannenberg",
"R.",
""
],
[
"D'Antonio",
"S.",
""
],
[
"Danzmann",
"K.",
""
],
[
"Dari",
"A.",
""
],
[
"Das",
"K.",
""
],
[
"Dattilo",
"V.",
""
],
[
"Daudert",
"B.",
""
],
[
"Davier",
"M.",
""
],
[
"Davies",
"G.",
""
],
[
"Davis",
"A.",
""
],
[
"Daw",
"E. J.",
""
],
[
"Day",
"R.",
""
],
[
"Dayanga",
"T.",
""
],
[
"De Rosa",
"R.",
""
],
[
"DeBra",
"D.",
""
],
[
"Degallaix",
"J.",
""
],
[
"del Prete",
"M.",
""
],
[
"Dergachev",
"V.",
""
],
[
"DeRosa",
"R.",
""
],
[
"DeSalvo",
"R.",
""
],
[
"Devanka",
"P.",
""
],
[
"Dhurandhar",
"S.",
""
],
[
"Di Fiore",
"L.",
""
],
[
"Di Lieto",
"A.",
""
],
[
"Di Palma",
"I.",
""
],
[
"Emilio",
"M. Di Paolo",
""
],
[
"Di Virgilio",
"A.",
""
],
[
"Díaz",
"M.",
""
],
[
"Dietz",
"A.",
""
],
[
"Donovan",
"F.",
""
],
[
"Dooley",
"K. L.",
""
],
[
"Doomes",
"E. E.",
""
],
[
"Dorsher",
"S.",
""
],
[
"Douglas",
"E. S. D.",
""
],
[
"Drago",
"M.",
""
],
[
"Drever",
"R. W. P.",
""
],
[
"Driggers",
"J. C.",
""
],
[
"Dueck",
"J.",
""
],
[
"Dumas",
"J. -C.",
""
],
[
"Eberle",
"T.",
""
],
[
"Edgar",
"M.",
""
],
[
"Edwards",
"M.",
""
],
[
"Effler",
"A.",
""
],
[
"Ehrens",
"P.",
""
],
[
"Engel",
"R.",
""
],
[
"Etzel",
"T.",
""
],
[
"Evans",
"M.",
""
],
[
"Evans",
"T.",
""
],
[
"Fafone",
"V.",
""
],
[
"Fairhurst",
"S.",
""
],
[
"Fan",
"Y.",
""
],
[
"Farr",
"B. F.",
""
],
[
"Fazi",
"D.",
""
],
[
"Fehrmann",
"H.",
""
],
[
"Feldbaum",
"D.",
""
],
[
"Ferrante",
"I.",
""
],
[
"Fidecaro",
"F.",
""
],
[
"Finn",
"L. S.",
""
],
[
"Fiori",
"I.",
""
],
[
"Flaminio",
"R.",
""
],
[
"Flanigan",
"M.",
""
],
[
"Flasch",
"K.",
""
],
[
"Foley",
"S.",
""
],
[
"Forrest",
"C.",
""
],
[
"Forsi",
"E.",
""
],
[
"Fotopoulos",
"N.",
""
],
[
"Fournier",
"J. -D.",
""
],
[
"Franc",
"J.",
""
],
[
"Frasca",
"S.",
""
],
[
"Frasconi",
"F.",
""
],
[
"Frede",
"M.",
""
],
[
"Frei",
"M.",
""
],
[
"Frei",
"Z.",
""
],
[
"Freise",
"A.",
""
],
[
"Frey",
"R.",
""
],
[
"Fricke",
"T. T.",
""
],
[
"Friedrich",
"D.",
""
],
[
"Fritschel",
"P.",
""
],
[
"Frolov",
"V. V.",
""
],
[
"Fulda",
"P.",
""
],
[
"Fyffe",
"M.",
""
],
[
"Gammaitoni",
"L.",
""
],
[
"Garofoli",
"J. A.",
""
],
[
"Garufi",
"F.",
""
],
[
"Gemme",
"G.",
""
],
[
"Genin",
"E.",
""
],
[
"Gennai",
"A.",
""
],
[
"Gholami",
"I.",
""
],
[
"Ghosh",
"S.",
""
],
[
"Giaime",
"J. A.",
""
],
[
"Giampanis",
"S.",
""
],
[
"Giardina",
"K. D.",
""
],
[
"Giazotto",
"A.",
""
],
[
"Gill",
"C.",
""
],
[
"Goetz",
"E.",
""
],
[
"Goggin",
"L. M.",
""
],
[
"González",
"G.",
""
],
[
"Gorodetsky",
"M. L.",
""
],
[
"Goßler",
"S.",
""
],
[
"Gouaty",
"R.",
""
],
[
"Graef",
"C.",
""
],
[
"Granata",
"M.",
""
],
[
"Grant",
"A.",
""
],
[
"Gras",
"S.",
""
],
[
"Gray",
"C.",
""
],
[
"Greenhalgh",
"R. J. S.",
""
],
[
"Gretarsson",
"A. M.",
""
],
[
"Greverie",
"C.",
""
],
[
"Grosso",
"R.",
""
],
[
"Grote",
"H.",
""
],
[
"Grunewald",
"S.",
""
],
[
"Guidi",
"G. M.",
""
],
[
"Gustafson",
"E. K.",
""
],
[
"Gustafson",
"R.",
""
],
[
"Hage",
"B.",
""
],
[
"Hall",
"P.",
""
],
[
"Hallam",
"J. M.",
""
],
[
"Hammer",
"D.",
""
],
[
"Hammond",
"G.",
""
],
[
"Hanks",
"J.",
""
],
[
"Hanna",
"C.",
""
],
[
"Hanson",
"J.",
""
],
[
"Harms",
"J.",
""
],
[
"Harry",
"G. M.",
""
],
[
"Harry",
"I. W.",
""
],
[
"Harstad",
"E. D.",
""
],
[
"Haughian",
"K.",
""
],
[
"Hayama",
"K.",
""
],
[
"Heefner",
"J.",
""
],
[
"Heitmann",
"H.",
""
],
[
"Hello",
"P.",
""
],
[
"Heng",
"I. S.",
""
],
[
"Heptonstall",
"A.",
""
],
[
"Hewitson",
"M.",
""
],
[
"Hild",
"S.",
""
],
[
"Hirose",
"E.",
""
],
[
"Hoak",
"D.",
""
],
[
"Hodge",
"K. A.",
""
],
[
"Holt",
"K.",
""
],
[
"Hosken",
"D. J.",
""
],
[
"Hough",
"J.",
""
],
[
"Howell",
"E.",
""
],
[
"Hoyland",
"D.",
""
],
[
"Huet",
"D.",
""
],
[
"Hughey",
"B.",
""
],
[
"Husa",
"S.",
""
],
[
"Huttner",
"S. H.",
""
],
[
"Huynh--Dinh",
"T.",
""
],
[
"Ingram",
"D. R.",
""
],
[
"Inta",
"R.",
""
],
[
"Isogai",
"T.",
""
],
[
"Ivanov",
"A.",
""
],
[
"Jaranowski",
"P.",
""
],
[
"Johnson",
"W. W.",
""
],
[
"Jones",
"D. I.",
""
],
[
"Jones",
"G.",
""
],
[
"Jones",
"R.",
""
],
[
"Ju",
"L.",
""
],
[
"Kalmus",
"P.",
""
],
[
"Kalogera",
"V.",
""
],
[
"Kandhasamy",
"S.",
""
],
[
"Kanner",
"J.",
""
],
[
"Katsavounidis",
"E.",
""
],
[
"Kawabe",
"K.",
""
],
[
"Kawamura",
"S.",
""
],
[
"Kawazoe",
"F.",
""
],
[
"Kells",
"W.",
""
],
[
"Keppel",
"D. G.",
""
],
[
"Khalaidovski",
"A.",
""
],
[
"Khalili",
"F. Y.",
""
],
[
"Khazanov",
"E. A.",
""
],
[
"Kim",
"C.",
""
],
[
"Kim",
"H.",
""
],
[
"King",
"P. J.",
""
],
[
"Kinzel",
"D. L.",
""
],
[
"Kissel",
"J. S.",
""
],
[
"Klimenko",
"S.",
""
],
[
"Kondrashov",
"V.",
""
],
[
"Kopparapu",
"R.",
""
],
[
"Koranda",
"S.",
""
],
[
"Kowalska",
"I.",
""
],
[
"Kozak",
"D.",
""
],
[
"Krause",
"T.",
""
],
[
"Kringel",
"V.",
""
],
[
"Krishnamurthy",
"S.",
""
],
[
"Krishnan",
"B.",
""
],
[
"Królak",
"A.",
""
],
[
"Kuehn",
"G.",
""
],
[
"Kullman",
"J.",
""
],
[
"Kumar",
"R.",
""
],
[
"Kwee",
"P.",
""
],
[
"Landry",
"M.",
""
],
[
"Lang",
"M.",
""
],
[
"Lantz",
"B.",
""
],
[
"Lastzka",
"N.",
""
],
[
"Lazzarini",
"A.",
""
],
[
"Leaci",
"P.",
""
],
[
"Leong",
"J.",
""
],
[
"Leonor",
"I.",
""
],
[
"Leroy",
"N.",
""
],
[
"Letendre",
"N.",
""
],
[
"Li",
"J.",
""
],
[
"Li",
"T. G. F.",
""
],
[
"Lin",
"H.",
""
],
[
"Lindquist",
"P. E.",
""
],
[
"Lockerbie",
"N. A.",
""
],
[
"Lodhia",
"D.",
""
],
[
"Lorenzini",
"M.",
""
],
[
"Loriette",
"V.",
""
],
[
"Lormand",
"M.",
""
],
[
"Losurdo",
"G.",
""
],
[
"Lu",
"P.",
""
],
[
"Luan",
"J.",
""
],
[
"Lubinski",
"M.",
""
],
[
"Lucianetti",
"A.",
""
],
[
"Lück",
"H.",
""
],
[
"Lundgren",
"A.",
""
],
[
"Machenschalk",
"B.",
""
],
[
"MacInnis",
"M.",
""
],
[
"Mackowski",
"J. M.",
""
],
[
"Mageswaran",
"M.",
""
],
[
"Mailand",
"K.",
""
],
[
"Majorana",
"E.",
""
],
[
"Mak",
"C.",
""
],
[
"Man",
"N.",
""
],
[
"Mandel",
"I.",
""
],
[
"Mandic",
"V.",
""
],
[
"Mantovani",
"M.",
""
],
[
"Marchesoni",
"F.",
""
],
[
"Marion",
"F.",
""
],
[
"Márka",
"S.",
""
],
[
"Márka",
"Z.",
""
],
[
"Maros",
"E.",
""
],
[
"Marque",
"J.",
""
],
[
"Martelli",
"F.",
""
],
[
"Martin",
"I. W.",
""
],
[
"Martin",
"R. M.",
""
],
[
"Marx",
"J. N.",
""
],
[
"Mason",
"K.",
""
],
[
"Masserot",
"A.",
""
],
[
"Matichard",
"F.",
""
],
[
"Matone",
"L.",
""
],
[
"Matzner",
"R. A.",
""
],
[
"Mavalvala",
"N.",
""
],
[
"McCarthy",
"R.",
""
],
[
"McClelland",
"D. E.",
""
],
[
"McGuire",
"S. C.",
""
],
[
"McIntyre",
"G.",
""
],
[
"McIvor",
"G.",
""
],
[
"McKechan",
"D. J. A.",
""
],
[
"Meadors",
"G.",
""
],
[
"Mehmet",
"M.",
""
],
[
"Meier",
"T.",
""
],
[
"Melatos",
"A.",
""
],
[
"Melissinos",
"A. C.",
""
],
[
"Mendell",
"G.",
""
],
[
"Menéndez",
"D. F.",
""
],
[
"Mercer",
"R. A.",
""
],
[
"Merill",
"L.",
""
],
[
"Meshkov",
"S.",
""
],
[
"Messenger",
"C.",
""
],
[
"Meyer",
"M. S.",
""
],
[
"Miao",
"H.",
""
],
[
"Michel",
"C.",
""
],
[
"Milano",
"L.",
""
],
[
"Miller",
"J.",
""
],
[
"Minenkov",
"Y.",
""
],
[
"Mino",
"Y.",
""
],
[
"Mitra",
"S.",
""
],
[
"Mitrofanov",
"V. P.",
""
],
[
"Mitselmakher",
"G.",
""
],
[
"Mittleman",
"R.",
""
],
[
"Moe",
"B.",
""
],
[
"Mohan",
"M.",
""
],
[
"Mohanty",
"S. D.",
""
],
[
"Mohapatra",
"S. R. P.",
""
],
[
"Moraru",
"D.",
""
],
[
"Moreau",
"J.",
""
],
[
"Moreno",
"G.",
""
],
[
"Morgado",
"N.",
""
],
[
"Morgia",
"A.",
""
],
[
"Morioka",
"T.",
""
],
[
"Mors",
"K.",
""
],
[
"Mosca",
"S.",
""
],
[
"Moscatelli",
"V.",
""
],
[
"Mossavi",
"K.",
""
],
[
"Mours",
"B.",
""
],
[
"MowLowry",
"C.",
""
],
[
"Mueller",
"G.",
""
],
[
"Mukherjee",
"S.",
""
],
[
"Mullavey",
"A.",
""
],
[
"Müller-Ebhardt",
"H.",
""
],
[
"Munch",
"J.",
""
],
[
"Murray",
"P. G.",
""
],
[
"Nash",
"T.",
""
],
[
"Nawrodt",
"R.",
""
],
[
"Nelson",
"J.",
""
],
[
"Neri",
"I.",
""
],
[
"Newton",
"G.",
""
],
[
"Nishizawa",
"A.",
""
],
[
"Nocera",
"F.",
""
],
[
"Nolting",
"D.",
""
],
[
"Ochsner",
"E.",
""
],
[
"O'Dell",
"J.",
""
],
[
"Ogin",
"G. H.",
""
],
[
"Oldenburg",
"R. G.",
""
],
[
"O'Reilly",
"B.",
""
],
[
"O'Shaughnessy",
"R.",
""
],
[
"Osthelder",
"C.",
""
],
[
"Ottaway",
"D. J.",
""
],
[
"Ottens",
"R. S.",
""
],
[
"Overmier",
"H.",
""
],
[
"Owen",
"B. J.",
""
],
[
"Page",
"A.",
""
],
[
"Pagliaroli",
"G.",
""
],
[
"Palladino",
"L.",
""
],
[
"Palomba",
"C.",
""
],
[
"Pan",
"Y.",
""
],
[
"Pankow",
"C.",
""
],
[
"Paoletti",
"F.",
""
],
[
"Papa",
"M. A.",
""
],
[
"Pardi",
"S.",
""
],
[
"Pareja",
"M.",
""
],
[
"Parisi",
"M.",
""
],
[
"Pasqualetti",
"A.",
""
],
[
"Passaquieti",
"R.",
""
],
[
"Passuello",
"D.",
""
],
[
"Patel",
"P.",
""
],
[
"Pedraza",
"M.",
""
],
[
"Pekowsky",
"L.",
""
],
[
"Penn",
"S.",
""
],
[
"Peralta",
"C.",
""
],
[
"Perreca",
"A.",
""
],
[
"Persichetti",
"G.",
""
],
[
"Pichot",
"M.",
""
],
[
"Pickenpack",
"M.",
""
],
[
"Piergiovanni",
"F.",
""
],
[
"Pietka",
"M.",
""
],
[
"Pinard",
"L.",
""
],
[
"Pinto",
"I. M.",
""
],
[
"Pitkin",
"M.",
""
],
[
"Pletsch",
"H. J.",
""
],
[
"Plissi",
"M. V.",
""
],
[
"Poggiani",
"R.",
""
],
[
"Postiglione",
"F.",
""
],
[
"Prato",
"M.",
""
],
[
"Predoi",
"V.",
""
],
[
"Price",
"L. R.",
""
],
[
"Prijatelj",
"M.",
""
],
[
"Principe",
"M.",
""
],
[
"Privitera",
"S.",
""
],
[
"Prix",
"R.",
""
],
[
"Prodi",
"G. A.",
""
],
[
"Prokhorov",
"L.",
""
],
[
"Puncken",
"O.",
""
],
[
"Punturo",
"M.",
""
],
[
"Puppo",
"P.",
""
],
[
"Quetschke",
"V.",
""
],
[
"Raab",
"F. J.",
""
],
[
"Rabaste",
"O.",
""
],
[
"Rabeling",
"D. S.",
""
],
[
"Radke",
"T.",
""
],
[
"Radkins",
"H.",
""
],
[
"Raffai",
"P.",
""
],
[
"Rakhmanov",
"M.",
""
],
[
"Rankins",
"B.",
""
],
[
"Rapagnani",
"P.",
""
],
[
"Raymond",
"V.",
""
],
[
"Re",
"V.",
""
],
[
"Reed",
"C. M.",
""
],
[
"Reed",
"T.",
""
],
[
"Regimbau",
"T.",
""
],
[
"Reid",
"S.",
""
],
[
"Reitze",
"D. H.",
""
],
[
"Ricci",
"F.",
""
],
[
"Riesen",
"R.",
""
],
[
"Riles",
"K.",
""
],
[
"Roberts",
"P.",
""
],
[
"Robertson",
"N. A.",
""
],
[
"Robinet",
"F.",
""
],
[
"Robinson",
"C.",
""
],
[
"Robinson",
"E. L.",
""
],
[
"Rocchi",
"A.",
""
],
[
"Roddy",
"S.",
""
],
[
"Röver",
"C.",
""
],
[
"Rolland",
"L.",
""
],
[
"Rollins",
"J.",
""
],
[
"Romano",
"J. D.",
""
],
[
"Romano",
"R.",
""
],
[
"Romie",
"J. H.",
""
],
[
"Rosińska",
"D.",
""
],
[
"Rowan",
"S.",
""
],
[
"Rüdiger",
"A.",
""
],
[
"Ruggi",
"P.",
""
],
[
"Ryan",
"K.",
""
],
[
"Sakata",
"S.",
""
],
[
"Sakosky",
"M.",
""
],
[
"Salemi",
"F.",
""
],
[
"Sammut",
"L.",
""
],
[
"de la Jordana",
"L. Sancho",
""
],
[
"Sandberg",
"V.",
""
],
[
"Sannibale",
"V.",
""
],
[
"Santamaría",
"L.",
""
],
[
"Santostasi",
"G.",
""
],
[
"Saraf",
"S.",
""
],
[
"Sassolas",
"B.",
""
],
[
"Sathyaprakash",
"B. S.",
""
],
[
"Sato",
"S.",
""
],
[
"Satterthwaite",
"M.",
""
],
[
"Saulson",
"P. R.",
""
],
[
"Savage",
"R.",
""
],
[
"Schilling",
"R.",
""
],
[
"Schnabel",
"R.",
""
],
[
"Schofield",
"R.",
""
],
[
"Schulz",
"B.",
""
],
[
"Schutz",
"B. F.",
""
],
[
"Schwinberg",
"P.",
""
],
[
"Scott",
"J.",
""
],
[
"Scott",
"S. M.",
""
],
[
"Searle",
"A. C.",
""
],
[
"Seifert",
"F.",
""
],
[
"Sellers",
"D.",
""
],
[
"Sengupta",
"A. S.",
""
],
[
"Sentenac",
"D.",
""
],
[
"Sergeev",
"A.",
""
],
[
"Shaddock",
"D.",
""
],
[
"Shapiro",
"B.",
""
],
[
"Shawhan",
"P.",
""
],
[
"Shoemaker",
"D. H.",
""
],
[
"Sibley",
"A.",
""
],
[
"Siemens",
"X.",
""
],
[
"Sigg",
"D.",
""
],
[
"Singer",
"A.",
""
],
[
"Sintes",
"A. M.",
""
],
[
"Skelton",
"G.",
""
],
[
"Slagmolen",
"B. J. J.",
""
],
[
"Slutsky",
"J.",
""
],
[
"Smith",
"J. R.",
""
],
[
"Smith",
"M. R.",
""
],
[
"Smith",
"N. D.",
""
],
[
"Somiya",
"K.",
""
],
[
"Sorazu",
"B.",
""
],
[
"Speirits",
"F. C.",
""
],
[
"Stein",
"A. J.",
""
],
[
"Stein",
"L. C.",
""
],
[
"Steinlechner",
"S.",
""
],
[
"Steplewski",
"S.",
""
],
[
"Stochino",
"A.",
""
],
[
"Stone",
"R.",
""
],
[
"Strain",
"K. A.",
""
],
[
"Strigin",
"S.",
""
],
[
"Stroeer",
"A.",
""
],
[
"Sturani",
"R.",
""
],
[
"Stuver",
"A. L.",
""
],
[
"Summerscales",
"T. Z.",
""
],
[
"Sung",
"M.",
""
],
[
"Susmithan",
"S.",
""
],
[
"Sutton",
"P. J.",
""
],
[
"Swinkels",
"B.",
""
],
[
"Talukder",
"D.",
""
],
[
"Tanner",
"D. B.",
""
],
[
"Tarabrin",
"S. P.",
""
],
[
"Taylor",
"J. R.",
""
],
[
"Taylor",
"R.",
""
],
[
"Thomas",
"P.",
""
],
[
"Thorne",
"K. A.",
""
],
[
"Thorne",
"K. S.",
""
],
[
"Thrane",
"E.",
""
],
[
"Thüring",
"A.",
""
],
[
"Titsler",
"C.",
""
],
[
"Tokmakov",
"K. V.",
""
],
[
"Toncelli",
"A.",
""
],
[
"Tonelli",
"M.",
""
],
[
"Torres",
"C.",
""
],
[
"Torrie",
"C. I.",
""
],
[
"Tournefier",
"E.",
""
],
[
"Travasso",
"F.",
""
],
[
"Traylor",
"G.",
""
],
[
"Trias",
"M.",
""
],
[
"Trummer",
"J.",
""
],
[
"Tseng",
"K.",
""
],
[
"Ugolini",
"D.",
""
],
[
"Urbanek",
"K.",
""
],
[
"Vahlbruch",
"H.",
""
],
[
"Vaishnav",
"B.",
""
],
[
"Vajente",
"G.",
""
],
[
"Vallisneri",
"M.",
""
],
[
"Brand",
"J. F. J. van den",
""
],
[
"Broeck",
"C. Van Den",
""
],
[
"van der Putten",
"S.",
""
],
[
"van der Sluys",
"M. V.",
""
],
[
"van Veggel",
"A. A.",
""
],
[
"Vass",
"S.",
""
],
[
"Vaulin",
"R.",
""
],
[
"Vavoulidis",
"M.",
""
],
[
"Vecchio",
"A.",
""
],
[
"Vedovato",
"G.",
""
],
[
"Veitch",
"J.",
""
],
[
"Veitch",
"P. J.",
""
],
[
"Veltkamp",
"C.",
""
],
[
"Verkindt",
"D.",
""
],
[
"Vetrano",
"F.",
""
],
[
"Viceré",
"A.",
""
],
[
"Villar",
"A.",
""
],
[
"Vinet",
"J. -Y.",
""
],
[
"Vocca",
"H.",
""
],
[
"Vorvick",
"C.",
""
],
[
"Vyachanin",
"S. P.",
""
],
[
"Waldman",
"S. J.",
""
],
[
"Wallace",
"L.",
""
],
[
"Wanner",
"A.",
""
],
[
"Ward",
"R. L.",
""
],
[
"Was",
"M.",
""
],
[
"Wei",
"P.",
""
],
[
"Weinert",
"M.",
""
],
[
"Weinstein",
"A. J.",
""
],
[
"Weiss",
"R.",
""
],
[
"Wen",
"L.",
""
],
[
"Wen",
"S.",
""
],
[
"Wessels",
"P.",
""
],
[
"West",
"M.",
""
],
[
"Westphal",
"T.",
""
],
[
"Wette",
"K.",
""
],
[
"Whelan",
"J. T.",
""
],
[
"Whitcomb",
"S. E.",
""
],
[
"White",
"D. J.",
""
],
[
"Whiting",
"B. F.",
""
],
[
"Wilkinson",
"C.",
""
],
[
"Willems",
"P. A.",
""
],
[
"Williams",
"L.",
""
],
[
"Willke",
"B.",
""
],
[
"Winkelmann",
"L.",
""
],
[
"Winkler",
"W.",
""
],
[
"Wipf",
"C. C.",
""
],
[
"Wiseman",
"A. G.",
""
],
[
"Woan",
"G.",
""
],
[
"Wooley",
"R.",
""
],
[
"Worden",
"J.",
""
],
[
"Yakushin",
"I.",
""
],
[
"Yamamoto",
"H.",
""
],
[
"Yamamoto",
"K.",
""
],
[
"Yeaton-Massey",
"D.",
""
],
[
"Yoshida",
"S.",
""
],
[
"Yu",
"P. P.",
""
],
[
"Yvert",
"M.",
""
],
[
"Zanolin",
"M.",
""
],
[
"Zhang",
"L.",
""
],
[
"Zhang",
"Z.",
""
],
[
"Zhao",
"C.",
""
],
[
"Zotov",
"N.",
""
],
[
"Zucker",
"M. E.",
""
],
[
"Zweizig",
"J.",
""
],
[
"Belczynski",
"K.",
""
]
] | We summarize the sensitivity achieved by the LIGO and Virgo gravitational wave detectors for compact binary coalescence (CBC) searches during LIGO's fifth science run and Virgo's first science run. We present noise spectral density curves for each of the four detectors that operated during these science runs which are representative of the typical performance achieved by the detectors for CBC searches. These spectra are intended for release to the public as a summary of detector performance for CBC searches during these science runs. |
0912.5384 | Robert Littlejohn | Hal M. Haggard and Robert G. Littlejohn | Asymptotics of the Wigner 9j symbol | 17 pages, 7 figures | Class.Quant.Grav.27:135010,2010 | 10.1088/0264-9381/27/13/135010 | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We present the asymptotic formula for the Wigner 9j-symbol, valid when all
quantum numbers are large, in the classically allowed region. As in the
Ponzano-Regge formula for the 6j-symbol, the action is expressed in terms of
lengths of edges and dihedral angles of a geometrical figure, but the angles
require care in definition. Rules are presented for converting spin networks
into the associated geometrical figures. The amplitude is expressed as the
determinant of a 2x2 matrix of Poisson brackets. The 9j-symbol possesses
caustics associated with the fold and elliptic and hyperbolic umbilic
catastrophes. The asymptotic formula obeys the exact symmetries of the
9j-symbol.
| [
{
"created": "Tue, 29 Dec 2009 23:06:08 GMT",
"version": "v1"
}
] | 2010-05-25 | [
[
"Haggard",
"Hal M.",
""
],
[
"Littlejohn",
"Robert G.",
""
]
] | We present the asymptotic formula for the Wigner 9j-symbol, valid when all quantum numbers are large, in the classically allowed region. As in the Ponzano-Regge formula for the 6j-symbol, the action is expressed in terms of lengths of edges and dihedral angles of a geometrical figure, but the angles require care in definition. Rules are presented for converting spin networks into the associated geometrical figures. The amplitude is expressed as the determinant of a 2x2 matrix of Poisson brackets. The 9j-symbol possesses caustics associated with the fold and elliptic and hyperbolic umbilic catastrophes. The asymptotic formula obeys the exact symmetries of the 9j-symbol. |
2009.10133 | Jorge Ananias Neto | Everton M. C. Abreu and Jorge Ananias Neto | Barrow black hole corrected-entropy model and Tsallis nonextensivity | 10 pages. To be published in PLB | null | 10.1016/j.physletb.2020.135805 | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The quantum scenario concerning Hawking radiation, gives us a precious clue
that a black hole has its temperature directly connected to its area gravity
and that its entropy is proportional to the horizon area. These results have
shown that there exist a deep association between thermodynamics and gravity.
The recently introduced Barrow formulation of back holes entropy, influenced by
the spacetime geometry, shows the quantum fluctuations effects through Barrow
exponent, $\Delta$, where $\Delta=0$ represents the usual spacetime and its
maximum value, $\Delta=1$, characterizes a fractal spacetime. The quantum
fluctuations are responsible for such fractality. Loop quantum gravity approach
provided the logarithmic corrections to the entropy. This correction arises
from quantum and thermal equilibrium fluctuations. In this paper we have
analyzed the nonextensive thermodynamical effects of the quantum fluctuations
upon the geometry of a Barrow black hole. We discussed the Tsallis' formulation
of this logarithmically corrected Barrow entropy to construct the equipartition
law. Besides, we obtained a master equation that provides the equipartition law
for any value of the Tsallis $q$-parameter and we analyzed several different
scenarios. After that, the heat capacity were calculated and the thermal
stability analysis was carried out as a function of the main parameters,
namely, one of the so-called pre-factors, $q$ and $\Delta$.
| [
{
"created": "Mon, 21 Sep 2020 18:54:44 GMT",
"version": "v1"
}
] | 2020-10-28 | [
[
"Abreu",
"Everton M. C.",
""
],
[
"Neto",
"Jorge Ananias",
""
]
] | The quantum scenario concerning Hawking radiation, gives us a precious clue that a black hole has its temperature directly connected to its area gravity and that its entropy is proportional to the horizon area. These results have shown that there exist a deep association between thermodynamics and gravity. The recently introduced Barrow formulation of back holes entropy, influenced by the spacetime geometry, shows the quantum fluctuations effects through Barrow exponent, $\Delta$, where $\Delta=0$ represents the usual spacetime and its maximum value, $\Delta=1$, characterizes a fractal spacetime. The quantum fluctuations are responsible for such fractality. Loop quantum gravity approach provided the logarithmic corrections to the entropy. This correction arises from quantum and thermal equilibrium fluctuations. In this paper we have analyzed the nonextensive thermodynamical effects of the quantum fluctuations upon the geometry of a Barrow black hole. We discussed the Tsallis' formulation of this logarithmically corrected Barrow entropy to construct the equipartition law. Besides, we obtained a master equation that provides the equipartition law for any value of the Tsallis $q$-parameter and we analyzed several different scenarios. After that, the heat capacity were calculated and the thermal stability analysis was carried out as a function of the main parameters, namely, one of the so-called pre-factors, $q$ and $\Delta$. |
gr-qc/0702087 | Raul Horvat | R. Horvat | Renormalization-group running cosmologies and the generalized second law | 8 pages, final version to appear in Phys. Lett. B | Phys.Lett.B648:374-377,2007 | 10.1016/j.physletb.2007.03.037 | null | gr-qc astro-ph hep-th | null | We explore some thermodynamical consequences of accelerated universes driven
by a running cosmological constant (CC) from the renormalization group (RG).
Application of the generalized second law (GSL) of gravitational thermodynamics
to a framework where the running of the CC goes at the expense of energy
transfer between vacuum and matter, strongly restricts the mass spectrum of a
(hypothetical) theory controlling the CC running. We find that quantum effects
driving the running of the CC should be dominated by a trans-planckian mass
field, in marked contrast with the GUT-scale upper mass bound obtained by
analyzing density perturbations for the running CC. The model shows compliance
with the holographic principle.
| [
{
"created": "Thu, 15 Feb 2007 11:21:00 GMT",
"version": "v1"
},
{
"created": "Mon, 19 Feb 2007 16:07:24 GMT",
"version": "v2"
},
{
"created": "Thu, 22 Mar 2007 09:14:32 GMT",
"version": "v3"
}
] | 2008-11-26 | [
[
"Horvat",
"R.",
""
]
] | We explore some thermodynamical consequences of accelerated universes driven by a running cosmological constant (CC) from the renormalization group (RG). Application of the generalized second law (GSL) of gravitational thermodynamics to a framework where the running of the CC goes at the expense of energy transfer between vacuum and matter, strongly restricts the mass spectrum of a (hypothetical) theory controlling the CC running. We find that quantum effects driving the running of the CC should be dominated by a trans-planckian mass field, in marked contrast with the GUT-scale upper mass bound obtained by analyzing density perturbations for the running CC. The model shows compliance with the holographic principle. |
gr-qc/9904032 | T. Damour | T. Damour | Equivalence Principle and Clocks | 7 pages, latex, uses moriond.sty, to appear in the Proceedings of the
34th Rencontres de Moriond, "Gravitational Waves and Experimental Gravity",
January 1999 | null | null | IHES/P/99/11 | gr-qc | null | String theory suggests the existence of gravitational-strength scalar fields
("dilaton" and "moduli") whose couplings to matter violate the equivalence
principle. This provides a new motivation for high-precision clock experiments,
as well as a generic theoretical framework for analyzing their significance.
| [
{
"created": "Wed, 14 Apr 1999 13:09:18 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Damour",
"T.",
""
]
] | String theory suggests the existence of gravitational-strength scalar fields ("dilaton" and "moduli") whose couplings to matter violate the equivalence principle. This provides a new motivation for high-precision clock experiments, as well as a generic theoretical framework for analyzing their significance. |
1003.5640 | Alexander Kouretsis | A.P.Kouretsis, M.Stathakopoulos and P.C.Stavrinos | Imperfect fluids, Lorentz violations and Finsler Cosmology | v1:16 pages v2: extended version; section, several comments,
clarifications and references added; to appear on prd | Phys.Rev.D82:064035,2010 | 10.1103/PhysRevD.82.064035 | null | gr-qc hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We construct a cosmological toy model based on a Finslerian structure of
space-time. In particular, we are interested in a specific Finslerian Lorentz
violating theory based on a curved version of Cohen and Glashow's Very Special
Relativity. The osculation of a Finslerian manifold to a Riemannian leads to
the limit of Relativistic Cosmology, for a specified observer. A modified flat
FRW cosmology is produced. The analogue of a zero energy particle unfolds some
special properties of the dynamics. The kinematical equations of motion are
affected by local anisotropies. Seeds of Lorentz Violations may trigger density
inhomogeneities to the cosmological fluid.
| [
{
"created": "Mon, 29 Mar 2010 19:02:41 GMT",
"version": "v1"
},
{
"created": "Mon, 6 Sep 2010 14:42:51 GMT",
"version": "v2"
}
] | 2014-11-20 | [
[
"Kouretsis",
"A. P.",
""
],
[
"Stathakopoulos",
"M.",
""
],
[
"Stavrinos",
"P. C.",
""
]
] | We construct a cosmological toy model based on a Finslerian structure of space-time. In particular, we are interested in a specific Finslerian Lorentz violating theory based on a curved version of Cohen and Glashow's Very Special Relativity. The osculation of a Finslerian manifold to a Riemannian leads to the limit of Relativistic Cosmology, for a specified observer. A modified flat FRW cosmology is produced. The analogue of a zero energy particle unfolds some special properties of the dynamics. The kinematical equations of motion are affected by local anisotropies. Seeds of Lorentz Violations may trigger density inhomogeneities to the cosmological fluid. |
1212.0432 | Ahmet Baykal | Ahmet Baykal | Energy definition for quadratic curvature gravities | 7 pages | Phys. Rev. D 86, 127501 (2012) | 10.1103/PhysRevD.86.127501 | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A conserved current for generic quadratic curvature gravitational models is
defined, and it is shown that, at the linearized level, it corresponds to the
Deser-Tekin charges. An explicit expression for the charge for new massive
gravity in three dimensions is given. Some implications of the linearized
equations are discussed.
| [
{
"created": "Mon, 3 Dec 2012 16:20:08 GMT",
"version": "v1"
}
] | 2012-12-04 | [
[
"Baykal",
"Ahmet",
""
]
] | A conserved current for generic quadratic curvature gravitational models is defined, and it is shown that, at the linearized level, it corresponds to the Deser-Tekin charges. An explicit expression for the charge for new massive gravity in three dimensions is given. Some implications of the linearized equations are discussed. |
1604.08039 | Sudipto Roy | Sudipto Roy, Mohsin Islam | A Study of Cosmic Expansion Generated by Non-conservation of Matter in
the Framework of Brans-Dicke Theory | 12 pages, 8 figures | International Journal of Physics and Mathematical Sciences, Volume
6, Number 2, pages 1-10, 2016 | null | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The present study, on the expansion of universe, is based on an assumption
regarding the possibility of inter-conversion between matter and dark energy,
through some interaction of matter with the scalar field in the framework of
Brans-Dicke theory. The field equations for a spatially flat space-time have
been solved using an empirical dependence of scalar field parameter upon the
scale factor. To represent the behaviour regarding the non-conservation of
matter, a function, expressed in terms of the Hubble parameter, has been
empirically incorporated into the field equations. Their solution shows that,
this function, whose value is proportional to the matter content of the
universe, decreases monotonically with time. This matter-field interaction
generates late time acceleration, causing the deceleration parameter to change
its sign from positive to negative. Time dependence of the proportion of dark
energy component of the universe has been determined and shown graphically.
Time variation of gravitational constant and the Brans-Dicke dimensionless
parameter has been analyzed in the present study. The rate of generation of
dark energy from matter has been found to affect the time variations of
deceleration parameter and gravitational constant.
| [
{
"created": "Mon, 25 Apr 2016 20:00:11 GMT",
"version": "v1"
}
] | 2017-11-07 | [
[
"Roy",
"Sudipto",
""
],
[
"Islam",
"Mohsin",
""
]
] | The present study, on the expansion of universe, is based on an assumption regarding the possibility of inter-conversion between matter and dark energy, through some interaction of matter with the scalar field in the framework of Brans-Dicke theory. The field equations for a spatially flat space-time have been solved using an empirical dependence of scalar field parameter upon the scale factor. To represent the behaviour regarding the non-conservation of matter, a function, expressed in terms of the Hubble parameter, has been empirically incorporated into the field equations. Their solution shows that, this function, whose value is proportional to the matter content of the universe, decreases monotonically with time. This matter-field interaction generates late time acceleration, causing the deceleration parameter to change its sign from positive to negative. Time dependence of the proportion of dark energy component of the universe has been determined and shown graphically. Time variation of gravitational constant and the Brans-Dicke dimensionless parameter has been analyzed in the present study. The rate of generation of dark energy from matter has been found to affect the time variations of deceleration parameter and gravitational constant. |
1103.0983 | Umberto Cannella | Umberto Cannella | Effective Field Theory Methods in Gravitational Physics and Tests of
Gravity | This PhD Thesis has been conducted at the University of Geneva
(Switzerland) under the direction of Professor Michele Maggiore and the
codirection of Doctor Riccardo Sturani. Version 2: abstract slightly changed;
one typo corrected; layout issue fixed | null | null | null | gr-qc astro-ph.HE hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this PhD thesis I make use of the "Effective Field Theory of Gravity for
Extended Objects" by Goldberger and Rothstein in order to investigate theories
of gravity and to take a different point of view on the physical information
that can be extracted from experiments. In the first work I present, I study a
scalar-tensor theory of gravity and I address the renormalization of the
energy-momentum tensor for point-like and string-like sources. The second and
third study I report are set in the context of testing gravity. So far
experiments have probed dynamical regimes only up to order (v/c)^5 in the
post-Newtonian expansion, which corresponds to the very first term of the
radiative sector in General Relativity. In contrast, by means of
gravitational-wave astronomy, one aims at testing General Relativity up to
(v/c)^(12)! It is then relevant to envisage testing frameworks which are
appropriate to this strong-field/radiative regime. In the last two chapters of
this thesis a new such framework is presented. Using the effective field theory
approach, General Relativity non-linearities are described by Feynman diagrams
in which classical gravitons interact with matter sources and among themselves.
Tagging the self-interaction vertices of gravitons with parameters it is
possible, for example, to translate the measure of the period decay of
Hulse-Taylor pulsar in a constraint on the three-graviton vertex at the 0.1%
level; for comparison, LEP constraints on the triple-gauge-boson couplings of
weak interactions are accurate at 3%. With future observations of gravitational
waves, higher order graviton vertices can in principle be constrained through a
Fisher matrix analysis.
| [
{
"created": "Sat, 5 Mar 2011 20:34:05 GMT",
"version": "v1"
},
{
"created": "Tue, 19 Apr 2011 16:11:32 GMT",
"version": "v2"
}
] | 2015-03-19 | [
[
"Cannella",
"Umberto",
""
]
] | In this PhD thesis I make use of the "Effective Field Theory of Gravity for Extended Objects" by Goldberger and Rothstein in order to investigate theories of gravity and to take a different point of view on the physical information that can be extracted from experiments. In the first work I present, I study a scalar-tensor theory of gravity and I address the renormalization of the energy-momentum tensor for point-like and string-like sources. The second and third study I report are set in the context of testing gravity. So far experiments have probed dynamical regimes only up to order (v/c)^5 in the post-Newtonian expansion, which corresponds to the very first term of the radiative sector in General Relativity. In contrast, by means of gravitational-wave astronomy, one aims at testing General Relativity up to (v/c)^(12)! It is then relevant to envisage testing frameworks which are appropriate to this strong-field/radiative regime. In the last two chapters of this thesis a new such framework is presented. Using the effective field theory approach, General Relativity non-linearities are described by Feynman diagrams in which classical gravitons interact with matter sources and among themselves. Tagging the self-interaction vertices of gravitons with parameters it is possible, for example, to translate the measure of the period decay of Hulse-Taylor pulsar in a constraint on the three-graviton vertex at the 0.1% level; for comparison, LEP constraints on the triple-gauge-boson couplings of weak interactions are accurate at 3%. With future observations of gravitational waves, higher order graviton vertices can in principle be constrained through a Fisher matrix analysis. |
0812.0428 | Prasanta Mahato Prin. | Prasanta Mahato | Torsion and Axial Current | 13 pages, no figure | ICFAI Univ. Jour. of Phys.,2,(2009),92-104 | null | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The role of torsion and a scalar field $\phi$ in gravitation, especially, in
the presence of a Dirac field in the background of a particular class of the
Riemann-Cartan geometry is considered here. Recently, a Lagrangian density with
Lagrange multipliers has been proposed by the author which has been obtained by
picking some particular terms from the SO(4,1) Pontryagin density, where the
scalar field $\phi$ causes the de Sitter connection to have the proper
dimension of a gauge field. In this formalism, conserved axial vector matter
current can be constructed, irrespective of any gauge choice, in any manifold
having arbitrary background geometry. This current is not a Noether current.
| [
{
"created": "Tue, 2 Dec 2008 04:52:39 GMT",
"version": "v1"
},
{
"created": "Sat, 6 Dec 2008 17:16:40 GMT",
"version": "v2"
}
] | 2009-09-04 | [
[
"Mahato",
"Prasanta",
""
]
] | The role of torsion and a scalar field $\phi$ in gravitation, especially, in the presence of a Dirac field in the background of a particular class of the Riemann-Cartan geometry is considered here. Recently, a Lagrangian density with Lagrange multipliers has been proposed by the author which has been obtained by picking some particular terms from the SO(4,1) Pontryagin density, where the scalar field $\phi$ causes the de Sitter connection to have the proper dimension of a gauge field. In this formalism, conserved axial vector matter current can be constructed, irrespective of any gauge choice, in any manifold having arbitrary background geometry. This current is not a Noether current. |
1012.0953 | Francisco Lobo | Nadiezhda Montelongo Garc\'ia, Tiberiu Harko, Francisco S. N. Lobo,
Jos\'e P. Mimoso | f(G) modified gravity and the energy conditions | 4 pages. Prepared for the proceedings of the Spanish Relativity
meeting (ERE2010), Granada, Spain, 6-10 Sep 2010 | J.Phys.Conf.Ser.314:012060,2011 | 10.1088/1742-6596/314/1/012056 | null | gr-qc astro-ph.CO hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Motivated by string/M-theory predictions that scalar field couplings with the
Gauss-Bonnet invariant, G, are essential in the appearance of non-singular
early time cosmologies, we discuss the viability of an interesting alternative
gravitational theory, namely, modified Gauss-Bonnet gravity, and present the
viability bounds arising from the energy conditions. In particular, we consider
a specific realistic form of f(G) analyzed in the literature that accounts for
the late-time cosmic acceleration and that has been found to cure the
finite-time future singularities present in the dark energy models, and further
examine the respective viability of the specific f(G) model imposed by the weak
energy condition.
| [
{
"created": "Sat, 4 Dec 2010 22:24:39 GMT",
"version": "v1"
}
] | 2015-03-17 | [
[
"García",
"Nadiezhda Montelongo",
""
],
[
"Harko",
"Tiberiu",
""
],
[
"Lobo",
"Francisco S. N.",
""
],
[
"Mimoso",
"José P.",
""
]
] | Motivated by string/M-theory predictions that scalar field couplings with the Gauss-Bonnet invariant, G, are essential in the appearance of non-singular early time cosmologies, we discuss the viability of an interesting alternative gravitational theory, namely, modified Gauss-Bonnet gravity, and present the viability bounds arising from the energy conditions. In particular, we consider a specific realistic form of f(G) analyzed in the literature that accounts for the late-time cosmic acceleration and that has been found to cure the finite-time future singularities present in the dark energy models, and further examine the respective viability of the specific f(G) model imposed by the weak energy condition. |
2301.05083 | Karim Mosani | Karim Mosani, Koushiki, Pankaj S. Joshi, Jay Verma Trivedi, and
Tapobroto Bhanja | Gravitational collapse of scalar and vector fields | null | null | null | null | gr-qc | http://creativecommons.org/licenses/by/4.0/ | We study here the unhindered gravitational collapse of spatially homogeneous
(SH) scalar fields $\phi$ with a potential $V_{s}(\phi)$, as well as vector
fields $\tilde{A}$ with a potential $V_{v}(B)$ where $B=g(\tilde{A},\tilde{A})$
and $g$ is the metric tensor. We show that in both cases, classes of potentials
exist that give rise to black holes or naked singularities depending on the
choice of the potential. The strength of the naked singularity is examined, and
they are seen to be strong, in the sense of Tipler, for a wide class of
respective potentials. We match the collapsing scalar/vector field with a
generalized Vaidya spacetime outside. We highlight that full generality is
maintained within the domain of SH scalar or vector field collapse.
| [
{
"created": "Thu, 12 Jan 2023 15:33:21 GMT",
"version": "v1"
}
] | 2023-01-13 | [
[
"Mosani",
"Karim",
""
],
[
"Koushiki",
"",
""
],
[
"Joshi",
"Pankaj S.",
""
],
[
"Trivedi",
"Jay Verma",
""
],
[
"Bhanja",
"Tapobroto",
""
]
] | We study here the unhindered gravitational collapse of spatially homogeneous (SH) scalar fields $\phi$ with a potential $V_{s}(\phi)$, as well as vector fields $\tilde{A}$ with a potential $V_{v}(B)$ where $B=g(\tilde{A},\tilde{A})$ and $g$ is the metric tensor. We show that in both cases, classes of potentials exist that give rise to black holes or naked singularities depending on the choice of the potential. The strength of the naked singularity is examined, and they are seen to be strong, in the sense of Tipler, for a wide class of respective potentials. We match the collapsing scalar/vector field with a generalized Vaidya spacetime outside. We highlight that full generality is maintained within the domain of SH scalar or vector field collapse. |
gr-qc/9812045 | Massar Serge | S. Massar and R. Parentani | Unitary and non-unitary evolution in quantum cosmology | 26 pages, latex; minor corrections, final version to appear in Phys.
Rev. D | Phys. Rev. D 59, 123519 (1999) | 10.1103/PhysRevD.59.123519 | ULB-TH/98-17 | gr-qc | null | We analyse when and why unitarity violations might occur in quantum cosmology
restricted to minisuperspace. To this end we discuss in detail backscattering
transitions between expanding and contracting solutions of the Wheeler-DeWitt
equation. We first show that upon neglecting only backscattering, one obtains
an intermediate regime in which matter evolves unitarily but which does not
correspond to any Schr\"odinger equation in a given geometry since
gravitational backreaction effects are taken into account at the quantum level.
We then show that backscattering amplitudes are exponentially smaller than
matter transition amplitudes. Both results follow from an adiabatic treatment
valid for macroscopic universes. To understand how backscattering and the
intermediate regime should be interpreted, we review the problem of electronic
transitions induced by nuclear motion since it is mathematically very similar.
In this problem, transition amplitudes are obtained from the conserved current.
The same applies to quantum cosmology and shows that the unique consistent
interpretation is based on the current when backscattering is neglected. We
then review why, in a relativistic context, backscattering is interpreted as
pair production whereas it is not in the non relativistic case. In each example
the correct interpretation is obtained by coupling the system to an external
quantum device. From the absence of such external systems in cosmology, we
conclude that backscattering does not have a unique consistent interpretation
in quantum cosmology.
| [
{
"created": "Mon, 14 Dec 1998 11:26:46 GMT",
"version": "v1"
},
{
"created": "Wed, 21 Apr 1999 07:56:16 GMT",
"version": "v2"
}
] | 2016-08-25 | [
[
"Massar",
"S.",
""
],
[
"Parentani",
"R.",
""
]
] | We analyse when and why unitarity violations might occur in quantum cosmology restricted to minisuperspace. To this end we discuss in detail backscattering transitions between expanding and contracting solutions of the Wheeler-DeWitt equation. We first show that upon neglecting only backscattering, one obtains an intermediate regime in which matter evolves unitarily but which does not correspond to any Schr\"odinger equation in a given geometry since gravitational backreaction effects are taken into account at the quantum level. We then show that backscattering amplitudes are exponentially smaller than matter transition amplitudes. Both results follow from an adiabatic treatment valid for macroscopic universes. To understand how backscattering and the intermediate regime should be interpreted, we review the problem of electronic transitions induced by nuclear motion since it is mathematically very similar. In this problem, transition amplitudes are obtained from the conserved current. The same applies to quantum cosmology and shows that the unique consistent interpretation is based on the current when backscattering is neglected. We then review why, in a relativistic context, backscattering is interpreted as pair production whereas it is not in the non relativistic case. In each example the correct interpretation is obtained by coupling the system to an external quantum device. From the absence of such external systems in cosmology, we conclude that backscattering does not have a unique consistent interpretation in quantum cosmology. |
2401.11273 | Vasilis Oikonomou | V.K. Oikonomou, Pyotr Tsyba, Olga Razina | Einstein-Gauss-Bonnet Cosmological Theories at Reheating and at the End
of the Inflationary Era | AoP accepted | null | null | null | gr-qc astro-ph.CO | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this work we study the GW170817-compatible Einstein-Gauss-Bonnet theories
during the reheating and the end of inflationary era. Given the scalar field
potential $V(\phi)$ which can have some intrinsic importance for the theory,
determining the scalar coupling function $\xi(\phi)$ can be cumbersome due to
lack of analyticity. The GW170817 observation constrains the scalar coupling
function and the scalar field potential to have some interdependence, thus
during the slow-roll era one can calculate the scalar coupling function.
However, when the slow-roll era ends, it is expected that the scalar coupling
function should have a different form and the same applies for the reheating
era, assuming that the scalar potential of the theory does not change. In this
work we exactly aim to highlight this feature of Einstein-Gauss-Bonnet
theories, as the Universe evolves through distinct sequential evolution eras,
and we focus on how to determine the scalar coupling function during the
various evolutionary eras, from inflation to the reheating era. Regarding both
the end of the inflationary era and the reheating era, it is found that the
Hubble rate obeys a constant-roll-like condition of the form $\dot{H}=\delta
H^2$, thus the determination of the scalar Gauss-Bonnet function $\xi(\phi)$ is
reduced to solving a differential equation. A mentionable feature of the era
exactly at the end of inflation is that the Klein-Gordon equation is decoupled
from the field equations, because the Gauss-Bonnet invariant is zero. We
provide several examples of interest to support our arguments.
| [
{
"created": "Sat, 20 Jan 2024 17:03:04 GMT",
"version": "v1"
}
] | 2024-01-23 | [
[
"Oikonomou",
"V. K.",
""
],
[
"Tsyba",
"Pyotr",
""
],
[
"Razina",
"Olga",
""
]
] | In this work we study the GW170817-compatible Einstein-Gauss-Bonnet theories during the reheating and the end of inflationary era. Given the scalar field potential $V(\phi)$ which can have some intrinsic importance for the theory, determining the scalar coupling function $\xi(\phi)$ can be cumbersome due to lack of analyticity. The GW170817 observation constrains the scalar coupling function and the scalar field potential to have some interdependence, thus during the slow-roll era one can calculate the scalar coupling function. However, when the slow-roll era ends, it is expected that the scalar coupling function should have a different form and the same applies for the reheating era, assuming that the scalar potential of the theory does not change. In this work we exactly aim to highlight this feature of Einstein-Gauss-Bonnet theories, as the Universe evolves through distinct sequential evolution eras, and we focus on how to determine the scalar coupling function during the various evolutionary eras, from inflation to the reheating era. Regarding both the end of the inflationary era and the reheating era, it is found that the Hubble rate obeys a constant-roll-like condition of the form $\dot{H}=\delta H^2$, thus the determination of the scalar Gauss-Bonnet function $\xi(\phi)$ is reduced to solving a differential equation. A mentionable feature of the era exactly at the end of inflation is that the Klein-Gordon equation is decoupled from the field equations, because the Gauss-Bonnet invariant is zero. We provide several examples of interest to support our arguments. |
1707.00255 | Thomas Cailleteau Mr | Thomas Cailleteau | Langton's Ant from the Ant's referential | First part of the work | null | null | null | gr-qc nlin.CG | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The evolution of the Langton's ant on a 2D lattice is studied from the "ant's
framework". The aim of this article is twofold. Firstly, to see if one can
explain the emergent behaviour of the ant as an analogous sytem of a particle
crossing an horizon. Secondly, pointing toward some directions for an
explanation, the evolution of the density of one color is studied and
commented.
| [
{
"created": "Sun, 2 Jul 2017 08:18:05 GMT",
"version": "v1"
}
] | 2017-07-04 | [
[
"Cailleteau",
"Thomas",
""
]
] | The evolution of the Langton's ant on a 2D lattice is studied from the "ant's framework". The aim of this article is twofold. Firstly, to see if one can explain the emergent behaviour of the ant as an analogous sytem of a particle crossing an horizon. Secondly, pointing toward some directions for an explanation, the evolution of the density of one color is studied and commented. |
2404.05677 | Bruce Allen | Bruce Allen | Pulsar Timing Array Harmonic Analysis and Source Angular Correlations | Updated with citations to recent work by others; shifted to
covariance C(O.O') to unify notation with [51]. 22 pages, 1 figure | null | null | null | gr-qc astro-ph.CO | http://creativecommons.org/licenses/by/4.0/ | Gravitational waves (GWs) influence the arrival times of radio signals coming
from pulsars. Here, we investigate the harmonic space approach to describing a
pulsar's response to GWs. We derive and discuss the "diagonalized form" of the
response, which is a sum of spin-2-weighted spherical harmonics of the GW
direction multiplied by normal (spin-weight 0) spherical harmonics of the
pulsar direction. We show how this allows many useful objects, for example, the
Hellings and Downs two-point function, to be easily calculated. The approach
also provides a clear description of the gauge dependence. We then employ this
harmonic approach to model the effects of angular correlations in the sky
locations of GW sources (sometimes called "statistical isotropy"). To do this,
we construct rotationally invariant ensembles made up of many Gaussian
subensembles, each of which breaks rotational invariance. Using harmonic
techniques, we compute the cosmic covariance and the total covariance of the
Hellings and Downs correlation in these models. The results may be used to
assess the impact of angular source correlations on the Hellings and Downs
correlation, and for optimal reconstruction of the Hellings and Downs curve in
models where GW sources have correlated sky locations.
| [
{
"created": "Mon, 8 Apr 2024 16:56:45 GMT",
"version": "v1"
},
{
"created": "Mon, 29 Apr 2024 16:42:34 GMT",
"version": "v2"
}
] | 2024-04-30 | [
[
"Allen",
"Bruce",
""
]
] | Gravitational waves (GWs) influence the arrival times of radio signals coming from pulsars. Here, we investigate the harmonic space approach to describing a pulsar's response to GWs. We derive and discuss the "diagonalized form" of the response, which is a sum of spin-2-weighted spherical harmonics of the GW direction multiplied by normal (spin-weight 0) spherical harmonics of the pulsar direction. We show how this allows many useful objects, for example, the Hellings and Downs two-point function, to be easily calculated. The approach also provides a clear description of the gauge dependence. We then employ this harmonic approach to model the effects of angular correlations in the sky locations of GW sources (sometimes called "statistical isotropy"). To do this, we construct rotationally invariant ensembles made up of many Gaussian subensembles, each of which breaks rotational invariance. Using harmonic techniques, we compute the cosmic covariance and the total covariance of the Hellings and Downs correlation in these models. The results may be used to assess the impact of angular source correlations on the Hellings and Downs correlation, and for optimal reconstruction of the Hellings and Downs curve in models where GW sources have correlated sky locations. |
1208.3796 | Stanley P. Gudder | Stanley P Gudder | The Causal Poset is Directed but not Lattice Ordered | The counterexample is incorrect. Thanks to Rafael Sorkin and David
Rideout for pointing this out | null | null | null | gr-qc quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In the causal set approach to discrete quantum gravity the universe grows one
element at a time in discrete steps. At each step the process has the form of a
causal set (causet) and the "completed" universe is given by a path through a
discretely growing chain of causets. The collection of causets forms a
partially ordered set (poset) in a natural way. We first show that this poset
is directed. We then give a counterexample which shows it is not lattice
ordered.
| [
{
"created": "Sun, 19 Aug 2012 01:10:24 GMT",
"version": "v1"
},
{
"created": "Sat, 28 Sep 2013 18:49:40 GMT",
"version": "v2"
}
] | 2013-10-01 | [
[
"Gudder",
"Stanley P",
""
]
] | In the causal set approach to discrete quantum gravity the universe grows one element at a time in discrete steps. At each step the process has the form of a causal set (causet) and the "completed" universe is given by a path through a discretely growing chain of causets. The collection of causets forms a partially ordered set (poset) in a natural way. We first show that this poset is directed. We then give a counterexample which shows it is not lattice ordered. |
0811.4129 | Martin Bojowald | Martin Bojowald | Consistent Loop Quantum Cosmology | 13 pages | Class.Quant.Grav.26:075020,2009 | 10.1088/0264-9381/26/7/075020 | IGC-08/11-5 | gr-qc astro-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A consistent combination of quantum geometry effects rules out a large class
of models of loop quantum cosmology and their critical densities as they have
been used in the recent literature. In particular, the critical density at
which an isotropic universe filled with a free, massless scalar field would
bounce must be well below the Planck density. In the presence of anisotropy, no
model of the Schwarzschild black hole interior analyzed so far is consistent.
| [
{
"created": "Tue, 25 Nov 2008 16:58:46 GMT",
"version": "v1"
}
] | 2009-03-27 | [
[
"Bojowald",
"Martin",
""
]
] | A consistent combination of quantum geometry effects rules out a large class of models of loop quantum cosmology and their critical densities as they have been used in the recent literature. In particular, the critical density at which an isotropic universe filled with a free, massless scalar field would bounce must be well below the Planck density. In the presence of anisotropy, no model of the Schwarzschild black hole interior analyzed so far is consistent. |
0709.3302 | Salvador Robles-Perez | S. Robles-Perez, Y. Hassouni and P. F. Gonzalez-Diaz | Coherent states in quantum cosmology | 6 pages, 2 figures | null | null | null | gr-qc | null | In the realm of a quantum cosmological model for dark energy in which we have
been able to construct a well-defined Hilbert space, a consistent coherent
state representation has been formulated that may describe the quantum state of
the universe and has a well-behaved semiclassical limit.
| [
{
"created": "Thu, 20 Sep 2007 20:16:17 GMT",
"version": "v1"
}
] | 2007-09-24 | [
[
"Robles-Perez",
"S.",
""
],
[
"Hassouni",
"Y.",
""
],
[
"Gonzalez-Diaz",
"P. F.",
""
]
] | In the realm of a quantum cosmological model for dark energy in which we have been able to construct a well-defined Hilbert space, a consistent coherent state representation has been formulated that may describe the quantum state of the universe and has a well-behaved semiclassical limit. |
gr-qc/9508027 | Yoav Peleg | Sukanta Bose, Leonard Parker and Yoav Peleg (UWM) | Hawking Radiation and Unitary evolution | LaTex file + uuencoded ps version including 4 figures | Phys.Rev.Lett. 76 (1996) 861-864 | 10.1103/PhysRevLett.76.861 | WISC-MILW-95-TH-17 | gr-qc hep-th | null | We find a family of exact solutions to the semi-classical equations
(including back-reaction) of two-dimensional dilaton gravity, describing
infalling null matter that becomes outgoing and returns to infinity without
forming a black hole. When a black hole almost forms, the radiation reaching
infinity in advance of the original outgoing null matter has the properties of
Hawking radiation. The radiation reaching infinity after the null matter
consists of a brief burst of negative energy that preserves unitarity and
transfers information faster than the theoretical bound for positive energy.
| [
{
"created": "Thu, 10 Aug 1995 21:55:43 GMT",
"version": "v1"
},
{
"created": "Fri, 11 Aug 1995 16:10:39 GMT",
"version": "v2"
}
] | 2009-10-28 | [
[
"Bose",
"Sukanta",
"",
"UWM"
],
[
"Parker",
"Leonard",
"",
"UWM"
],
[
"Peleg",
"Yoav",
"",
"UWM"
]
] | We find a family of exact solutions to the semi-classical equations (including back-reaction) of two-dimensional dilaton gravity, describing infalling null matter that becomes outgoing and returns to infinity without forming a black hole. When a black hole almost forms, the radiation reaching infinity in advance of the original outgoing null matter has the properties of Hawking radiation. The radiation reaching infinity after the null matter consists of a brief burst of negative energy that preserves unitarity and transfers information faster than the theoretical bound for positive energy. |
2105.10178 | Pedro Bargue\~no | Pedro Bargueno, Ernesto Contreras and Angel Rincon | Thermodynamics of scale-dependent Friedmann equations | To be published in EPJC | null | 10.1140/epjc/s10052-021-09274-7 | null | gr-qc | http://creativecommons.org/licenses/by/4.0/ | In this work, the role of a time-varying Newton constant under the
scale-dependent approach is investigated in the thermodynamics of the Friedman
equations. In particular, we show that the extended Friedman equations can be
derived either from equilibrium thermodynamics when the non-matter energy
momentum tensor is interpreted as a fluid or from non-equilibrium
thermodynamics when an entropy production term, which depends on the
time-varying Newton constant, is included. Finally, a comparison between black
hole and cosmological thermodynamics in the framework of scale--dependent
gravity is briefly discussed.
| [
{
"created": "Fri, 21 May 2021 07:37:53 GMT",
"version": "v1"
}
] | 2021-06-16 | [
[
"Bargueno",
"Pedro",
""
],
[
"Contreras",
"Ernesto",
""
],
[
"Rincon",
"Angel",
""
]
] | In this work, the role of a time-varying Newton constant under the scale-dependent approach is investigated in the thermodynamics of the Friedman equations. In particular, we show that the extended Friedman equations can be derived either from equilibrium thermodynamics when the non-matter energy momentum tensor is interpreted as a fluid or from non-equilibrium thermodynamics when an entropy production term, which depends on the time-varying Newton constant, is included. Finally, a comparison between black hole and cosmological thermodynamics in the framework of scale--dependent gravity is briefly discussed. |
2207.14652 | Mikhail Altaisky | Mikhail Altaisky and Robin Raj | Can our spacetime emerge from anti -- de Sitter space? | LaTeX, 4 pages, 2 eps figures | Physics of Particles and Nuclei Letters, 2022, vol.19, No 4,
pp.313-316 | 10.1134/S1547477122040033 | null | gr-qc hep-th | http://creativecommons.org/licenses/by/4.0/ | We present a model showing that our four-dimensional spacetime with the
signature $(+,-,-,-)$ and almost vanishing positive curvature may have
originated from a $b$-ary tree-like branching of a single discrete entity, and
the $AdS_5$ space related to this branching process.
| [
{
"created": "Wed, 27 Jul 2022 05:23:35 GMT",
"version": "v1"
}
] | 2022-08-01 | [
[
"Altaisky",
"Mikhail",
""
],
[
"Raj",
"Robin",
""
]
] | We present a model showing that our four-dimensional spacetime with the signature $(+,-,-,-)$ and almost vanishing positive curvature may have originated from a $b$-ary tree-like branching of a single discrete entity, and the $AdS_5$ space related to this branching process. |
0801.4584 | Abel Camacho Mr. | Alfredo Macias, Abel Camacho, Jutta Kunz, Claus Laemmerzahl | Midisuperspace Supersymmetric Quantum Cosmology | Accepted in Physical Review D | Phys.Rev.D77:064009,2008 | 10.1103/PhysRevD.77.064009 | null | gr-qc | null | We investigate the canonical quantization in the framework of N=1 simple
supergravity for the case of a very simple gravitational midisuperspace
described by Gowdy $T^3$ cosmological models. We consider supersymmetric
quantum cosmology in the mentioned midisuperspace, where a matrix
representation for the gravitino covector--spinor is used. The full Lorentz
constraint and its implications for the wave function of the universe are
analyzed in detail. We found that there are indeed physical states in the
midisuperspace sector of the theory in contrast to the case of minisuperspace
where there exist no physical states.
| [
{
"created": "Tue, 29 Jan 2008 23:58:42 GMT",
"version": "v1"
}
] | 2008-11-26 | [
[
"Macias",
"Alfredo",
""
],
[
"Camacho",
"Abel",
""
],
[
"Kunz",
"Jutta",
""
],
[
"Laemmerzahl",
"Claus",
""
]
] | We investigate the canonical quantization in the framework of N=1 simple supergravity for the case of a very simple gravitational midisuperspace described by Gowdy $T^3$ cosmological models. We consider supersymmetric quantum cosmology in the mentioned midisuperspace, where a matrix representation for the gravitino covector--spinor is used. The full Lorentz constraint and its implications for the wave function of the universe are analyzed in detail. We found that there are indeed physical states in the midisuperspace sector of the theory in contrast to the case of minisuperspace where there exist no physical states. |
gr-qc/0611022 | Kirill Bronnikov | K.A. Bronnikov, H. Dehnen, V.N. Melnikov | Regular black holes and black universes | 13 pages, 1 figure. 6 referenses and some discussion added, misprints
corrected | Gen.Rel.Grav.39:973-987,2007 | 10.1007/s10714-007-0430-6 | null | gr-qc | null | We give a comparative description of different types of regular static,
spherically symmetric black holes (BHs) and discuss in more detail their
particular type, which we suggest to call black universes. The latter have a
Schwarzschild-like causal structure, but inside the horizon there is an
expanding Kantowski-Sachs universe and a de Sitter infinity instead of a
singularity. Thus a hypothetic BH explorer gets a chance to survive. Solutions
of this kind are naturally obtained if one considers static, spherically
symmetric distributions of various (but not all) kinds of phantom matter whose
existence is favoured by cosmological observations. It also looks possible that
our Universe has originated from phantom-dominated collapse in another universe
and underwent isotropization after crossing the horizon. An explicit example of
a black-universe solution with positive Schwarzschild mass is discussed.
| [
{
"created": "Fri, 3 Nov 2006 15:28:27 GMT",
"version": "v1"
},
{
"created": "Sun, 12 Nov 2006 18:08:31 GMT",
"version": "v2"
}
] | 2008-11-26 | [
[
"Bronnikov",
"K. A.",
""
],
[
"Dehnen",
"H.",
""
],
[
"Melnikov",
"V. N.",
""
]
] | We give a comparative description of different types of regular static, spherically symmetric black holes (BHs) and discuss in more detail their particular type, which we suggest to call black universes. The latter have a Schwarzschild-like causal structure, but inside the horizon there is an expanding Kantowski-Sachs universe and a de Sitter infinity instead of a singularity. Thus a hypothetic BH explorer gets a chance to survive. Solutions of this kind are naturally obtained if one considers static, spherically symmetric distributions of various (but not all) kinds of phantom matter whose existence is favoured by cosmological observations. It also looks possible that our Universe has originated from phantom-dominated collapse in another universe and underwent isotropization after crossing the horizon. An explicit example of a black-universe solution with positive Schwarzschild mass is discussed. |
2103.10555 | Jens Boos | Jens Boos, Ivan Kol\'a\v{r} | Non-locality and gravitoelectromagnetic duality | 8 pages, comments welcome! | Phys. Rev. D 104, 024018 (2021) | 10.1103/PhysRevD.104.024018 | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The weak-field Schwarzschild and NUT solutions of general relativity are
gravitoelectromagnetically dual to each other, except on the positive $z$-axis.
The presence of non-locality weakens this duality and violates it within a
smeared region around the positive $z$-axis, whose typical transverse size is
given by the scale of non-locality. We restore an exact non-local
gravitoelectromagnetic duality everywhere via a manifestly dual modification of
the linearized non-local field equations. In the limit of vanishing
non-locality we recover the well-known results from weak-field general
relativity.
| [
{
"created": "Thu, 18 Mar 2021 22:51:38 GMT",
"version": "v1"
}
] | 2021-07-14 | [
[
"Boos",
"Jens",
""
],
[
"Kolář",
"Ivan",
""
]
] | The weak-field Schwarzschild and NUT solutions of general relativity are gravitoelectromagnetically dual to each other, except on the positive $z$-axis. The presence of non-locality weakens this duality and violates it within a smeared region around the positive $z$-axis, whose typical transverse size is given by the scale of non-locality. We restore an exact non-local gravitoelectromagnetic duality everywhere via a manifestly dual modification of the linearized non-local field equations. In the limit of vanishing non-locality we recover the well-known results from weak-field general relativity. |
gr-qc/9705085 | Alexander L. Gromov | Vladik Kreinovich and R. R. Zapatrin | An operationalistic reformulation of Einstein's equivalence principle | latex | null | null | IRB-MSP-970530 | gr-qc | null | The Einstein's equivalence principle is formulated in terms of the accuracy
of measurements and its dependence of the size of the area of measurement. It
is shown that different refinements of the statement 'the spacetime is locally
flat' lead to different conculsions about the spacetime geometry.
| [
{
"created": "Fri, 30 May 1997 20:30:18 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Kreinovich",
"Vladik",
""
],
[
"Zapatrin",
"R. R.",
""
]
] | The Einstein's equivalence principle is formulated in terms of the accuracy of measurements and its dependence of the size of the area of measurement. It is shown that different refinements of the statement 'the spacetime is locally flat' lead to different conculsions about the spacetime geometry. |
1604.00075 | Jonah Miller | Jonah M. Miller and Erik Schnetter | An Operator-Based Local Discontinuous Galerkin Method Compatible With
the BSSN Formulation of the Einstein Equations | Incorporated referee comments during peer-review. Added several
references pointed out to us. Added a figure and discussion comparing
pointwise error for 4th- and 5th-order stencils for wave equation | Class. Quantum Grav. 34 (2017) 1 | 10.1088/1361-6382/34/1/015003 | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Discontinuous Galerkin Finite Element (DGFE) methods offer a mathematically
beautiful, computationally efficient, and efficiently parallelizable way to
solve hyperbolic partial differential equations. These properties make them
highly desirable for numerical calculations in relativistic astrophysics and
many other fields. The BSSN formulation of the Einstein equations has
repeatedly demonstrated its robustness. The formulation is not only stable but
allows for puncture-type evolutions of black hole systems. To-date no one has
been able to solve the full (3+1)-dimensional BSSN equations using DGFE
methods. This is partly because DGFE discretization often occurs at the level
of the equations, not the derivative operator, and partly because DGFE methods
are traditionally formulated for manifestly flux-conservative systems. By
discretizing the derivative operator, we generalize a particular flavor of DGFE
methods, Local DG methods, to solve arbitrary second-order hyperbolic
equations. Because we discretize at the level of the derivative operator, our
method can be interpreted as either a DGFE method or as a finite differences
stencil with non-constant coefficients.
| [
{
"created": "Thu, 31 Mar 2016 23:06:49 GMT",
"version": "v1"
},
{
"created": "Thu, 14 Apr 2016 16:24:58 GMT",
"version": "v2"
},
{
"created": "Mon, 14 Nov 2016 23:00:37 GMT",
"version": "v3"
}
] | 2016-12-12 | [
[
"Miller",
"Jonah M.",
""
],
[
"Schnetter",
"Erik",
""
]
] | Discontinuous Galerkin Finite Element (DGFE) methods offer a mathematically beautiful, computationally efficient, and efficiently parallelizable way to solve hyperbolic partial differential equations. These properties make them highly desirable for numerical calculations in relativistic astrophysics and many other fields. The BSSN formulation of the Einstein equations has repeatedly demonstrated its robustness. The formulation is not only stable but allows for puncture-type evolutions of black hole systems. To-date no one has been able to solve the full (3+1)-dimensional BSSN equations using DGFE methods. This is partly because DGFE discretization often occurs at the level of the equations, not the derivative operator, and partly because DGFE methods are traditionally formulated for manifestly flux-conservative systems. By discretizing the derivative operator, we generalize a particular flavor of DGFE methods, Local DG methods, to solve arbitrary second-order hyperbolic equations. Because we discretize at the level of the derivative operator, our method can be interpreted as either a DGFE method or as a finite differences stencil with non-constant coefficients. |
0710.5656 | Sergey Sushkov | P.E. Kashargin and S.V. Sushkov | Slowly rotating wormholes: the first order approximation | 7 pages, 2 figures, submitted to Gravitation and Cosmology | Grav.Cosmol.14:80-85,2008 | 10.1007/s12267-008-1010-y | null | gr-qc | null | We discuss a solution describing a rotating wormhole in the theory of gravity
with a scalar field with negative kinetic energy. To solve the problem we use
the assumption about slow rotation. The role of a small dimensionless parameter
plays the ratio of the linear velocity of rotation of the wormhole's throat and
the velocity of light. The rotating wormhole solution is constructed in the
framework of the first order approximation with respect to the small parameter.
We analyze the obtained solution and study the motion of test particles and the
propagation of light in the spacetime of rotating wormhole.
| [
{
"created": "Tue, 30 Oct 2007 14:26:53 GMT",
"version": "v1"
}
] | 2009-11-13 | [
[
"Kashargin",
"P. E.",
""
],
[
"Sushkov",
"S. V.",
""
]
] | We discuss a solution describing a rotating wormhole in the theory of gravity with a scalar field with negative kinetic energy. To solve the problem we use the assumption about slow rotation. The role of a small dimensionless parameter plays the ratio of the linear velocity of rotation of the wormhole's throat and the velocity of light. The rotating wormhole solution is constructed in the framework of the first order approximation with respect to the small parameter. We analyze the obtained solution and study the motion of test particles and the propagation of light in the spacetime of rotating wormhole. |
2111.05732 | Javier Bad\'ia | Javier Bad\'ia, Ernesto F. Eiroa | Shadow of a charged black hole surrounded by an anisotropic matter field | 8 pages, 5 figures; prepared for the Proceedings of the Sixteenth
Marcel Grossmann Meeting - MG16 | Proceedings of the Sixteenth Marcel Grossmann Meeting (MG16),
pages 1343-1350 (World Scientific, Singapore, 2023) | 10.1142/9789811269776_0108 | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A certain type of matter with anisotropic pressures can add to the
Reissner-Nordstr\"om metric a term proportional to a power of the radial
coordinate. Using the standard method of separating variables for the
Hamilton-Jacobi equation, we study the shadow of the corresponding rotating
solution, obtained through the Newman-Janis algorithm. We define and calculate
three observables in order to characterize the position, size and shape of the
shadow.
| [
{
"created": "Wed, 10 Nov 2021 15:13:43 GMT",
"version": "v1"
}
] | 2023-01-30 | [
[
"Badía",
"Javier",
""
],
[
"Eiroa",
"Ernesto F.",
""
]
] | A certain type of matter with anisotropic pressures can add to the Reissner-Nordstr\"om metric a term proportional to a power of the radial coordinate. Using the standard method of separating variables for the Hamilton-Jacobi equation, we study the shadow of the corresponding rotating solution, obtained through the Newman-Janis algorithm. We define and calculate three observables in order to characterize the position, size and shape of the shadow. |
gr-qc/0201087 | Sergey Alexandrov | Sergei Alexandrov | Hilbert space structure of covariant loop quantum gravity | 20 pages, RevTEX | Phys.Rev. D66 (2002) 024028 | 10.1103/PhysRevD.66.024028 | null | gr-qc | null | We investigate the Hilbert space in the Lorentz covariant approach to loop
quantum gravity. We restrict ourselves to the space where all area operators
are simultaneously diagonalizable, assuming that it exists. In this sector
quantum states are realized by a generalization of spin network states based on
Lorentz Wilson lines projected on irreducible representations of an SO(3)
subgroup. The problem of infinite dimensionality of the unitary Lorentz
representations is absent due to this projection. Nevertheless, the projection
preserves the Lorentz covariance of the Wilson lines so that the symmetry is
not broken. Under certain conditions the states can be thought as functions on
a homogeneous space. We define the inner product as an integral over this
space. With respect to this inner product the spin networks form an orthonormal
basis in the investigated sector. We argue that it is the only relevant part of
a larger state space arising in the approach. The problem of the
noncommutativity of the Lorentz connection is solved by restriction to the
simple representations. The resulting structure shows similarities with the
spin foam approach.
| [
{
"created": "Mon, 28 Jan 2002 21:33:37 GMT",
"version": "v1"
}
] | 2009-11-07 | [
[
"Alexandrov",
"Sergei",
""
]
] | We investigate the Hilbert space in the Lorentz covariant approach to loop quantum gravity. We restrict ourselves to the space where all area operators are simultaneously diagonalizable, assuming that it exists. In this sector quantum states are realized by a generalization of spin network states based on Lorentz Wilson lines projected on irreducible representations of an SO(3) subgroup. The problem of infinite dimensionality of the unitary Lorentz representations is absent due to this projection. Nevertheless, the projection preserves the Lorentz covariance of the Wilson lines so that the symmetry is not broken. Under certain conditions the states can be thought as functions on a homogeneous space. We define the inner product as an integral over this space. With respect to this inner product the spin networks form an orthonormal basis in the investigated sector. We argue that it is the only relevant part of a larger state space arising in the approach. The problem of the noncommutativity of the Lorentz connection is solved by restriction to the simple representations. The resulting structure shows similarities with the spin foam approach. |
2105.13260 | Marcus Khuri | Marcus Khuri, Gilbert Weinstein, Sumio Yamada | Balancing Static Vacuum Black Holes with Signed Masses in 4 and 5
Dimensions | 35 pages, 7 figures | Phys. Rev. D 104, 044063 (2021) | 10.1103/PhysRevD.104.044063 | null | gr-qc hep-th math.DG | http://creativecommons.org/licenses/by/4.0/ | We construct a new set of asymptotically flat, static vacuum solutions to the
Einstein equations in dimensions 4 and 5, which may be interpreted as a
superposition of positive and negative mass black holes. The resulting
spacetimes are axisymmetric in 4-dimensions and bi-axisymmetric in
5-dimensions, and are regular away from the negative mass singularities, for
instance conical singularities are absent along the axes. In 5-dimensions, the
topologies of signed mass black holes used in the construction may be either
spheres $S^3$ or rings $S^1 \times S^2$; in particular, the negative mass
static black ring solution is introduced. A primary observation that
facilitates the superposition is the fact that, in Weyl-Papapetrou coordinates,
negative mass singularities arise as overlapping singular support for a
particular type of Green's function. Furthermore, a careful analysis of conical
singularities along axes is performed, and formulas are obtained for their
propagation across horizons, negative mass singularities, and corners. The
methods are robust, and may be used to construct a multitude of further
examples. Lastly, we show that balancing does not occur between any two signed
mass black holes of the type studied here in 4 dimensions, while in 5
dimensions two-body balancing is possible.
| [
{
"created": "Thu, 27 May 2021 15:56:54 GMT",
"version": "v1"
},
{
"created": "Thu, 26 Aug 2021 19:22:05 GMT",
"version": "v2"
}
] | 2021-09-01 | [
[
"Khuri",
"Marcus",
""
],
[
"Weinstein",
"Gilbert",
""
],
[
"Yamada",
"Sumio",
""
]
] | We construct a new set of asymptotically flat, static vacuum solutions to the Einstein equations in dimensions 4 and 5, which may be interpreted as a superposition of positive and negative mass black holes. The resulting spacetimes are axisymmetric in 4-dimensions and bi-axisymmetric in 5-dimensions, and are regular away from the negative mass singularities, for instance conical singularities are absent along the axes. In 5-dimensions, the topologies of signed mass black holes used in the construction may be either spheres $S^3$ or rings $S^1 \times S^2$; in particular, the negative mass static black ring solution is introduced. A primary observation that facilitates the superposition is the fact that, in Weyl-Papapetrou coordinates, negative mass singularities arise as overlapping singular support for a particular type of Green's function. Furthermore, a careful analysis of conical singularities along axes is performed, and formulas are obtained for their propagation across horizons, negative mass singularities, and corners. The methods are robust, and may be used to construct a multitude of further examples. Lastly, we show that balancing does not occur between any two signed mass black holes of the type studied here in 4 dimensions, while in 5 dimensions two-body balancing is possible. |
gr-qc/9804056 | George Lavrelashvili | George Lavrelashvili | On the quadratic action of the Hawking-Turok instanton | 8 pages, REVTeX, 4 eps figures (included); statement concerning the
CD solution is corrected and few other minor changes are made | Phys. Rev. D 58, 063505 (1998) | 10.1103/PhysRevD.58.063505 | BUTP-98/12 | gr-qc hep-th | null | Positive definiteness of the quadratic part of the action of the
Hawking-Turok instanton is investigated. The Euclidean quadratic action for
scalar perturbations is expressed in terms of a single gauge invariant quantity
$q$. The mode functions satisfy a Schr\"odinger type equation with a potential
$U$. It is shown that the potential $U$ tends to a positive constant at the
regular end of the instanton. The detailed shape of $U$ depends on the initial
data of the instanton, on parameters of the background scalar field potential
$V$ and on a positive integer, $p$, labeling different spherical harmonics. For
certain well behaved scalar field potentials it is proven analytically that for
$p>1$ quadratic action is non-negative. For the lowest $p=1$ (homogeneous)
harmonic numerical solution of the Schr\"odinger equation for different scalar
field potentials $V$ and different initial data show that in some cases the
potential $U$ is negative in the intermediate region. We investigated the
monotonously growing potentials and a potential with a false vacuum. For the
monotonous potentials no negative modes are found about the Hawking-Turok
instanton. For a potential with the false vacuum the HT instanton is shown to
have a negative mode for certain initial data.
| [
{
"created": "Wed, 22 Apr 1998 18:12:39 GMT",
"version": "v1"
},
{
"created": "Fri, 1 May 1998 21:32:00 GMT",
"version": "v2"
}
] | 2016-08-25 | [
[
"Lavrelashvili",
"George",
""
]
] | Positive definiteness of the quadratic part of the action of the Hawking-Turok instanton is investigated. The Euclidean quadratic action for scalar perturbations is expressed in terms of a single gauge invariant quantity $q$. The mode functions satisfy a Schr\"odinger type equation with a potential $U$. It is shown that the potential $U$ tends to a positive constant at the regular end of the instanton. The detailed shape of $U$ depends on the initial data of the instanton, on parameters of the background scalar field potential $V$ and on a positive integer, $p$, labeling different spherical harmonics. For certain well behaved scalar field potentials it is proven analytically that for $p>1$ quadratic action is non-negative. For the lowest $p=1$ (homogeneous) harmonic numerical solution of the Schr\"odinger equation for different scalar field potentials $V$ and different initial data show that in some cases the potential $U$ is negative in the intermediate region. We investigated the monotonously growing potentials and a potential with a false vacuum. For the monotonous potentials no negative modes are found about the Hawking-Turok instanton. For a potential with the false vacuum the HT instanton is shown to have a negative mode for certain initial data. |
2106.10425 | Pramit Rej | Piyali Bhar, Pramit Rej, P. Mafa Takisa, and M. Zubair | Relativistic compact stars in Tolman spacetime via an anisotropic
approach | 18 Pages, 8 Figures, Accepted in European Physical Journal C on
12.06.2021 | The European Physical Journal C 81, 531 (2021) | 10.1140/epjc/s10052-021-09340-0 | null | gr-qc astro-ph.GA | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this present work, we have obtained a singularity-free spherically
symmetric stellar model with anisotropic pressure in the background of
Einstein's general theory of relativity. The Einstein's field equations have
been solved by exploiting Tolman {\em ansatz} [Richard C Tolman, Phys. Rev.
55:364, 1939] in $(3+1)$-dimensional space-time. Using observed values of mass
and radius of the compact star PSR J1903+327, we have calculated the numerical
values of all the constants from the boundary conditions. All the physical
characteristics of the proposed model have been discussed both analytically and
graphically. The new exact solution satisfies all the physical criteria for a
realistic compact star. The matter variables are regular and well behaved
throughout the stellar structure. Constraints on model parameters have been
obtained. All the energy conditions are verified with the help of graphical
representation. The stability condition of the present model has been described
through different testings.
| [
{
"created": "Sat, 19 Jun 2021 05:22:30 GMT",
"version": "v1"
}
] | 2021-06-23 | [
[
"Bhar",
"Piyali",
""
],
[
"Rej",
"Pramit",
""
],
[
"Takisa",
"P. Mafa",
""
],
[
"Zubair",
"M.",
""
]
] | In this present work, we have obtained a singularity-free spherically symmetric stellar model with anisotropic pressure in the background of Einstein's general theory of relativity. The Einstein's field equations have been solved by exploiting Tolman {\em ansatz} [Richard C Tolman, Phys. Rev. 55:364, 1939] in $(3+1)$-dimensional space-time. Using observed values of mass and radius of the compact star PSR J1903+327, we have calculated the numerical values of all the constants from the boundary conditions. All the physical characteristics of the proposed model have been discussed both analytically and graphically. The new exact solution satisfies all the physical criteria for a realistic compact star. The matter variables are regular and well behaved throughout the stellar structure. Constraints on model parameters have been obtained. All the energy conditions are verified with the help of graphical representation. The stability condition of the present model has been described through different testings. |
1502.04640 | Jonathan Engle | Jonathan Engle and Antonia Zipfel | The Lorentzian proper vertex amplitude: Classical analysis and quantum
derivation | 36 pages; references corrected | Phys. Rev. D 94, 064024 (2016) | 10.1103/PhysRevD.94.064024 | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Spin foam models, an approach to defining the dynamics of loop quantum
gravity, make use of the Plebanski formulation of gravity, in which gravity is
recovered from a topological field theory via certain constraints called
simplicity constraints. However, the simplicity constraints in their usual form
select more than just one gravitational sector as well as a degenerate sector.
This was shown, in previous work, to be the reason for the "extra" terms
appearing in the semiclassical limit of the Euclidean EPRL amplitude. In this
previous work, a way to eliminate the extra sectors, and hence terms, was
developed, leading to the what was called the Euclidean proper vertex
amplitude. In the present work, these results are extended to the Lorentzian
signature, establishing what is called the Lorentzian proper vertex amplitude.
This extension is non-trivial and involves a number of new elements since, for
Lorentzian bivectors, the split into self-dual and anti-self-dual parts, on
which the Euclidean derivation was based, is no longer available. In fact, the
classical parts of the present derivation provide not only an extension to the
Lorentzian case, but also, with minor modifications, provide a new, more four
dimensionally covariant derivation for the Euclidean case. The new elements in
the quantum part of the derivation are due to the different structure of
unitary representations of the Lorentz group.
| [
{
"created": "Mon, 16 Feb 2015 17:28:27 GMT",
"version": "v1"
},
{
"created": "Tue, 31 May 2016 12:20:16 GMT",
"version": "v2"
}
] | 2016-09-14 | [
[
"Engle",
"Jonathan",
""
],
[
"Zipfel",
"Antonia",
""
]
] | Spin foam models, an approach to defining the dynamics of loop quantum gravity, make use of the Plebanski formulation of gravity, in which gravity is recovered from a topological field theory via certain constraints called simplicity constraints. However, the simplicity constraints in their usual form select more than just one gravitational sector as well as a degenerate sector. This was shown, in previous work, to be the reason for the "extra" terms appearing in the semiclassical limit of the Euclidean EPRL amplitude. In this previous work, a way to eliminate the extra sectors, and hence terms, was developed, leading to the what was called the Euclidean proper vertex amplitude. In the present work, these results are extended to the Lorentzian signature, establishing what is called the Lorentzian proper vertex amplitude. This extension is non-trivial and involves a number of new elements since, for Lorentzian bivectors, the split into self-dual and anti-self-dual parts, on which the Euclidean derivation was based, is no longer available. In fact, the classical parts of the present derivation provide not only an extension to the Lorentzian case, but also, with minor modifications, provide a new, more four dimensionally covariant derivation for the Euclidean case. The new elements in the quantum part of the derivation are due to the different structure of unitary representations of the Lorentz group. |
1206.5413 | Jose Socorro Garcia | Juan M. Ram\'irez and J. Socorro | FRW in cosmological self-creation theory | 10 pages in latex, 4 figures | acepted in Int. J. of Theor. Phys. (2013) | 10.1007/s10773-013-1580-9 | null | gr-qc hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We use the Brans-Dicke theory from the framework of General Relativity
(Einstein frame), but now the total energy momentum tensor fulfills the
following condition $\rm <[\{1}{\phi}T^{\mu \nu M}+T^{\mu
\nu}(\phi)>]_{;\nu}=0$. We take as a first model the flat FRW metric and with
the law of variation for Hubble's parameter proposal by Berman \cite{Berman},
we find solutions to the Einstein field equations by the cases: inflation
($\gamma=-1$), radiation ($\gamma=\{1}{3}$), stiff matter ($\gamma=1$). For the
Inflation case the scalar field grows fast and depends strongly of the constant
$\rm M_{\gamma=-1}$ that appears in the solution, for the Radiation case, the
scalar stop its expansion and then decrease perhaps due to the presence of the
first particles. In the Stiff Matter case, the scalar field is decreasing so
for a large time, $\phi\rightarrow0$. In the same line of classical solutions,
we find an exact solution to the Einstein field equations for the stiff matter
$(\gamma=1)$ and flat universe, using the Hamilton-Jacobi scheme.
| [
{
"created": "Sat, 23 Jun 2012 17:02:10 GMT",
"version": "v1"
},
{
"created": "Tue, 7 May 2013 20:45:16 GMT",
"version": "v2"
}
] | 2013-05-09 | [
[
"Ramírez",
"Juan M.",
""
],
[
"Socorro",
"J.",
""
]
] | We use the Brans-Dicke theory from the framework of General Relativity (Einstein frame), but now the total energy momentum tensor fulfills the following condition $\rm <[\{1}{\phi}T^{\mu \nu M}+T^{\mu \nu}(\phi)>]_{;\nu}=0$. We take as a first model the flat FRW metric and with the law of variation for Hubble's parameter proposal by Berman \cite{Berman}, we find solutions to the Einstein field equations by the cases: inflation ($\gamma=-1$), radiation ($\gamma=\{1}{3}$), stiff matter ($\gamma=1$). For the Inflation case the scalar field grows fast and depends strongly of the constant $\rm M_{\gamma=-1}$ that appears in the solution, for the Radiation case, the scalar stop its expansion and then decrease perhaps due to the presence of the first particles. In the Stiff Matter case, the scalar field is decreasing so for a large time, $\phi\rightarrow0$. In the same line of classical solutions, we find an exact solution to the Einstein field equations for the stiff matter $(\gamma=1)$ and flat universe, using the Hamilton-Jacobi scheme. |
2005.01784 | Olesya Galkina | Olesya Galkina, Alexander Yu. Kamenshchik | Future soft singularities, Born-Infeld-like fields and particles | 13 pages, 1 figure. Final version to be published in PRD | Phys. Rev. D 102, 024078 (2020) | 10.1103/PhysRevD.102.024078 | null | gr-qc hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider different scenarios of the evolution of the universe, where the
singularities or some non-analyticities in the geometry of the spacetime are
present, trying to answer the following question: is it possible to conserve
some kind of notion of particle corresponding to a chosen quantum field present
in the universe when the latter approaches the singularity? We study scalar
fields with different types of Lagrangians, writing down the second-order
differential equations for the linear perturbations of these fields in the
vicinity of a singularity. If both independent solutions are regular, we
construct the vacuum state for quantum particles as a Gaussian function of the
corresponding variable. If at least one of two independent solutions has a
singular asymptotic behavior, then we cannot define the creation and the
annihilation operators and construct the vacuum. This means that the very
notion of particle loses sense. We show that at the approaching to the Big Rip
singularity, particles corresponding to the phantom scalar field driving the
evolution of the universe must vanish, while particles of other fields still
can be defined. In the case of the model of the universe described by the
tachyon field with a special trigonometric potential, where the Big Brake
singularity occurs, we see that the (pseudo) tachyon particles do not pass
through this singularity. Adding to this model some quantity of dust, we
slightly change the characteristics of this singularity and tachyon particles
survive. Finally, we consider a model with the scalar field with the cusped
potential, where the phantom divide line crossing occurs. Here the particles
are well defined in the vicinity of this crossing point.
| [
{
"created": "Mon, 4 May 2020 18:43:35 GMT",
"version": "v1"
},
{
"created": "Tue, 21 Jul 2020 18:45:48 GMT",
"version": "v2"
}
] | 2020-08-05 | [
[
"Galkina",
"Olesya",
""
],
[
"Kamenshchik",
"Alexander Yu.",
""
]
] | We consider different scenarios of the evolution of the universe, where the singularities or some non-analyticities in the geometry of the spacetime are present, trying to answer the following question: is it possible to conserve some kind of notion of particle corresponding to a chosen quantum field present in the universe when the latter approaches the singularity? We study scalar fields with different types of Lagrangians, writing down the second-order differential equations for the linear perturbations of these fields in the vicinity of a singularity. If both independent solutions are regular, we construct the vacuum state for quantum particles as a Gaussian function of the corresponding variable. If at least one of two independent solutions has a singular asymptotic behavior, then we cannot define the creation and the annihilation operators and construct the vacuum. This means that the very notion of particle loses sense. We show that at the approaching to the Big Rip singularity, particles corresponding to the phantom scalar field driving the evolution of the universe must vanish, while particles of other fields still can be defined. In the case of the model of the universe described by the tachyon field with a special trigonometric potential, where the Big Brake singularity occurs, we see that the (pseudo) tachyon particles do not pass through this singularity. Adding to this model some quantity of dust, we slightly change the characteristics of this singularity and tachyon particles survive. Finally, we consider a model with the scalar field with the cusped potential, where the phantom divide line crossing occurs. Here the particles are well defined in the vicinity of this crossing point. |
2311.17993 | Mehrab Momennia | Diego A. Martinez-Valera, Mehrab Momennia, Alfredo Herrera-Aguilar | Observational redshift from general spherically symmetric black holes | 9 pages with 3 captioned figures. Comments are welcome; V2: Published
version | Eur. Phys. J. C 84 (2024) 288 | 10.1140/epjc/s10052-024-12649-1 | null | gr-qc | http://creativecommons.org/licenses/by/4.0/ | In this work, we obtain an expression for the total observational frequency
shift of photons emitted by massive geodesic particles circularly orbiting a
black hole in a general spherically symmetric background. Our general relations
are presented in terms of the metric components and their derivatives that
characterize the black hole parameters. As a concrete example of this general
relativistic approach, a special case is studied by applying the formalism to a
nonsingular black hole conformally related to the Schwarzchild solution that
possesses a length scale parameter $l$ and an integer parameter $N$ in addition
to the black hole mass. Besides, we express the nonsingular black hole mass in
terms of the observational redshift/blueshift. Finally, we investigate the
effects of the free parameters of the conformal gravity theory on the
observational frequency shift and compare results with those of the standard
Schwarzschild black hole.
| [
{
"created": "Wed, 29 Nov 2023 19:00:00 GMT",
"version": "v1"
},
{
"created": "Sun, 24 Mar 2024 22:32:17 GMT",
"version": "v2"
}
] | 2024-03-26 | [
[
"Martinez-Valera",
"Diego A.",
""
],
[
"Momennia",
"Mehrab",
""
],
[
"Herrera-Aguilar",
"Alfredo",
""
]
] | In this work, we obtain an expression for the total observational frequency shift of photons emitted by massive geodesic particles circularly orbiting a black hole in a general spherically symmetric background. Our general relations are presented in terms of the metric components and their derivatives that characterize the black hole parameters. As a concrete example of this general relativistic approach, a special case is studied by applying the formalism to a nonsingular black hole conformally related to the Schwarzchild solution that possesses a length scale parameter $l$ and an integer parameter $N$ in addition to the black hole mass. Besides, we express the nonsingular black hole mass in terms of the observational redshift/blueshift. Finally, we investigate the effects of the free parameters of the conformal gravity theory on the observational frequency shift and compare results with those of the standard Schwarzschild black hole. |
1904.05109 | Kodai Ueda | Vitor Cardoso, Takahisa Igata, Akihiro Ishibashi and Kodai Ueda | Massive tensor field perturbations on extremal and near-extremal static
black holes | no figure, 24 pages | Phys. Rev. D 100, 044013 (2019) | 10.1103/PhysRevD.100.044013 | RUP-19-12 | gr-qc hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We develop a new perturbation method to study the dynamics of massive tensor
fields on extremal and near-extremal static black hole spacetimes in arbitrary
dimensions. On such backgrounds, one can classify the components of massive
tensor fields into the tensor, vector, and scalar-type components. For the
tensor-type components, which arise only in higher dimensions, the massive
tensor field equation reduces to a single master equation, whereas the vector
and scalar-type components remain coupled. We consider the near-horizon
expansion of both the geometry and the field variables with respect to the
near-horizon scaling parameter. By doing so, we reduce, at each order of the
expansion, the equations of motion for the vector and scalar-type components to
a set of five mutually decoupled wave equations with source terms consisting
only of the lower-order variables. Thus, together with the tensor-type master
equation, we obtain the set of mutually decoupled equations at each order of
the expansion that govern all dynamical degrees of freedom of the massive
tensor field on the extremal and near-extremal static black hole background.
| [
{
"created": "Wed, 10 Apr 2019 11:07:39 GMT",
"version": "v1"
}
] | 2019-08-14 | [
[
"Cardoso",
"Vitor",
""
],
[
"Igata",
"Takahisa",
""
],
[
"Ishibashi",
"Akihiro",
""
],
[
"Ueda",
"Kodai",
""
]
] | We develop a new perturbation method to study the dynamics of massive tensor fields on extremal and near-extremal static black hole spacetimes in arbitrary dimensions. On such backgrounds, one can classify the components of massive tensor fields into the tensor, vector, and scalar-type components. For the tensor-type components, which arise only in higher dimensions, the massive tensor field equation reduces to a single master equation, whereas the vector and scalar-type components remain coupled. We consider the near-horizon expansion of both the geometry and the field variables with respect to the near-horizon scaling parameter. By doing so, we reduce, at each order of the expansion, the equations of motion for the vector and scalar-type components to a set of five mutually decoupled wave equations with source terms consisting only of the lower-order variables. Thus, together with the tensor-type master equation, we obtain the set of mutually decoupled equations at each order of the expansion that govern all dynamical degrees of freedom of the massive tensor field on the extremal and near-extremal static black hole background. |
2201.12295 | Jan Sbierski | Jan Sbierski | Instability of the Kerr Cauchy horizon under linearised gravitational
perturbations | 102 pages, 9 figures; v2 accepted for publication in Annals of PDE | null | null | null | gr-qc math-ph math.AP math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | This paper establishes a mathematical proof of the blue-shift instability at
the sub-extremal Kerr Cauchy horizon for the linearised vacuum Einstein
equations. More precisely, we exhibit conditions on the $s=+2$ Teukolsky field,
consisting of suitable integrated upper and lower bounds on the decay along the
event horizon, that ensure that the Teukolsky field, with respect to a frame
that is regular at the Cauchy horizon, becomes singular. The conditions are in
particular satisfied by solutions of the Teukolsky equation arising from
generic and compactly supported initial data by the recent work [51] of Ma and
Zhang for slowly rotating Kerr.
| [
{
"created": "Fri, 28 Jan 2022 18:00:05 GMT",
"version": "v1"
},
{
"created": "Tue, 21 Mar 2023 09:38:27 GMT",
"version": "v2"
}
] | 2023-03-22 | [
[
"Sbierski",
"Jan",
""
]
] | This paper establishes a mathematical proof of the blue-shift instability at the sub-extremal Kerr Cauchy horizon for the linearised vacuum Einstein equations. More precisely, we exhibit conditions on the $s=+2$ Teukolsky field, consisting of suitable integrated upper and lower bounds on the decay along the event horizon, that ensure that the Teukolsky field, with respect to a frame that is regular at the Cauchy horizon, becomes singular. The conditions are in particular satisfied by solutions of the Teukolsky equation arising from generic and compactly supported initial data by the recent work [51] of Ma and Zhang for slowly rotating Kerr. |
1903.10879 | Peter Hess O | Peter O. Hess | Review on the pseudo-complex General Relativity and dark energy | 24 pages10 figures, contribution to "Dark Matter and Dark Energy in
General Relativity and Modified Theories of Gravity", Advances in High Energy
Physics, Hindawi | null | null | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A review will be presented on the algebraic extension of the standard Theory
of Relativity (GR) to the pseudo-complex formulation (pc-GR). The pc-GR
predicts the existence of a dark energy outside and inside the mass
distribution, corresponding to a modification of the GR- metric. The structure
of the emission profile of an accretion disc changes also inside a star.
Discussed are the consequences of the dark energy for cosmological models,
permitting different outcomes on the evolution of the universe.
| [
{
"created": "Mon, 25 Mar 2019 16:49:08 GMT",
"version": "v1"
}
] | 2019-03-27 | [
[
"Hess",
"Peter O.",
""
]
] | A review will be presented on the algebraic extension of the standard Theory of Relativity (GR) to the pseudo-complex formulation (pc-GR). The pc-GR predicts the existence of a dark energy outside and inside the mass distribution, corresponding to a modification of the GR- metric. The structure of the emission profile of an accretion disc changes also inside a star. Discussed are the consequences of the dark energy for cosmological models, permitting different outcomes on the evolution of the universe. |
2212.13311 | Chen-Kai Qiao | Chen-Kai Qiao, Mi Zhou | Gravitational Lensing of Schwarzschild and Charged Black Holes Immersed
in Perfect Fluid Dark Matter Halo | 31 pages, 10 figures; V2 minor revision; V3 major revision (some
errors removed) | JCAP 12 (2023) 005 | 10.1088/1475-7516/2023/12/005 | null | gr-qc astro-ph.GA | http://creativecommons.org/licenses/by-nc-nd/4.0/ | Dark matter and dark energy dominate the behavior of our universe. The dark
matter usually forms halo structures in large number of galaxies. Properties of
dark matter halo can be revealed and understood from the gravitational lensing
observations. In this work, a comprehensive study on the gravitational lensing
of black holes immersed in dark matter halos is presented. To effectively model
the supermassive black hole in a galaxy center (which is surrounded by dark
matter halo) in a simple way, we investigate the Schwarzschild black hole and
charged Reissner-Nordstr\"om black hole immersed in a perfect fluid dark matter
halo. In the present work, several basic quantities in gravitational lensing
(the gravitational deflection angle of light, photon sphere, black hole shadow
radius, gravitational lens equation and Einstein ring) are calculated and
analyzed analytically and numerically. A second order analytical expansion of
gravitational deflection angle is obtained in the weak deflection limit, and
the full gravitational deflection angle (including all order perturbation
contributions applicable to both weak and strong deflection limits) is also
calculated numerically as comparisons. It enables us to analyze the perfect
fluid dark matter influences on gravitational deflection angle and
gravitational lensing beyond the leading order, which were not sufficiently
studied in previous works. Assuming $M \sim \lambda_{\text{DM}} \sim Q$, our
results show that dark matter can greatly influence the gravitational lensing
of central black holes.
| [
{
"created": "Mon, 26 Dec 2022 22:26:38 GMT",
"version": "v1"
},
{
"created": "Thu, 2 Feb 2023 17:04:19 GMT",
"version": "v2"
},
{
"created": "Mon, 23 Oct 2023 21:02:45 GMT",
"version": "v3"
}
] | 2024-03-12 | [
[
"Qiao",
"Chen-Kai",
""
],
[
"Zhou",
"Mi",
""
]
] | Dark matter and dark energy dominate the behavior of our universe. The dark matter usually forms halo structures in large number of galaxies. Properties of dark matter halo can be revealed and understood from the gravitational lensing observations. In this work, a comprehensive study on the gravitational lensing of black holes immersed in dark matter halos is presented. To effectively model the supermassive black hole in a galaxy center (which is surrounded by dark matter halo) in a simple way, we investigate the Schwarzschild black hole and charged Reissner-Nordstr\"om black hole immersed in a perfect fluid dark matter halo. In the present work, several basic quantities in gravitational lensing (the gravitational deflection angle of light, photon sphere, black hole shadow radius, gravitational lens equation and Einstein ring) are calculated and analyzed analytically and numerically. A second order analytical expansion of gravitational deflection angle is obtained in the weak deflection limit, and the full gravitational deflection angle (including all order perturbation contributions applicable to both weak and strong deflection limits) is also calculated numerically as comparisons. It enables us to analyze the perfect fluid dark matter influences on gravitational deflection angle and gravitational lensing beyond the leading order, which were not sufficiently studied in previous works. Assuming $M \sim \lambda_{\text{DM}} \sim Q$, our results show that dark matter can greatly influence the gravitational lensing of central black holes. |
2210.00295 | Kun Meng | Kun Meng and Shao-Jun Zhang | Gravito-Electromagnetic Perturbations and QNMs of Regular Black Holes | 21 pages, 2 figures, 3 tables, references added | null | null | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In the framework of Einstein's gravity coupled to nonlinear electromagnetic
fields, we study gravito-electromagnetic perturbations of magnetic regular
black holes. The master equations of perturbations are obtained through
Chandrasekhar's procedure, in which gravitational perturbations with odd-parity
are coupled to the electromagnetic perturbations with even-parity. As an
application, we apply the master equations to obtain quasinormal modes (QNMs)
for three types of regular black holes by using numerical method. Results show
that QNMs of regular black holes depends significantly on the parameters of the
theory and the magnetic charge of the black holes and are very different from
that of the Reissner-Nordstr\"om black hole. Indications of these results on
the stability of these regular black holes are discussed in detail.
| [
{
"created": "Sat, 1 Oct 2022 14:58:13 GMT",
"version": "v1"
},
{
"created": "Sat, 8 Oct 2022 14:44:21 GMT",
"version": "v2"
}
] | 2022-10-11 | [
[
"Meng",
"Kun",
""
],
[
"Zhang",
"Shao-Jun",
""
]
] | In the framework of Einstein's gravity coupled to nonlinear electromagnetic fields, we study gravito-electromagnetic perturbations of magnetic regular black holes. The master equations of perturbations are obtained through Chandrasekhar's procedure, in which gravitational perturbations with odd-parity are coupled to the electromagnetic perturbations with even-parity. As an application, we apply the master equations to obtain quasinormal modes (QNMs) for three types of regular black holes by using numerical method. Results show that QNMs of regular black holes depends significantly on the parameters of the theory and the magnetic charge of the black holes and are very different from that of the Reissner-Nordstr\"om black hole. Indications of these results on the stability of these regular black holes are discussed in detail. |
gr-qc/0111035 | Gian Paolo Vacca | F. Finelli, G. Marozzi, G. P. Vacca and G. Venturi | Energy-Momentum Tensor of Field Fluctuations in Massive Chaotic
Inflation | revtex style, 24 pages, 6 eps figures Numerical checks added and
moduli section improved | Phys.Rev.D65:103521,2002 | 10.1103/PhysRevD.65.103521 | null | gr-qc astro-ph hep-ph hep-th | null | We study the renormalized energy-momentum tensor (EMT) of the inflaton
fluctuations in rigid space-times during the slow-rollover regime for chaotic
inflation with a mass term. We use dimensional regularization with adiabatic
subtraction and introduce a novel analytic approximation for the inflaton
fluctuations which is valid during the slow-rollover regime. Using this
approximation we find a scale invariant spectrum for the inflaton fluctuations
in a rigid space-time, and we confirm this result by numerical methods. The
resulting renormalized EMT is covariantly conserved and agrees with the
Allen-Folacci result in the de Sitter limit, when the expansion is exactly
linearly exponential in time. We analytically show that the EMT tensor of the
inflaton fluctuations grows initially in time, but saturates to the value H^2
H(0)^2, where H is the Hubble parameter and H(0) is its value when inflation
has started. This result also implies that the quantum production of light
scalar fields (with mass smaller or equal to the inflaton mass) in this model
of chaotic inflation depends on the duration of inflation and is larger than
the usual result extrapolated from the de Sitter result.
| [
{
"created": "Tue, 13 Nov 2001 14:19:41 GMT",
"version": "v1"
},
{
"created": "Tue, 27 Nov 2001 12:39:11 GMT",
"version": "v2"
}
] | 2008-11-26 | [
[
"Finelli",
"F.",
""
],
[
"Marozzi",
"G.",
""
],
[
"Vacca",
"G. P.",
""
],
[
"Venturi",
"G.",
""
]
] | We study the renormalized energy-momentum tensor (EMT) of the inflaton fluctuations in rigid space-times during the slow-rollover regime for chaotic inflation with a mass term. We use dimensional regularization with adiabatic subtraction and introduce a novel analytic approximation for the inflaton fluctuations which is valid during the slow-rollover regime. Using this approximation we find a scale invariant spectrum for the inflaton fluctuations in a rigid space-time, and we confirm this result by numerical methods. The resulting renormalized EMT is covariantly conserved and agrees with the Allen-Folacci result in the de Sitter limit, when the expansion is exactly linearly exponential in time. We analytically show that the EMT tensor of the inflaton fluctuations grows initially in time, but saturates to the value H^2 H(0)^2, where H is the Hubble parameter and H(0) is its value when inflation has started. This result also implies that the quantum production of light scalar fields (with mass smaller or equal to the inflaton mass) in this model of chaotic inflation depends on the duration of inflation and is larger than the usual result extrapolated from the de Sitter result. |
1712.08444 | A. Yu. Petrov | J. R. Nascimento, A. Yu. Petrov, P. J. Porfirio | Traversable wormholes in Chern-Simons modified gravity | 18 pages, 2 figures, revised version | null | null | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this paper, we examine the existence of traversable wormhole solutions
within the Chern-Simons modified gravity. We find a non-trivial solution in the
theory with dynamical Chern-Simons coefficient in the absence of matter
sources. This result displays a situation opposite to GR where the matter
sources violating the energy conditions are required.
| [
{
"created": "Fri, 22 Dec 2017 13:53:55 GMT",
"version": "v1"
},
{
"created": "Tue, 9 Jan 2018 13:52:13 GMT",
"version": "v2"
}
] | 2018-01-10 | [
[
"Nascimento",
"J. R.",
""
],
[
"Petrov",
"A. Yu.",
""
],
[
"Porfirio",
"P. J.",
""
]
] | In this paper, we examine the existence of traversable wormhole solutions within the Chern-Simons modified gravity. We find a non-trivial solution in the theory with dynamical Chern-Simons coefficient in the absence of matter sources. This result displays a situation opposite to GR where the matter sources violating the energy conditions are required. |
1212.3699 | Shan Bai | Shan Bai, Niall \'O Murchadha | Scaling up the extrinsic curvature in asymptotically flat gravitational
initial data: Generating trapped surfaces | 10 pages, accepted for publication in CQG | null | 10.1088/0264-9381/30/2/025013 | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The existence of the initial value constraints means that specifying initial
data for the Einstein equations is non-trivial. The standard method of
constructing initial data in the asymptotically flat case is to choose an
asymptotically flat 3-metric and a transverse-tracefree (TT) tensor on it. One
can find a conformal transformation that maps these data into solutions of the
constraints. In particular, the TT tensor becomes the extrinsic curvature of
the 3-slice. We wish to understand how the physical solution changes as the
free data is changed. In this paper we investigate an especially simple change:
we multiply the TT tensor by a large constant. One might assume that this
corresponds to pumping up the extrinsic curvature in the physical initial data.
Unexpectedly, we show that, while the conformal factor monotonically increases,
the physical extrinsic curvature decreases. The increase in the conformal
factor however means that the physical volume increases in such a way that the
ADM mass become unboundedly large. In turn, the blow-up of the mass combined
with the control we have on the extrinsic curvature allows us to show that
trapped surfaces, i.e., surfaces that are simultaneously future and past
trapped, appear in the physical initial data.
| [
{
"created": "Sat, 15 Dec 2012 16:23:42 GMT",
"version": "v1"
}
] | 2015-06-12 | [
[
"Bai",
"Shan",
""
],
[
"Murchadha",
"Niall Ó",
""
]
] | The existence of the initial value constraints means that specifying initial data for the Einstein equations is non-trivial. The standard method of constructing initial data in the asymptotically flat case is to choose an asymptotically flat 3-metric and a transverse-tracefree (TT) tensor on it. One can find a conformal transformation that maps these data into solutions of the constraints. In particular, the TT tensor becomes the extrinsic curvature of the 3-slice. We wish to understand how the physical solution changes as the free data is changed. In this paper we investigate an especially simple change: we multiply the TT tensor by a large constant. One might assume that this corresponds to pumping up the extrinsic curvature in the physical initial data. Unexpectedly, we show that, while the conformal factor monotonically increases, the physical extrinsic curvature decreases. The increase in the conformal factor however means that the physical volume increases in such a way that the ADM mass become unboundedly large. In turn, the blow-up of the mass combined with the control we have on the extrinsic curvature allows us to show that trapped surfaces, i.e., surfaces that are simultaneously future and past trapped, appear in the physical initial data. |
2402.11348 | Ayan Banerjee | Ayan Banerjee, Sudan Hansraj, Anirudh Pradhan and Abdelghani Errehymy | Is dark energy necessary for the sustainability of traversable
wormholes? | 18 pages, 10 figures, updated discussion, added references | null | null | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In the standard approach to studying wormhole geometry, the presence of dark
energy is unavoidable to ensure traversability. The dark energy provides the
negative gravity effect to keep the throat open. The question we analyse is
whether the same can be achieved without dark energy. It turns out that if we
couple the trace of energy-momentum with the standard Einstein-Hilbert
Lagrangian and utilise a sppecific equation of state then dark energy may be
obviated. The Casimir stress energy is known to result in the violation of the
null energy condition (NEC) on the energy momentum tensor. This phenomenon
makes such an equation of state (EoS) an ideal candidate to generate
traversable wormhole (WH) geometries. The laboratory proven phenomenon provides
a mechanism to sustain an open WH throat without having to appeal to dark
energy. We generate two classes of WH solutions with this in $f(R,T)$ gravity
theory, where $R$ represents the Ricci scalar and $T$ is the trace of the
stress-energy tensor. For the background geometry we choose a static and
spherically symmetric metric, and derive the field equations for exact WH
solutions. For the specific choice of the Casimir EoS relating the
energy-momentum tensor components [ Kar and Sahdev: Phys. Rev D {\bf 52} 2030
(1995)] and different choices for redshift functions, we determine the WH
geometry completely. The obtained WH solutions violate the NECs and all
qualitative constraints demanded of physically realisable WHs are satisfied.
This is demonstrated via graphical plots for a suitably chosen range of values
of the $f(R,T)$ coupling parameter. Furthermore, our study involved an
investigation into the repulsive effect of gravity, which revealed that its
presence leads to a negative deflection angle for photons traveling along null
geodesics.
| [
{
"created": "Sat, 17 Feb 2024 17:51:03 GMT",
"version": "v1"
},
{
"created": "Thu, 25 Apr 2024 09:17:06 GMT",
"version": "v2"
}
] | 2024-04-26 | [
[
"Banerjee",
"Ayan",
""
],
[
"Hansraj",
"Sudan",
""
],
[
"Pradhan",
"Anirudh",
""
],
[
"Errehymy",
"Abdelghani",
""
]
] | In the standard approach to studying wormhole geometry, the presence of dark energy is unavoidable to ensure traversability. The dark energy provides the negative gravity effect to keep the throat open. The question we analyse is whether the same can be achieved without dark energy. It turns out that if we couple the trace of energy-momentum with the standard Einstein-Hilbert Lagrangian and utilise a sppecific equation of state then dark energy may be obviated. The Casimir stress energy is known to result in the violation of the null energy condition (NEC) on the energy momentum tensor. This phenomenon makes such an equation of state (EoS) an ideal candidate to generate traversable wormhole (WH) geometries. The laboratory proven phenomenon provides a mechanism to sustain an open WH throat without having to appeal to dark energy. We generate two classes of WH solutions with this in $f(R,T)$ gravity theory, where $R$ represents the Ricci scalar and $T$ is the trace of the stress-energy tensor. For the background geometry we choose a static and spherically symmetric metric, and derive the field equations for exact WH solutions. For the specific choice of the Casimir EoS relating the energy-momentum tensor components [ Kar and Sahdev: Phys. Rev D {\bf 52} 2030 (1995)] and different choices for redshift functions, we determine the WH geometry completely. The obtained WH solutions violate the NECs and all qualitative constraints demanded of physically realisable WHs are satisfied. This is demonstrated via graphical plots for a suitably chosen range of values of the $f(R,T)$ coupling parameter. Furthermore, our study involved an investigation into the repulsive effect of gravity, which revealed that its presence leads to a negative deflection angle for photons traveling along null geodesics. |
gr-qc/9505041 | James H. Horne | Douglas M. Eardley, Eric W. Hirschmann, James H. Horne | S-Duality at the Black Hole Threshold in Gravitational Collapse | 8 pages of LaTeX, uses style "revtex"; 1 figure, available in
archive, or at ftp://ftp.itp.ucsb.edu/figures/nsf-itp-95-15.eps | Phys.Rev.D52:5397-5401,1995 | 10.1103/PhysRevD.52.R5397 | NSF-ITP-95-15 DAMTP-R95/27 | gr-qc hep-th | null | We study gravitational collapse of the axion/dilaton field in classical low
energy string theory, at the threshold for black hole formation. A new critical
solution is derived that is spherically symmetric and continuously
self-similar. The universal scaling and echoing behavior discovered by Choptuik
in gravitational collapse appear in a somewhat different form. In particular,
echoing takes the form of SL(2,R) rotations (cf. S-duality). The collapse
leaves behind an outgoing pulse of axion/dilaton radiation, with nearly but not
exactly flat spacetime within it.
| [
{
"created": "Mon, 22 May 1995 18:17:38 GMT",
"version": "v1"
}
] | 2010-01-06 | [
[
"Eardley",
"Douglas M.",
""
],
[
"Hirschmann",
"Eric W.",
""
],
[
"Horne",
"James H.",
""
]
] | We study gravitational collapse of the axion/dilaton field in classical low energy string theory, at the threshold for black hole formation. A new critical solution is derived that is spherically symmetric and continuously self-similar. The universal scaling and echoing behavior discovered by Choptuik in gravitational collapse appear in a somewhat different form. In particular, echoing takes the form of SL(2,R) rotations (cf. S-duality). The collapse leaves behind an outgoing pulse of axion/dilaton radiation, with nearly but not exactly flat spacetime within it. |
0907.3816 | Mustapha Azreg-A\"inou | M Azreg-A\"inou | Comment on `The Newtonian force experienced by a point mass near a
finite cylindrical source' | 2 pages, LaTeX | Class.Quant.Grav.26:158001,2009 | 10.1088/0264-9381/26/15/158001 | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We compare the computation times and precisions of three expansions for the
gravitational potential. The evaluation of the series by Selvaggi et al (2008
\textit{Class. Quantum Grav.} \textbf{25} 015013) is time-consuming to be
applied to the gravitational constant ($G$) or STEP experiments.
| [
{
"created": "Wed, 22 Jul 2009 11:20:01 GMT",
"version": "v1"
}
] | 2009-10-02 | [
[
"Azreg-Aïnou",
"M",
""
]
] | We compare the computation times and precisions of three expansions for the gravitational potential. The evaluation of the series by Selvaggi et al (2008 \textit{Class. Quantum Grav.} \textbf{25} 015013) is time-consuming to be applied to the gravitational constant ($G$) or STEP experiments. |
1603.00112 | Ichiro Oda | Ichiro Oda | Topological Induced Gravity | 16 pages. arXiv admin note: text overlap with arXiv:1602.03478 | null | 10.1142/S0218271817500237 | DPUR/TH/48 | gr-qc hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We propose a topological model of induced gravity (pregeometry) where both
Newton's coupling constant and the cosmological constant appear as integration
constants in solving field equations. The matter sector of a scalar field is
also considered, and by solving field equations it is shown that various types
of cosmological solutions in the FRW universe can be obtained. A detailed
analysis is given of the meaning of the BRST transformations, which make the
induced gravity be a topological field theory, by means of the canonical
quantization analysis, and the physical reason why such BRST transformations
are needed in the present formalism is clarified. Finally, we propose a
dynamical mechanism for fixing the Lagrange multiplier fields by following the
Higgs mechanism. The present study clearly indicates that the induced gravity
can be constructed at the classical level without recourse to quantum
fluctuations of matter and suggests an interesting relationship between the
induced gravity and the topological quantum field theory.
| [
{
"created": "Tue, 1 Mar 2016 02:00:08 GMT",
"version": "v1"
}
] | 2017-02-15 | [
[
"Oda",
"Ichiro",
""
]
] | We propose a topological model of induced gravity (pregeometry) where both Newton's coupling constant and the cosmological constant appear as integration constants in solving field equations. The matter sector of a scalar field is also considered, and by solving field equations it is shown that various types of cosmological solutions in the FRW universe can be obtained. A detailed analysis is given of the meaning of the BRST transformations, which make the induced gravity be a topological field theory, by means of the canonical quantization analysis, and the physical reason why such BRST transformations are needed in the present formalism is clarified. Finally, we propose a dynamical mechanism for fixing the Lagrange multiplier fields by following the Higgs mechanism. The present study clearly indicates that the induced gravity can be constructed at the classical level without recourse to quantum fluctuations of matter and suggests an interesting relationship between the induced gravity and the topological quantum field theory. |
gr-qc/0207051 | Marcelo S. Berman | Marcelo Samuel Berman and Luis A. Trevisan | Inflationary Lambda-Universe with Time Varying Fundamental Constants | 8 pages including front cover | null | null | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Barrow, and Barrow and collaborators, have put forward theoretical models
with variable fundamental constants including JBD theories. The experimental
evidence for an accelerating Universe points out to a deceleration parameter
approximately equal to -- 1. On the other hand, there is evidence for a time
varying fine structure constant alpha . We have included the above results in a
JBD cosmological model modified by J.D. Barrow by including a time varying
speed of light, thus, finding an exponential inflationary phase with variables
G, alpha and c . This means that the primordial value of alpha was
exponentially larger than its present value. Planck`s time may not be then
approximately 10 to the power - 43 s ; the same may happen to other Planck`s
quantities. We found an exponentially time-decaying Cosmological term.
| [
{
"created": "Fri, 12 Jul 2002 14:54:57 GMT",
"version": "v1"
},
{
"created": "Mon, 15 Jul 2002 20:42:22 GMT",
"version": "v2"
},
{
"created": "Sat, 25 Jul 2009 23:58:08 GMT",
"version": "v3"
},
{
"created": "Mon, 27 Jul 2009 23:17:48 GMT",
"version": "v4"
},
{
"created": "Sat, 8 Aug 2009 13:53:47 GMT",
"version": "v5"
},
{
"created": "Wed, 23 Sep 2009 10:20:29 GMT",
"version": "v6"
}
] | 2009-09-23 | [
[
"Berman",
"Marcelo Samuel",
""
],
[
"Trevisan",
"Luis A.",
""
]
] | Barrow, and Barrow and collaborators, have put forward theoretical models with variable fundamental constants including JBD theories. The experimental evidence for an accelerating Universe points out to a deceleration parameter approximately equal to -- 1. On the other hand, there is evidence for a time varying fine structure constant alpha . We have included the above results in a JBD cosmological model modified by J.D. Barrow by including a time varying speed of light, thus, finding an exponential inflationary phase with variables G, alpha and c . This means that the primordial value of alpha was exponentially larger than its present value. Planck`s time may not be then approximately 10 to the power - 43 s ; the same may happen to other Planck`s quantities. We found an exponentially time-decaying Cosmological term. |
1108.4519 | Kourosh Nozari | Kourosh Nozari and Faeze Kiani | On the cosmological viability of the Hu-Sawicki type modified induced
gravity | 17 pages, 2 figures, accepted for publication in Phys. Lett. B | Phys.Lett.B703:395-401,2011 | 10.1016/j.physletb.2011.08.020 | null | gr-qc astro-ph.CO hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | It has been shown recently that the normal branch of a DGP braneworld
scenario self-accelerates if the induced gravity on the brane is modified in
the spirit of $f(R)$ modified gravity. Within this viewpoint, we investigate
cosmological viability of the Hu-Sawicki type modified induced gravity.
Firstly, we present a dynamical system analysis of a general $f(R)$-DGP model.
We show that in the phase space of the model, there exist three standard
critical points; one of which is a de Sitter point corresponding to
accelerating phase of the universe expansion. The stability of this point
depends on the effective equation of state parameter of the curvature fluid. If
we consider the curvature fluid to be a canonical scalar field in the
equivalent scalar-tensor theory, the mentioned de Sitter phase is unstable,
otherwise it is an attractor, stable phase. We show that the effective equation
of state parameter of the model realizes an effective phantom-like behavior. A
cosmographic analysis shows that this model, which admits a stable de Sitter
phase in its expansion history, is a cosmologically viable scenario.
| [
{
"created": "Tue, 23 Aug 2011 07:55:09 GMT",
"version": "v1"
}
] | 2011-09-27 | [
[
"Nozari",
"Kourosh",
""
],
[
"Kiani",
"Faeze",
""
]
] | It has been shown recently that the normal branch of a DGP braneworld scenario self-accelerates if the induced gravity on the brane is modified in the spirit of $f(R)$ modified gravity. Within this viewpoint, we investigate cosmological viability of the Hu-Sawicki type modified induced gravity. Firstly, we present a dynamical system analysis of a general $f(R)$-DGP model. We show that in the phase space of the model, there exist three standard critical points; one of which is a de Sitter point corresponding to accelerating phase of the universe expansion. The stability of this point depends on the effective equation of state parameter of the curvature fluid. If we consider the curvature fluid to be a canonical scalar field in the equivalent scalar-tensor theory, the mentioned de Sitter phase is unstable, otherwise it is an attractor, stable phase. We show that the effective equation of state parameter of the model realizes an effective phantom-like behavior. A cosmographic analysis shows that this model, which admits a stable de Sitter phase in its expansion history, is a cosmologically viable scenario. |
2312.03811 | Matthew J. Lake Dr | Matthew J. Lake and Marek Miller | Quantum reference frames, revisited | 95 pages, including 13 pages of references. 13 figures. Comments
welcome | null | null | null | gr-qc hep-ph quant-ph | http://creativecommons.org/licenses/by/4.0/ | The topic of quantum reference frames (QRFs) has attracted a great deal of
attention in the recent literature. Potentially, the correct description of
such frames is important for both the technological applications of quantum
mechanics and for its foundations, including the search for a future theory of
quantum gravity. In this letter, we point out potential inconsistencies in the
mainstream approach to this subject and propose an alternative definition that
avoids these problems. Crucially, we reject the notion that transformations
between QRFs can be represented by unitary operators and explain the clear
physical reasons for this. An experimental protocol, capable of empirically
distinguishing between competing definitions of the term, is also proposed. The
implications of the new model, for uncertainty relations, spacetime symmetries,
gauge symmetries, the quantisation of gravity, and other foundational issues
are discussed, and possible directions for future work in this field are
considered.
| [
{
"created": "Wed, 6 Dec 2023 18:15:52 GMT",
"version": "v1"
}
] | 2023-12-08 | [
[
"Lake",
"Matthew J.",
""
],
[
"Miller",
"Marek",
""
]
] | The topic of quantum reference frames (QRFs) has attracted a great deal of attention in the recent literature. Potentially, the correct description of such frames is important for both the technological applications of quantum mechanics and for its foundations, including the search for a future theory of quantum gravity. In this letter, we point out potential inconsistencies in the mainstream approach to this subject and propose an alternative definition that avoids these problems. Crucially, we reject the notion that transformations between QRFs can be represented by unitary operators and explain the clear physical reasons for this. An experimental protocol, capable of empirically distinguishing between competing definitions of the term, is also proposed. The implications of the new model, for uncertainty relations, spacetime symmetries, gauge symmetries, the quantisation of gravity, and other foundational issues are discussed, and possible directions for future work in this field are considered. |
gr-qc/0012001 | Spiros Cotsakis | Spiros Cotsakis and John Miritzis | Algebraic integrability of FRW-scalar cosmologies | Research announcement, 2 pages, submitted for publication in the MG9
Proceedings | null | null | null | gr-qc | null | For dynamical systems of dimension three or more the question of
integrability or nonintegrability is extended by the possibility of chaotic
behaviour in the general solution. We determine the integrability of isotropic
cosmological models in general relativity and string theory with a variety of
matter terms, by a performance of the Painlev\'{e} analysis in an effort to
examine whether or not there exists a Laurent expansion of the solution about a
movable pole which contains the number of arbitrary constants necessary for a
general solution.
| [
{
"created": "Fri, 1 Dec 2000 11:29:02 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Cotsakis",
"Spiros",
""
],
[
"Miritzis",
"John",
""
]
] | For dynamical systems of dimension three or more the question of integrability or nonintegrability is extended by the possibility of chaotic behaviour in the general solution. We determine the integrability of isotropic cosmological models in general relativity and string theory with a variety of matter terms, by a performance of the Painlev\'{e} analysis in an effort to examine whether or not there exists a Laurent expansion of the solution about a movable pole which contains the number of arbitrary constants necessary for a general solution. |
gr-qc/0702056 | Calvin Smith | Christopher J. Fewster and Calvin J. Smith | Absolute quantum energy inequalities in curved spacetime | 31 pages. Corrections and clarifications added. Final version to
appear in Ann. H. Poincare | AnnalesHenriPoincare9:425-455,2008 | 10.1007/s00023-008-0361-0 | null | gr-qc | null | Quantum Energy Inequalities (QEIs) are results which limit the extent to
which the smeared renormalised energy density of the quantum field can be
negative, when averaged along a timelike curve or over a more general timelike
submanifold in spacetime. On globally hyperbolic spacetimes the
minimally-coupled massive quantum Klein--Gordon field is known to obey a
`difference' QEI that depends on a reference state chosen arbitrarily from the
class of Hadamard states. In many spacetimes of interest this bound cannot be
evaluated explicitly. In this paper we obtain the first `absolute' QEI for the
minimally-coupled massive quantum Klein--Gordon field on four dimensional
globally hyperbolic spacetimes; that is, a bound which depends only on the
local geometry. The argument is an adaptation of that used to prove the
difference QEI and utilises the Sobolev wave-front set to give a complete
characterisation of the singularities of the Hadamard series. Moreover, the
bound is explicit and can be formulated covariantly under additional (general)
conditions. We also generalise our results to incorporate adiabatic states.
| [
{
"created": "Fri, 9 Feb 2007 12:43:33 GMT",
"version": "v1"
},
{
"created": "Thu, 22 Feb 2007 17:00:01 GMT",
"version": "v2"
},
{
"created": "Thu, 20 Dec 2007 09:42:54 GMT",
"version": "v3"
}
] | 2008-11-26 | [
[
"Fewster",
"Christopher J.",
""
],
[
"Smith",
"Calvin J.",
""
]
] | Quantum Energy Inequalities (QEIs) are results which limit the extent to which the smeared renormalised energy density of the quantum field can be negative, when averaged along a timelike curve or over a more general timelike submanifold in spacetime. On globally hyperbolic spacetimes the minimally-coupled massive quantum Klein--Gordon field is known to obey a `difference' QEI that depends on a reference state chosen arbitrarily from the class of Hadamard states. In many spacetimes of interest this bound cannot be evaluated explicitly. In this paper we obtain the first `absolute' QEI for the minimally-coupled massive quantum Klein--Gordon field on four dimensional globally hyperbolic spacetimes; that is, a bound which depends only on the local geometry. The argument is an adaptation of that used to prove the difference QEI and utilises the Sobolev wave-front set to give a complete characterisation of the singularities of the Hadamard series. Moreover, the bound is explicit and can be formulated covariantly under additional (general) conditions. We also generalise our results to incorporate adiabatic states. |
2209.14484 | Stephen Adler | Stephen L. Adler | Equation of state, and atomic electron effective potential, for a Weyl
scaling invariant dark energy | 10 pages. Sec. I Introduction expanded. Sec. II on w and the figures
are new. Secs. III and IV are the original 2208.14484 with minor edits. This
posting will be submitted for publication | null | null | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A key attribute of dark energy is the equation of state parameter $w={\rm
pressure}/{\rm energy~density}$, and this has been recently measured
observationally, giving values close to $-1$. In this paper we calculate the
$w$ parameter characterizing the novel Weyl scaling invariant dark energy that
we have analyzed in a series of papers, and show that it is compatible with
experiment. We also derive the atomic electron effective potential induced by
dark energy from the electron geodesic equation, which can be applied to the
evaluation of energy level shifts in Rydberg atoms.
| [
{
"created": "Thu, 29 Sep 2022 00:30:11 GMT",
"version": "v1"
},
{
"created": "Wed, 21 Feb 2024 20:02:40 GMT",
"version": "v2"
},
{
"created": "Sat, 15 Jun 2024 02:40:30 GMT",
"version": "v3"
}
] | 2024-06-18 | [
[
"Adler",
"Stephen L.",
""
]
] | A key attribute of dark energy is the equation of state parameter $w={\rm pressure}/{\rm energy~density}$, and this has been recently measured observationally, giving values close to $-1$. In this paper we calculate the $w$ parameter characterizing the novel Weyl scaling invariant dark energy that we have analyzed in a series of papers, and show that it is compatible with experiment. We also derive the atomic electron effective potential induced by dark energy from the electron geodesic equation, which can be applied to the evaluation of energy level shifts in Rydberg atoms. |
1802.09073 | Mariafelicia De Laurentis Professor | Mariafelicia De Laurentis | Noether's stars in $f(\cal {R})$ gravity | 7 pages, 4 figures, accepted for publication in Physics Letter B | null | 10.1016/j.physletb.2018.03.001 | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The Noether Symmetry Approach can be used to construct spherically symmetric
solutions in $f({\cal R})$ gravity. Specifically, the Noether conserved
quantity is related to the gravitational mass and a gravitational radius that
reduces to the Schwarzschild radius in the limit $f({\cal R})\rightarrow {\cal
R}$. We show that it is possible to construct the $M-R$ relation for neutron
stars depending on the Noether conserved quantity and the associated
gravitational radius. This approach enables the recovery of extreme massive
stars that could not be stable in the standard Tolman-Oppenheimer-Volkoff based
on General Relativity. Examples are given for some power law $f({\cal R})$
gravity models.
| [
{
"created": "Sun, 25 Feb 2018 20:37:07 GMT",
"version": "v1"
}
] | 2018-04-04 | [
[
"De Laurentis",
"Mariafelicia",
""
]
] | The Noether Symmetry Approach can be used to construct spherically symmetric solutions in $f({\cal R})$ gravity. Specifically, the Noether conserved quantity is related to the gravitational mass and a gravitational radius that reduces to the Schwarzschild radius in the limit $f({\cal R})\rightarrow {\cal R}$. We show that it is possible to construct the $M-R$ relation for neutron stars depending on the Noether conserved quantity and the associated gravitational radius. This approach enables the recovery of extreme massive stars that could not be stable in the standard Tolman-Oppenheimer-Volkoff based on General Relativity. Examples are given for some power law $f({\cal R})$ gravity models. |
gr-qc/9408033 | Jorma Louko | Jorma Louko | Chern-Simons functional and the no-boundary proposal in Bianchi IX
quantum cosmology | 9 pages, REVTeX v3.0. (One reference added.) | Phys.Rev.D51:586-590,1995 | 10.1103/PhysRevD.51.586 | WISC-MILW-94-TH-20 | gr-qc hep-th | null | The Chern-Simons functional $S_{\rm CS}$ is an exact solution to the
Ashtekar-Hamilton-Jacobi equation of general relativity with a nonzero
cosmological constant. In this paper we consider $S_{\rm CS}$ in Bianchi type
IX cosmology with $S^3$ spatial surfaces. We show that among the classical
solutions generated by~$S_{\rm CS}$, there is a two-parameter family of
Euclidean spacetimes that have a regular NUT-type closing. When two of the
three scale factors are equal, these spacetimes reduce to a one-parameter
family within the Euclidean Taub-NUT-de~Sitter metrics. For a nonzero
cosmological constant, $\exp(iS_{\rm CS})$ therefore provides a semiclassical
estimate to the Bianchi~IX no-boundary wave function in Ashtekar's variables.
| [
{
"created": "Fri, 26 Aug 1994 03:22:18 GMT",
"version": "v1"
},
{
"created": "Wed, 15 Feb 1995 01:27:42 GMT",
"version": "v2"
}
] | 2010-11-01 | [
[
"Louko",
"Jorma",
""
]
] | The Chern-Simons functional $S_{\rm CS}$ is an exact solution to the Ashtekar-Hamilton-Jacobi equation of general relativity with a nonzero cosmological constant. In this paper we consider $S_{\rm CS}$ in Bianchi type IX cosmology with $S^3$ spatial surfaces. We show that among the classical solutions generated by~$S_{\rm CS}$, there is a two-parameter family of Euclidean spacetimes that have a regular NUT-type closing. When two of the three scale factors are equal, these spacetimes reduce to a one-parameter family within the Euclidean Taub-NUT-de~Sitter metrics. For a nonzero cosmological constant, $\exp(iS_{\rm CS})$ therefore provides a semiclassical estimate to the Bianchi~IX no-boundary wave function in Ashtekar's variables. |
gr-qc/0702133 | Yosef Zlochower | Manuela Campanelli, Carlos O. Lousto, Yosef Zlochower, David Merritt | Maximum gravitational recoil | 4 pages, 4 figs, revtex4 | Phys.Rev.Lett.98:231102,2007 | 10.1103/PhysRevLett.98.231102 | null | gr-qc astro-ph | null | Recent calculations of gravitational radiation recoil generated during
black-hole binary mergers have reopened the possibility that a merged binary
can be ejected even from the nucleus of a massive host galaxy. Here we report
the first systematic study of gravitational recoil of equal-mass binaries with
equal, but anti-aligned, spins parallel to the orbital plane. Such an
orientation of the spins is expected to maximize the recoil. We find that
recoil velocity (which is perpendicular to the orbital plane) varies
sinusoidally with the angle that the initial spin directions make with the
initial linear momenta of each hole and scales up to a maximum of ~4000 km/s
for maximally-rotating holes. Our results show that the amplitude of the recoil
velocity can depend sensitively on spin orientations of the black holes prior
to merger.
| [
{
"created": "Sun, 25 Feb 2007 20:48:58 GMT",
"version": "v1"
},
{
"created": "Tue, 27 Feb 2007 23:52:41 GMT",
"version": "v2"
}
] | 2010-04-06 | [
[
"Campanelli",
"Manuela",
""
],
[
"Lousto",
"Carlos O.",
""
],
[
"Zlochower",
"Yosef",
""
],
[
"Merritt",
"David",
""
]
] | Recent calculations of gravitational radiation recoil generated during black-hole binary mergers have reopened the possibility that a merged binary can be ejected even from the nucleus of a massive host galaxy. Here we report the first systematic study of gravitational recoil of equal-mass binaries with equal, but anti-aligned, spins parallel to the orbital plane. Such an orientation of the spins is expected to maximize the recoil. We find that recoil velocity (which is perpendicular to the orbital plane) varies sinusoidally with the angle that the initial spin directions make with the initial linear momenta of each hole and scales up to a maximum of ~4000 km/s for maximally-rotating holes. Our results show that the amplitude of the recoil velocity can depend sensitively on spin orientations of the black holes prior to merger. |
gr-qc/0402040 | Yuichirou Sekiguchi | Masaru Shibata and Yu-ichirou Sekiguchi | Gravitational waves from axisymmetric rotating stellar core collapse to
a neutron star in full general relativity | Phys. Rev. D in press | Phys.Rev.D69:084024,2004 | 10.1103/PhysRevD.69.084024 | null | gr-qc astro-ph | null | Axisymmetric numerical simulations of rotating stellar core collapse to a
neutron star are performed in the framework of full general relativity. The
so-called Cartoon method, in which the Einstein field equations are solved in
the Cartesian coordinates and the axisymmetric condition is imposed around the
$y=0$ plane, is adopted. The hydrodynamic equations are solved in the
cylindrical coordinates (on the $y=0$ plane in the Cartesian coordinates) using
a high-resolution shock-capturing scheme with the maximum grid size
$(2500,2500)$. A parametric equation of state is adopted to model collapsing
stellar cores and neutron stars following Dimmelmeier et al. It is found that
the evolution of central density during the collapse, bounce, and formation of
protoneutron stars agree well with those in the work of Dimmelmeier et al. in
which an approximate general relativistic formulation is adopted. This
indicates that such approximation is appropriate for following axisymmetric
stellar core collapses and subsequent formation of protoneutron stars.
Gravitational waves are computed using a quadrupole formula. It is found that
the waveforms are qualitatively in good agreement with those by Dimmelmeier et
al. However, quantitatively, two waveforms do not agree well. Possible reasons
for the disagreement are discussed.
| [
{
"created": "Sun, 8 Feb 2004 12:23:13 GMT",
"version": "v1"
}
] | 2011-07-18 | [
[
"Shibata",
"Masaru",
""
],
[
"Sekiguchi",
"Yu-ichirou",
""
]
] | Axisymmetric numerical simulations of rotating stellar core collapse to a neutron star are performed in the framework of full general relativity. The so-called Cartoon method, in which the Einstein field equations are solved in the Cartesian coordinates and the axisymmetric condition is imposed around the $y=0$ plane, is adopted. The hydrodynamic equations are solved in the cylindrical coordinates (on the $y=0$ plane in the Cartesian coordinates) using a high-resolution shock-capturing scheme with the maximum grid size $(2500,2500)$. A parametric equation of state is adopted to model collapsing stellar cores and neutron stars following Dimmelmeier et al. It is found that the evolution of central density during the collapse, bounce, and formation of protoneutron stars agree well with those in the work of Dimmelmeier et al. in which an approximate general relativistic formulation is adopted. This indicates that such approximation is appropriate for following axisymmetric stellar core collapses and subsequent formation of protoneutron stars. Gravitational waves are computed using a quadrupole formula. It is found that the waveforms are qualitatively in good agreement with those by Dimmelmeier et al. However, quantitatively, two waveforms do not agree well. Possible reasons for the disagreement are discussed. |
2311.03315 | Indranil Chakraborty | Soumya Bhattacharya, Debanjan Bose, Indranil Chakraborty, Arpan Hait,
and Subhendra Mohanty | Gravitational memory signal from neutrino self-interactions in supernova | 12 pages, 3 figures, comments are welcome | null | null | null | gr-qc astro-ph.HE hep-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Neutrinos with large self-interactions, arising from exchange of light
scalars or vectors with mass $M_\phi\simeq 10{\rm MeV}$, can play a useful role
in cosmology for structure formation and solving the Hubble tension. It has
been proposed that large self-interactions of neutrinos may change the observed
properties of supernova like the neutrino luminosity or the duration of the
neutrino burst. In this paper, we study the gravitational wave memory signal
arising from supernova neutrinos. Our results reveal that memory signal for
self-interacting neutrinos are weaker than free-streaming neutrinos in the high
frequency range. Implications for detecting and differentiating between such
signals for planned space-borne detectors, DECIGO and BBO, are also discussed.
| [
{
"created": "Mon, 6 Nov 2023 18:08:19 GMT",
"version": "v1"
}
] | 2023-11-07 | [
[
"Bhattacharya",
"Soumya",
""
],
[
"Bose",
"Debanjan",
""
],
[
"Chakraborty",
"Indranil",
""
],
[
"Hait",
"Arpan",
""
],
[
"Mohanty",
"Subhendra",
""
]
] | Neutrinos with large self-interactions, arising from exchange of light scalars or vectors with mass $M_\phi\simeq 10{\rm MeV}$, can play a useful role in cosmology for structure formation and solving the Hubble tension. It has been proposed that large self-interactions of neutrinos may change the observed properties of supernova like the neutrino luminosity or the duration of the neutrino burst. In this paper, we study the gravitational wave memory signal arising from supernova neutrinos. Our results reveal that memory signal for self-interacting neutrinos are weaker than free-streaming neutrinos in the high frequency range. Implications for detecting and differentiating between such signals for planned space-borne detectors, DECIGO and BBO, are also discussed. |
2210.09254 | Jamie Bamber | Jamie Bamber, Josu C. Aurrekoetxea, Katy Clough, Pedro G. Ferreira | Black hole merger simulations in wave dark matter environments | 9 pages, 5 figures, 1 appendix, 2 movies:
https://youtube.com/playlist?list=PLSkfizpQDrcb8Zd7C9yEfnMpnKQk7I9ts Comments
welcome! | null | 10.1103/PhysRevD.107.024035 | null | gr-qc astro-ph.CO hep-th | http://creativecommons.org/licenses/by/4.0/ | The interaction of binary black hole mergers with their environments can be
studied using numerical relativity simulations. These start only a short finite
time before merger, at which point appropriate initial conditions must be
imposed. A key task is therefore to identify the configuration that is
appropriate for the binary and its environment at this stage of the evolution.
In this work we study the behaviour of wave dark matter around equal mass black
hole binaries, finding that there is a preferred, quasi-stationary profile that
persists and grows over multiple orbits, in contrast to heavier mass dark
matter where any overdensity tends to be dispersed by the binary motion. Whilst
different initial configurations converge to the preferred quasi-stationary one
after several orbits, unwanted transient oscillations are generated in the
process, which may impact on the signal in short simulation runs. We also point
out that naively superimposing the matter onto a circular binary results in
artificially eccentric orbits due to the matter backreaction, which is an
effect of the initial conditions and not a signature of dark matter. We discuss
the further work required so that comparison of waveforms obtained with
environments to vacuum cases can be done in a meaningful way.
| [
{
"created": "Mon, 17 Oct 2022 16:51:13 GMT",
"version": "v1"
}
] | 2023-02-08 | [
[
"Bamber",
"Jamie",
""
],
[
"Aurrekoetxea",
"Josu C.",
""
],
[
"Clough",
"Katy",
""
],
[
"Ferreira",
"Pedro G.",
""
]
] | The interaction of binary black hole mergers with their environments can be studied using numerical relativity simulations. These start only a short finite time before merger, at which point appropriate initial conditions must be imposed. A key task is therefore to identify the configuration that is appropriate for the binary and its environment at this stage of the evolution. In this work we study the behaviour of wave dark matter around equal mass black hole binaries, finding that there is a preferred, quasi-stationary profile that persists and grows over multiple orbits, in contrast to heavier mass dark matter where any overdensity tends to be dispersed by the binary motion. Whilst different initial configurations converge to the preferred quasi-stationary one after several orbits, unwanted transient oscillations are generated in the process, which may impact on the signal in short simulation runs. We also point out that naively superimposing the matter onto a circular binary results in artificially eccentric orbits due to the matter backreaction, which is an effect of the initial conditions and not a signature of dark matter. We discuss the further work required so that comparison of waveforms obtained with environments to vacuum cases can be done in a meaningful way. |
gr-qc/0501106 | Victor Varela | V. Varela | Neutral perfect fluids of Majumdar-type in general relativity | 9 pages | Gen.Rel.Grav. 37 (2005) 1769-1777 | 10.1007/s10714-005-0157-1 | null | gr-qc | null | We consider the extension of the Majumdar-type class of static solutions for
the Einstein-Maxwell equations, proposed by Ida to include charged perfect
fluid sources. We impose the equation of state $\rho+3p=0$ and discuss
spherically symmetric solutions for the linear potential equation satisfied by
the metric. In this particular case the fluid charge density vanishes and we
locate the arising neutral perfect fluid in the intermediate region defined by
two thin shells with respective charges $Q$ and $-Q$. With its innermost flat
and external (Schwarzschild) asymptotically flat spacetime regions, the
resultant condenser-like geometries resemble solutions discussed by Cohen and
Cohen in a different context. We explore this relationship and point out an
exotic gravitational property of our neutral perfect fluid. We mention possible
continuations of this study to embrace non-spherically symmetric situations and
higher dimensional spacetimes.
| [
{
"created": "Mon, 31 Jan 2005 20:07:44 GMT",
"version": "v1"
}
] | 2009-11-11 | [
[
"Varela",
"V.",
""
]
] | We consider the extension of the Majumdar-type class of static solutions for the Einstein-Maxwell equations, proposed by Ida to include charged perfect fluid sources. We impose the equation of state $\rho+3p=0$ and discuss spherically symmetric solutions for the linear potential equation satisfied by the metric. In this particular case the fluid charge density vanishes and we locate the arising neutral perfect fluid in the intermediate region defined by two thin shells with respective charges $Q$ and $-Q$. With its innermost flat and external (Schwarzschild) asymptotically flat spacetime regions, the resultant condenser-like geometries resemble solutions discussed by Cohen and Cohen in a different context. We explore this relationship and point out an exotic gravitational property of our neutral perfect fluid. We mention possible continuations of this study to embrace non-spherically symmetric situations and higher dimensional spacetimes. |
2112.02654 | Pierre-Henri Chavanis | Pierre-Henri Chavanis | The self-gravitating Fermi gas in Newtonian gravity and general
relativity | null | null | null | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We review the history of the self-gravitating Fermi gas in Newtonian gravity
and general relativity. We mention applications to white dwarfs, neutron stars
and dark matter halos. We describe the nature of instabilities and phase
transitions in the self-gravitating Fermi gas as energy (microcanonical
ensemble) or temperature (canonical ensemble) is reduced. When $N<N_{\rm OV}$,
where $N_{\rm OV}$ is the Oppenheimer-Volkoff critical particle number, the
self-gravitating Fermi gas experiences a gravothermal catastrophe at $E_c$
stopped by quantum mechanics (Pauli's exclusion principle). The equilibrium
state has a core-halo structure made of a quantum core (degenerate fermion
ball) surrounded by a classical isothermal halo. When $N>N_{\rm OV}$, a new
turning point appears at an energy $E"_c$ below which the system experiences a
gravitational collapse towards a black hole [P.H. Chavanis, G. Alberti, Phys.
Lett. B 801, 135155 (2020)]. When $N_{\rm OV}<N<N'_*$, the self-gravitating
Fermi gas experiences a gravothermal catastrophe at $E_c$ leading to a fermion
ball, then a gravitational collapse at $E''_c$ leading to a black hole. When
$N>N'_*$, the condensed branch disappears and the instability at $E_c$ directly
leads to a black hole. We discuss implications of these results for dark matter
halos made of massive neutrinos.
| [
{
"created": "Sun, 5 Dec 2021 19:05:04 GMT",
"version": "v1"
}
] | 2021-12-07 | [
[
"Chavanis",
"Pierre-Henri",
""
]
] | We review the history of the self-gravitating Fermi gas in Newtonian gravity and general relativity. We mention applications to white dwarfs, neutron stars and dark matter halos. We describe the nature of instabilities and phase transitions in the self-gravitating Fermi gas as energy (microcanonical ensemble) or temperature (canonical ensemble) is reduced. When $N<N_{\rm OV}$, where $N_{\rm OV}$ is the Oppenheimer-Volkoff critical particle number, the self-gravitating Fermi gas experiences a gravothermal catastrophe at $E_c$ stopped by quantum mechanics (Pauli's exclusion principle). The equilibrium state has a core-halo structure made of a quantum core (degenerate fermion ball) surrounded by a classical isothermal halo. When $N>N_{\rm OV}$, a new turning point appears at an energy $E"_c$ below which the system experiences a gravitational collapse towards a black hole [P.H. Chavanis, G. Alberti, Phys. Lett. B 801, 135155 (2020)]. When $N_{\rm OV}<N<N'_*$, the self-gravitating Fermi gas experiences a gravothermal catastrophe at $E_c$ leading to a fermion ball, then a gravitational collapse at $E''_c$ leading to a black hole. When $N>N'_*$, the condensed branch disappears and the instability at $E_c$ directly leads to a black hole. We discuss implications of these results for dark matter halos made of massive neutrinos. |
1606.08183 | Li-E Qiang | Li-E Qiang | Secular Gravity Gradients in Non-Dynamical Chern-Simons Modified Gravity
for Satellite Gradiometry Measurements | 11 pages, 1 figure | null | null | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | With continuous advances in related technologies, relativistic gravitational
experiments with orbiting gradiometers becomes feasible, which could naturally
be incorporated into future satellite gravity missions. Tests of Chern-Simons
modified gravity are meaningful since such a modification gives us insights
into (possible) parity-violations in gravitation. In this work, we derive, at
the post-Newtonian level, the new observables of secular gradients from the
non-dynamical Chern-Simons modified gravity, which will greatly improve the
constraint on the mass scale $M_{CS}$ that may be drawn from satellite
gradiometry measurements. For superconducting gradiometers, a strong bound
$M_{CS}\geq 10^{-7}\ eV$ could in principle be obtained. For future optical
gradiometers based on similar technologies from the LISA PathFinder mission, a
even stronger bound $M_{CS}\geq 10^{-6}\sim 10^{-5}\ eV$ might be expected.
| [
{
"created": "Mon, 27 Jun 2016 09:59:44 GMT",
"version": "v1"
},
{
"created": "Wed, 29 Jun 2016 03:46:58 GMT",
"version": "v2"
}
] | 2016-06-30 | [
[
"Qiang",
"Li-E",
""
]
] | With continuous advances in related technologies, relativistic gravitational experiments with orbiting gradiometers becomes feasible, which could naturally be incorporated into future satellite gravity missions. Tests of Chern-Simons modified gravity are meaningful since such a modification gives us insights into (possible) parity-violations in gravitation. In this work, we derive, at the post-Newtonian level, the new observables of secular gradients from the non-dynamical Chern-Simons modified gravity, which will greatly improve the constraint on the mass scale $M_{CS}$ that may be drawn from satellite gradiometry measurements. For superconducting gradiometers, a strong bound $M_{CS}\geq 10^{-7}\ eV$ could in principle be obtained. For future optical gradiometers based on similar technologies from the LISA PathFinder mission, a even stronger bound $M_{CS}\geq 10^{-6}\sim 10^{-5}\ eV$ might be expected. |
0709.1400 | Orchidea Maria Lecian | O. M. Lecian, G. Montani | Dark Energy as a Relic of the Vacuum-Energy Cancellation? | 24 pages, 2 figures, to appear on IJMPD | Int.J.Mod.Phys.D17:111-133,2008 | 10.1142/S0218271808011900 | null | gr-qc | null | We analyze the dynamical implications of an exponential Lagrangian density
for the gravitational field, as referred to an isotropic FRW Universe. Then, we
discuss the features of the generalized deSitter phase, predicted by the new
Friedmann equation. The existence of a consistent deSitter solution arises only
if the ratio between the vacuum-energy density and that associated with the
fundamental length of the theory acquires a tantalizing negative character.
This choice allows us to explain the present universe dark energy as a relic of
the vacuum-energy cancellation due to the cosmological constant intrinsically
contained in our scheme. The corresponding scalar-tensor description of the
model is addressed too, and the behavior of the scalar field is analyzed for
both negative and positive values of the cosmological term. In the first case,
the Friedmann equation is studied both in vacuum and in presence of external
matter, while, in the second case, the quantum regime is approached in the
framework of ''repulsive'' properties of the gravitational interaction, as
described in recent issues in Loop Quantum Cosmology. In particular, in the
vacuum case, we find a pure non-Einsteinian effect, according to which a
negative cosmological constant provides an accelerating deSitter dynamics, in
the region where the series expansion of the exponential term does not hold.
| [
{
"created": "Mon, 10 Sep 2007 14:01:45 GMT",
"version": "v1"
}
] | 2008-11-26 | [
[
"Lecian",
"O. M.",
""
],
[
"Montani",
"G.",
""
]
] | We analyze the dynamical implications of an exponential Lagrangian density for the gravitational field, as referred to an isotropic FRW Universe. Then, we discuss the features of the generalized deSitter phase, predicted by the new Friedmann equation. The existence of a consistent deSitter solution arises only if the ratio between the vacuum-energy density and that associated with the fundamental length of the theory acquires a tantalizing negative character. This choice allows us to explain the present universe dark energy as a relic of the vacuum-energy cancellation due to the cosmological constant intrinsically contained in our scheme. The corresponding scalar-tensor description of the model is addressed too, and the behavior of the scalar field is analyzed for both negative and positive values of the cosmological term. In the first case, the Friedmann equation is studied both in vacuum and in presence of external matter, while, in the second case, the quantum regime is approached in the framework of ''repulsive'' properties of the gravitational interaction, as described in recent issues in Loop Quantum Cosmology. In particular, in the vacuum case, we find a pure non-Einsteinian effect, according to which a negative cosmological constant provides an accelerating deSitter dynamics, in the region where the series expansion of the exponential term does not hold. |
1306.0374 | Domenico Giulini J.W. | Domenico Giulini | Does cosmological expansion affect local physics? | 39 pages, 6 figures. Based on a talk delivered at the conference on
"Philosophical Aspects of Modern Cosmology", held in Granada, 22-23 September
2011. In version 2 references were added and updated. Also, a new final
subsection on "black-hole cosmology" was added | Studies in History and Philosophy of Modern Physics Volume 46,
Part A, May 2014, Pages 24-37 | 10.1016/j.shpsb.2013.09.009 | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this contribution I wish to address the question whether, and how, the
global cosmological expansion influences local physics. I argue that a pseudo
Newtonian picture can be quite accurate if "expansion" is taken to be an
attribute of the inertial structure rather than of "space" in some
substantivalist sense. This contradicts the often-heard suggestion to imagine
cosmological expansion as that of "space itself". Regarding General Relativity,
I emphasise the need for proper geometric characterisations in order to
meaningfully compare localised systems in different spacetimes, like black
holes in static and expanding environments. Examples of this sort are discussed
in some detail to clearly map out the problems.
| [
{
"created": "Mon, 3 Jun 2013 12:11:27 GMT",
"version": "v1"
},
{
"created": "Thu, 3 Oct 2013 13:00:23 GMT",
"version": "v2"
}
] | 2014-09-10 | [
[
"Giulini",
"Domenico",
""
]
] | In this contribution I wish to address the question whether, and how, the global cosmological expansion influences local physics. I argue that a pseudo Newtonian picture can be quite accurate if "expansion" is taken to be an attribute of the inertial structure rather than of "space" in some substantivalist sense. This contradicts the often-heard suggestion to imagine cosmological expansion as that of "space itself". Regarding General Relativity, I emphasise the need for proper geometric characterisations in order to meaningfully compare localised systems in different spacetimes, like black holes in static and expanding environments. Examples of this sort are discussed in some detail to clearly map out the problems. |
0907.4146 | Theodore A. Jacobson | Ted Jacobson and Thomas P. Sotiriou | Over-spinning a black hole with a test body | 4 pages; v2: reference added, incorporates the missed case of an
oblate test body, which appears with the published version only as an
erratum, other minor edits (with respect to v1) | Phys. Rev. Lett. 103, 141101 (2009); 103, 209903(E) (2009) | 10.1103/PhysRevLett.103.141101 | null | gr-qc astro-ph.HE hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | It has long been known that a maximally spinning black hole can not be
over-spun by tossing in a test body. Here we show that if instead the black
hole starts out with below maximal spin, then indeed over-spinning can be
achieved when adding either orbital or spin angular momentum. We find that
requirements on the size and internal structure of the test body can be met as
well. Our analysis neglects radiative and self-force effects,which may prevent
the over-spinning.
| [
{
"created": "Thu, 23 Jul 2009 19:56:39 GMT",
"version": "v1"
},
{
"created": "Tue, 1 Dec 2009 22:58:20 GMT",
"version": "v2"
}
] | 2009-12-02 | [
[
"Jacobson",
"Ted",
""
],
[
"Sotiriou",
"Thomas P.",
""
]
] | It has long been known that a maximally spinning black hole can not be over-spun by tossing in a test body. Here we show that if instead the black hole starts out with below maximal spin, then indeed over-spinning can be achieved when adding either orbital or spin angular momentum. We find that requirements on the size and internal structure of the test body can be met as well. Our analysis neglects radiative and self-force effects,which may prevent the over-spinning. |
gr-qc/9610050 | null | Cristian Martinez, Jorge Zanelli | Back-reaction of a conformal field on a three-dimensional black hole | 12 pages, RevTeX, no figures | Phys.Rev. D55 (1997) 3642-3646 | 10.1103/PhysRevD.55.3642 | null | gr-qc | null | The first order corrections to the geometry of the (2+1)-dimensional black
hole due to back-reaction of a massless conformal scalar field are computed.
The renormalized stress energy tensor used as the source of Einstein equations
is computed with the Green function for the black-hole background with
transparent boundary conditions. This tensor has the same functional form as
the one found in the nonperturbative case which can be exactly solved. Thus, a
static, circularly symmetric and asymptotically anti-de Sitter black hole
solution of the semiclassical equations is found. The corrections to the
thermodynamic quantities are also computed.
| [
{
"created": "Tue, 22 Oct 1996 22:12:00 GMT",
"version": "v1"
}
] | 2009-10-28 | [
[
"Martinez",
"Cristian",
""
],
[
"Zanelli",
"Jorge",
""
]
] | The first order corrections to the geometry of the (2+1)-dimensional black hole due to back-reaction of a massless conformal scalar field are computed. The renormalized stress energy tensor used as the source of Einstein equations is computed with the Green function for the black-hole background with transparent boundary conditions. This tensor has the same functional form as the one found in the nonperturbative case which can be exactly solved. Thus, a static, circularly symmetric and asymptotically anti-de Sitter black hole solution of the semiclassical equations is found. The corrections to the thermodynamic quantities are also computed. |
gr-qc/0205070 | Victor Hugo Cardenas | Victor H. Cardenas | Protecting the Holographic Principle: Inflation | 10 pages, 2 figures. To appear in Physics Letter B | null | null | UCV-IF 02/03 | gr-qc astro-ph | null | A scenario where inflation emerges as a response to protect the holographic
principle is described. A two fluid model in a closed universe inflation
picture is assumed, and a possible explanation for secondary exponential
expansion phases as those currently observed is given.
| [
{
"created": "Thu, 16 May 2002 13:32:17 GMT",
"version": "v1"
},
{
"created": "Wed, 9 Apr 2003 19:17:13 GMT",
"version": "v2"
}
] | 2007-05-23 | [
[
"Cardenas",
"Victor H.",
""
]
] | A scenario where inflation emerges as a response to protect the holographic principle is described. A two fluid model in a closed universe inflation picture is assumed, and a possible explanation for secondary exponential expansion phases as those currently observed is given. |
gr-qc/9608022 | Hideo Kodama | Hideo Kodama(Yukawa Institute) and Takashi Hamazaki(Dept. of Phys.,
Kyoto University) | Evolution of cosmological perturbations in a stage dominated by an
oscillatory scalar field | Revised version, 23 pages, no figure, plain LaTeX, minor errors in
some equations are corrected, no change in the main results and the
conclusion | Prog.Theor.Phys. 96 (1996) 949-970 | 10.1143/PTP.96.949 | YITP-96-28, KUNS 1406 | gr-qc | null | In the investigation of the evolution of cosmological perturbations in
inflationary universe models the behavior of perturbations during the reheating
stage is the most unclear point. In particular in the early reheating phase in
which a rapidly oscillating scalar field dominates the energy density, the
behavior of perturbations are not known well because their evolution equation
expressed in terms of the curvature perturbation becomes singular. In this
paper it is shown that in spite of this singular behavior of the evolution
equation the Bardeen parameter stays constant in a good accuracy during this
stage for superhorizon-scale perturbations except for a sequence of negligibly
short intervals around the zero points of the time derivative of the scalar
field. This justifies the conventional formula relating the amplitudes of
quantum fluctuations during inflation and those of adiabatic perturbations at
horizon crossing in the Friedmann stage, except for possible corrections
produced by the energy transfer from the scalar field to radiation in the late
stage of reheating. It is further shown that outside the above sequence of time
intervals the behavior of the perturbations coincides in a good accuracy with
that for a perfect fluid system obtained from the original scalar field system
by the WKB approximation and a spacetime averaging over a Hubble horizon scale.
| [
{
"created": "Fri, 9 Aug 1996 07:56:40 GMT",
"version": "v1"
},
{
"created": "Fri, 27 Sep 1996 07:11:49 GMT",
"version": "v2"
}
] | 2009-10-28 | [
[
"Kodama",
"Hideo",
"",
"Yukawa Institute"
],
[
"Hamazaki",
"Takashi",
"",
"Dept. of Phys.,\n Kyoto University"
]
] | In the investigation of the evolution of cosmological perturbations in inflationary universe models the behavior of perturbations during the reheating stage is the most unclear point. In particular in the early reheating phase in which a rapidly oscillating scalar field dominates the energy density, the behavior of perturbations are not known well because their evolution equation expressed in terms of the curvature perturbation becomes singular. In this paper it is shown that in spite of this singular behavior of the evolution equation the Bardeen parameter stays constant in a good accuracy during this stage for superhorizon-scale perturbations except for a sequence of negligibly short intervals around the zero points of the time derivative of the scalar field. This justifies the conventional formula relating the amplitudes of quantum fluctuations during inflation and those of adiabatic perturbations at horizon crossing in the Friedmann stage, except for possible corrections produced by the energy transfer from the scalar field to radiation in the late stage of reheating. It is further shown that outside the above sequence of time intervals the behavior of the perturbations coincides in a good accuracy with that for a perfect fluid system obtained from the original scalar field system by the WKB approximation and a spacetime averaging over a Hubble horizon scale. |
2007.00026 | Ufuk Aydemir | Ufuk Aydemir | Primordial Black-Hole Mimicker in Quadratic Gravity as Dark Matter | 24 pages, 3 figures. Invited talk at Corfu Summer Institute 2019
"School and Workshops on Elementary Particle Physics and Gravity"
(CORFU2019), 31 August - 25 September 2019, Corfu, Greece. Based mainly on
arXiv:2003.10682; slightly different presentation and some complementary
remarks | null | null | null | gr-qc astro-ph.CO astro-ph.HE hep-ph hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We discuss the astrophysical and cosmological implications of having
primordial thermal 2-2-hole remnants as dark matter. Thermal 2-2-holes emanate
in quadratic gravity as horizonless classical solutions for ultracompact
distributions of relativistic thermal gas. In contrast to a large 2-2-hole that
imitates the thermodynamic behaviour of a black hole, a small 2-2-hole at late
stages of evaporation behaves as a stable remnant with the mass approaching a
minimal value. These remnants as all dark matter can satisfy the corresponding
observational constraints provided that both the formation and remnant masses
are relatively small. The parameter space for the remnant mass is probed
through possible remnant mergers that would produce strong fluxes of
high-energy astrophysical particles; the high-energy photon and neutrino data
appear to favor towards the Planck-mass remnants, pointing to the
strong-coupling scenario for the quantum theory of quadratic gravity. The
formation mass, on the other hand, is constrained by the early-universe
cosmology, which turns out to require 2-2-holes to evolve into the remnant
state before Big Bang Nucleosynthesis.
| [
{
"created": "Tue, 30 Jun 2020 18:01:15 GMT",
"version": "v1"
}
] | 2020-07-02 | [
[
"Aydemir",
"Ufuk",
""
]
] | We discuss the astrophysical and cosmological implications of having primordial thermal 2-2-hole remnants as dark matter. Thermal 2-2-holes emanate in quadratic gravity as horizonless classical solutions for ultracompact distributions of relativistic thermal gas. In contrast to a large 2-2-hole that imitates the thermodynamic behaviour of a black hole, a small 2-2-hole at late stages of evaporation behaves as a stable remnant with the mass approaching a minimal value. These remnants as all dark matter can satisfy the corresponding observational constraints provided that both the formation and remnant masses are relatively small. The parameter space for the remnant mass is probed through possible remnant mergers that would produce strong fluxes of high-energy astrophysical particles; the high-energy photon and neutrino data appear to favor towards the Planck-mass remnants, pointing to the strong-coupling scenario for the quantum theory of quadratic gravity. The formation mass, on the other hand, is constrained by the early-universe cosmology, which turns out to require 2-2-holes to evolve into the remnant state before Big Bang Nucleosynthesis. |
1312.2279 | Viktor G. Czinner | Viktor G. Czinner | Thick Dirac-Nambu-Goto branes on black hole backgrounds | 4 pages, 2 figures, Proceedings of the Spanish Relativity Meeting in
Portugal ERE2012 | Progress in Mathematical Relativity, Gravitation and Cosmology,
Springer Proceedings in Mathematics & Statistics Volume 60, 2014, pp 223-226 | 10.1007/978-3-642-40157-2_28 | null | gr-qc hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Thickness corrections to static, axisymmetric Dirac-Nambu-Goto branes
embedded into spherically symmetric black hole spacetimes with arbitrary number
of dimensions are studied. First, by applying a perturbative approximation, it
is found that the thick solutions deviate significantly in their analytic
properties from the thin ones near the axis of the system, and perturbative
approaches around the thin configurations can not provide regular thick
solutions above a certain dimension. For the general case, a non-perturbative,
numerical approach is applied and regular solutions are obtained for arbitrary
brane and bulk dimensions. As a special case, it has been found that
2-dimensional branes are exceptional, as they share their analytic properties
with the thin branes rather than the thick solutions of all other dimensions.
| [
{
"created": "Sun, 8 Dec 2013 23:26:01 GMT",
"version": "v1"
}
] | 2013-12-13 | [
[
"Czinner",
"Viktor G.",
""
]
] | Thickness corrections to static, axisymmetric Dirac-Nambu-Goto branes embedded into spherically symmetric black hole spacetimes with arbitrary number of dimensions are studied. First, by applying a perturbative approximation, it is found that the thick solutions deviate significantly in their analytic properties from the thin ones near the axis of the system, and perturbative approaches around the thin configurations can not provide regular thick solutions above a certain dimension. For the general case, a non-perturbative, numerical approach is applied and regular solutions are obtained for arbitrary brane and bulk dimensions. As a special case, it has been found that 2-dimensional branes are exceptional, as they share their analytic properties with the thin branes rather than the thick solutions of all other dimensions. |
gr-qc/9812024 | Don Marolf | Domenico Giulini and Donald Marolf | On the Generality of Refined Algebraic Quantization | 12 pages, no figures, ReVTeX, some changes in presentation, some
references added | Class.Quant.Grav.16:2479-2488,1999 | 10.1088/0264-9381/16/7/321 | ZU-TH-98/20 | gr-qc | null | The Dirac quantization `procedure' for constrained systems is well known to
have many subtleties and ambiguities. Within this ill-defined framework, we
explore the generality of a particular interpretation of the Dirac procedure
known as refined algebraic quantization. We find technical conditions under
which refined algebraic quantization can reproduce the general implementation
of the Dirac scheme for systems whose constraints form a Lie algebra with
structure constants. The main result is that, under appropriate conditions, the
choice of an inner product on the physical states is equivalent to the choice
of a ``rigging map'' in refined algebraic quantization.
| [
{
"created": "Mon, 7 Dec 1998 14:17:44 GMT",
"version": "v1"
},
{
"created": "Mon, 31 May 1999 20:13:22 GMT",
"version": "v2"
}
] | 2008-11-26 | [
[
"Giulini",
"Domenico",
""
],
[
"Marolf",
"Donald",
""
]
] | The Dirac quantization `procedure' for constrained systems is well known to have many subtleties and ambiguities. Within this ill-defined framework, we explore the generality of a particular interpretation of the Dirac procedure known as refined algebraic quantization. We find technical conditions under which refined algebraic quantization can reproduce the general implementation of the Dirac scheme for systems whose constraints form a Lie algebra with structure constants. The main result is that, under appropriate conditions, the choice of an inner product on the physical states is equivalent to the choice of a ``rigging map'' in refined algebraic quantization. |
2302.00229 | Zu-Cheng Chen | Yu-Mei Wu, Zu-Cheng Chen, Qing-Guo Huang | Search for Stochastic Gravitational-Wave Background from Massive Gravity
in the NANOGrav 12.5-Year Data Set | 7 pages, 2 figures, 1 table; accepted for publication in Phys. Rev. D | null | 10.1103/PhysRevD.107.042003 | null | gr-qc astro-ph.CO astro-ph.GA astro-ph.HE hep-ph | http://creativecommons.org/licenses/by/4.0/ | Gravitational waves offer a new window to probe the nature of gravity,
including answering if the mediating particle, graviton, has a non-zero mass or
not. Pulsar timing arrays measure stochastic gravitational wave background
(SGWB) at $\sim1-100$~nanohertz. Recently, the North American Nanohertz
Observatory for Gravitational Waves (NANOGrav) collaboration reported an
uncorrelated common-spectrum process in their 12.5-year data set with no
substantial evidence that the process comes from the SGWB predicted by general
relativity. In this work, we explore the possibility of an SGWB from massive
gravity in the data set and find that a massless graviton is preferred because
of the relatively larger Bayes factor. Without statistically significant
evidence for dispersion-related correlations predicted by massive gravity, we
place upper limits on the amplitude of the SGWB for graviton mass smaller than
$10^{-23}$~eV as $A_{\rm{MG}}<3.21\times 10^{-15}$ at $95\%$ confidence level.
| [
{
"created": "Wed, 1 Feb 2023 04:19:54 GMT",
"version": "v1"
}
] | 2023-03-01 | [
[
"Wu",
"Yu-Mei",
""
],
[
"Chen",
"Zu-Cheng",
""
],
[
"Huang",
"Qing-Guo",
""
]
] | Gravitational waves offer a new window to probe the nature of gravity, including answering if the mediating particle, graviton, has a non-zero mass or not. Pulsar timing arrays measure stochastic gravitational wave background (SGWB) at $\sim1-100$~nanohertz. Recently, the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) collaboration reported an uncorrelated common-spectrum process in their 12.5-year data set with no substantial evidence that the process comes from the SGWB predicted by general relativity. In this work, we explore the possibility of an SGWB from massive gravity in the data set and find that a massless graviton is preferred because of the relatively larger Bayes factor. Without statistically significant evidence for dispersion-related correlations predicted by massive gravity, we place upper limits on the amplitude of the SGWB for graviton mass smaller than $10^{-23}$~eV as $A_{\rm{MG}}<3.21\times 10^{-15}$ at $95\%$ confidence level. |
1306.5974 | P. A. Gonzalez | Ramon Becar, P. A. Gonzalez and Y. Vasquez | Dirac quasinormal modes of Chern-Simons and BTZ black holes with torsion | Version accepted for publication in PRD | Phys. Rev. D 89, 023001 (2014) | 10.1103/PhysRevD.89.023001 | null | gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study Chern-Simons black holes in d-dimensions and we calculate
analytically the quasinormal modes of fermionic perturbations. Also, we
consider as background the five-dimensional Chern-Simons black hole with
torsion and the BTZ black hole with torsion. We have found that the quasinormal
modes depend on the highest power of curvature present in the Chern-Simons
theory, such as occurs for the quasinormal modes of scalar perturbations. We
also show that the effect of the torsion is to modify the real part of the
quasinormal frequencies, which modify the oscillation frequency of the field
for the five dimensional case. However, for the BTZ black hole with torsion,
the effect is to modify the imaginary part of these frequencies, that is, the
relaxation time for the decay of the black hole perturbation. The imaginary
part of the quasinormal frequencies is negative which guaranties the stability
of these black holes under fermionic field perturbations.
| [
{
"created": "Tue, 25 Jun 2013 14:14:58 GMT",
"version": "v1"
},
{
"created": "Sun, 21 Jul 2013 01:35:36 GMT",
"version": "v2"
},
{
"created": "Sun, 8 Dec 2013 15:01:32 GMT",
"version": "v3"
}
] | 2014-01-15 | [
[
"Becar",
"Ramon",
""
],
[
"Gonzalez",
"P. A.",
""
],
[
"Vasquez",
"Y.",
""
]
] | We study Chern-Simons black holes in d-dimensions and we calculate analytically the quasinormal modes of fermionic perturbations. Also, we consider as background the five-dimensional Chern-Simons black hole with torsion and the BTZ black hole with torsion. We have found that the quasinormal modes depend on the highest power of curvature present in the Chern-Simons theory, such as occurs for the quasinormal modes of scalar perturbations. We also show that the effect of the torsion is to modify the real part of the quasinormal frequencies, which modify the oscillation frequency of the field for the five dimensional case. However, for the BTZ black hole with torsion, the effect is to modify the imaginary part of these frequencies, that is, the relaxation time for the decay of the black hole perturbation. The imaginary part of the quasinormal frequencies is negative which guaranties the stability of these black holes under fermionic field perturbations. |
gr-qc/0309098 | Diego Pavon | German Izquierdo and Diego Pavon | Mini Black Holes and the Relic Gravitational Waves Spectrum | 19 pages, 2 figures. To be published in section D of the Physical
Review | Phys.Rev. D68 (2003) 124005 | 10.1103/PhysRevD.68.124005 | null | gr-qc astro-ph hep-ph | null | In this paper we explore the impact of an era -right after reheating-
dominated by mini black holes and radiation on the spectrum of the relic
gravitational waves. This era may lower the spectrum several orders of
magnitude.
| [
{
"created": "Fri, 19 Sep 2003 13:45:07 GMT",
"version": "v1"
}
] | 2009-11-10 | [
[
"Izquierdo",
"German",
""
],
[
"Pavon",
"Diego",
""
]
] | In this paper we explore the impact of an era -right after reheating- dominated by mini black holes and radiation on the spectrum of the relic gravitational waves. This era may lower the spectrum several orders of magnitude. |
gr-qc/9404038 | Hans-Juergen Schmidt | Hans - Juergen Schmidt | Stability and Hamiltonian formulation of higher derivative theories | 38 pages, LaTeX, no figures, Phys. Rev. D 49 (1994) 6354; the Erratum
Phys. Rev. D 54 (1996) 7906 clarifies that a spatially flat Friedmann model
need not be geodesically complete even if the scale factor a(t) is positive
and smooth for all real values of the synchronized time t | Phys.Rev.D49:6354,1994; Erratum-ibid.D54:7906,1996;
Phys.Rev.D54:7906,1996 | 10.1103/PhysRevD.49.6354 10.1103/PhysRevD.54.7906 | null | gr-qc | null | We analyze the presumptions which lead to instabilities in theories of order
higher than second. That type of fourth order gravity which leads to an
inflationary (quasi de Sitter) period of cosmic evolution by inclusion of one
curvature squared term (i.e. the Starobinsky model) is used as an example. The
corresponding Hamiltonian formulation (which is necessary for deducing the
Wheeler de Witt equation) is found both in the Ostrogradski approach and in
another form. As an example, a closed form solution of the Wheeler de Witt
equation for a spatially flat Friedmann model and L=R\sp 2 is found. The method
proposed by Simon to bring fourth order gravity to second order can be (if
suitably generalized) applied to bring sixth order gravity to second order. In
the Erratum we show that a spatially flat Friedmann model need not be
geodesically complete even if the scale factor a(t) is positive and smooth for
all real values of the synchronized time t.
| [
{
"created": "Tue, 19 Apr 1994 16:30:25 GMT",
"version": "v1"
},
{
"created": "Mon, 3 Mar 1997 13:51:02 GMT",
"version": "v2"
}
] | 2014-11-17 | [
[
"Schmidt",
"Hans - Juergen",
""
]
] | We analyze the presumptions which lead to instabilities in theories of order higher than second. That type of fourth order gravity which leads to an inflationary (quasi de Sitter) period of cosmic evolution by inclusion of one curvature squared term (i.e. the Starobinsky model) is used as an example. The corresponding Hamiltonian formulation (which is necessary for deducing the Wheeler de Witt equation) is found both in the Ostrogradski approach and in another form. As an example, a closed form solution of the Wheeler de Witt equation for a spatially flat Friedmann model and L=R\sp 2 is found. The method proposed by Simon to bring fourth order gravity to second order can be (if suitably generalized) applied to bring sixth order gravity to second order. In the Erratum we show that a spatially flat Friedmann model need not be geodesically complete even if the scale factor a(t) is positive and smooth for all real values of the synchronized time t. |
gr-qc/0304031 | Huguet Eric | T. Garidi, E. Huguet, J. Renaud | De Sitter Waves and the Zero Curvature Limit | 9 pages, latex no figure, to appear in Phys. Rev. D | Phys.Rev. D67 (2003) 124028 | 10.1103/PhysRevD.67.124028 | null | gr-qc | null | We show that a particular set of global modes for the massive de Sitter
scalar field (the de Sitter waves) allows to manage the group representations
and the Fourier transform in the flat (Minkowskian) limit. This is in
opposition to the usual acceptance based on a previous result, suggesting the
appearance of negative energy in the limit process. This method also confirms
that the Euclidean vacuum, in de Sitter spacetime, has to be preferred as far
as one wishes to recover ordinary QFT in the flat limit.
| [
{
"created": "Mon, 7 Apr 2003 10:51:08 GMT",
"version": "v1"
}
] | 2009-11-10 | [
[
"Garidi",
"T.",
""
],
[
"Huguet",
"E.",
""
],
[
"Renaud",
"J.",
""
]
] | We show that a particular set of global modes for the massive de Sitter scalar field (the de Sitter waves) allows to manage the group representations and the Fourier transform in the flat (Minkowskian) limit. This is in opposition to the usual acceptance based on a previous result, suggesting the appearance of negative energy in the limit process. This method also confirms that the Euclidean vacuum, in de Sitter spacetime, has to be preferred as far as one wishes to recover ordinary QFT in the flat limit. |
2010.07059 | Marc Geiller | Marc Geiller, Etera R. Livine, Francesco Sartini | Symmetries of the Black Hole Interior and Singularity Regularization | 46 pages, 6 figures | SciPost Phys. 10, 022 (2021) | 10.21468/SciPostPhys.10.1.022 | null | gr-qc hep-th | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We reveal an $\mathfrak{iso}(2,1)$ Poincar\'e algebra of conserved charges
associated with the dynamics of the interior of black holes. The action of
these Noether charges integrates to a symmetry of the gravitational system
under the Poincar\'e group ISO$(2,1)$, which allows to describe the evolution
of the geometry inside the black hole in terms of geodesics and horocycles of
AdS${}_2$. At the Lagrangian level, this symmetry corresponds to M\"obius
transformations of the proper time together with translations. Remarkably, this
is a physical symmetry changing the state of the system, which also naturally
forms a subgroup of the much larger
$\textrm{BMS}_{3}=\textrm{Diff}(S^1)\ltimes\textrm{Vect}(S^1)$ group, where
$S^1$ is the compactified time axis. It is intriguing to discover this
structure for the black hole interior, and this hints at a fundamental role of
BMS symmetry for black hole physics. The existence of this symmetry provides a
powerful criterion to discriminate between different regularization and
quantization schemes. Following loop quantum cosmology, we identify a
regularized set of variables and Hamiltonian for the black hole interior, which
allows to resolve the singularity in a black-to-white hole transition while
preserving the Poincar\'e symmetry on phase space. This unravels new aspects of
symmetry for black holes, and opens the way towards a rigorous group
quantization of the interior.
| [
{
"created": "Wed, 14 Oct 2020 13:07:14 GMT",
"version": "v1"
},
{
"created": "Fri, 15 Jan 2021 13:56:04 GMT",
"version": "v2"
}
] | 2021-02-01 | [
[
"Geiller",
"Marc",
""
],
[
"Livine",
"Etera R.",
""
],
[
"Sartini",
"Francesco",
""
]
] | We reveal an $\mathfrak{iso}(2,1)$ Poincar\'e algebra of conserved charges associated with the dynamics of the interior of black holes. The action of these Noether charges integrates to a symmetry of the gravitational system under the Poincar\'e group ISO$(2,1)$, which allows to describe the evolution of the geometry inside the black hole in terms of geodesics and horocycles of AdS${}_2$. At the Lagrangian level, this symmetry corresponds to M\"obius transformations of the proper time together with translations. Remarkably, this is a physical symmetry changing the state of the system, which also naturally forms a subgroup of the much larger $\textrm{BMS}_{3}=\textrm{Diff}(S^1)\ltimes\textrm{Vect}(S^1)$ group, where $S^1$ is the compactified time axis. It is intriguing to discover this structure for the black hole interior, and this hints at a fundamental role of BMS symmetry for black hole physics. The existence of this symmetry provides a powerful criterion to discriminate between different regularization and quantization schemes. Following loop quantum cosmology, we identify a regularized set of variables and Hamiltonian for the black hole interior, which allows to resolve the singularity in a black-to-white hole transition while preserving the Poincar\'e symmetry on phase space. This unravels new aspects of symmetry for black holes, and opens the way towards a rigorous group quantization of the interior. |
gr-qc/0703038 | Sigbjorn Hervik | S Hervik, R J van den Hoogen, W C Lim and A A Coley | Late-time behaviour of the tilted Bianchi type VIh models | 35 pages, 14 figures; v2:added more comments and refs, typos
corrected | Class.Quant.Grav.24:3859-3896,2007 | 10.1088/0264-9381/24/15/007 | null | gr-qc astro-ph hep-th | null | We study tilted perfect fluid cosmological models with a constant equation of
state parameter in spatially homogeneous models of Bianchi type VI_h using
dynamical systems methods and numerical experimentation, with an emphasis on
their future asymptotic evolution. We determine all of the equilibrium points
of the type VI_h state space (which correspond to exact self-similar solutions
of the Einstein equations, some of which are new), and their stability is
investigated. We find that there are vacuum plane-wave solutions that act as
future attractors. In the parameter space, a `loophole' is shown to exist in
which there are no stable equilibrium points. We then show that a
Hopf-bifurcation can occur resulting in a stable closed orbit (which we refer
to as the Mussel attractor) corresponding to points both inside the loophole
and points just outside the loophole; in the former case the closed curves act
as late-time attractors while in the latter case these attracting curves will
co-exist with attracting equilibrium points. In the special Bianchi type III
case, centre manifold theory is required to determine the future attractors.
Comprehensive numerical experiments are carried out to complement and confirm
the analytical results presented. We note that the Bianchi type VI_h case is of
particular interest in that it contains many different subcases which exhibit
many of the different possible future asymptotic behaviours of Bianchi
cosmological models.
| [
{
"created": "Tue, 6 Mar 2007 13:55:33 GMT",
"version": "v1"
},
{
"created": "Wed, 18 Jul 2007 14:04:49 GMT",
"version": "v2"
}
] | 2008-11-26 | [
[
"Hervik",
"S",
""
],
[
"Hoogen",
"R J van den",
""
],
[
"Lim",
"W C",
""
],
[
"Coley",
"A A",
""
]
] | We study tilted perfect fluid cosmological models with a constant equation of state parameter in spatially homogeneous models of Bianchi type VI_h using dynamical systems methods and numerical experimentation, with an emphasis on their future asymptotic evolution. We determine all of the equilibrium points of the type VI_h state space (which correspond to exact self-similar solutions of the Einstein equations, some of which are new), and their stability is investigated. We find that there are vacuum plane-wave solutions that act as future attractors. In the parameter space, a `loophole' is shown to exist in which there are no stable equilibrium points. We then show that a Hopf-bifurcation can occur resulting in a stable closed orbit (which we refer to as the Mussel attractor) corresponding to points both inside the loophole and points just outside the loophole; in the former case the closed curves act as late-time attractors while in the latter case these attracting curves will co-exist with attracting equilibrium points. In the special Bianchi type III case, centre manifold theory is required to determine the future attractors. Comprehensive numerical experiments are carried out to complement and confirm the analytical results presented. We note that the Bianchi type VI_h case is of particular interest in that it contains many different subcases which exhibit many of the different possible future asymptotic behaviours of Bianchi cosmological models. |
1004.1973 | Arturo Stabile | A. Stabile | The Post-Newtonian Limit of f(R)-gravity in the Harmonic Gauge | 16 pages, 10 figures | Phys.Rev.D82:064021,2010 | 10.1103/PhysRevD.82.064021 | null | gr-qc astro-ph.EP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A general analytic procedure is developed for the post-Newtonian limit of
$f(R)$-gravity with metric approach in the Jordan frame by using the harmonic
gauge condition. In a pure perturbative framework and by using the Green
function method a general scheme of solutions up to $(v/c)^4$ order is shown.
Considering the Taylor expansion of a generic function $f$ it is possible to
parameterize the solutions by derivatives of $f$. At Newtonian order,
$(v/c)^2$, all more important topics about the Gauss and Birkhoff theorem are
discussed. The corrections to "standard" gravitational potential
($tt$-component of metric tensor) generated by an extended uniform mass
ball-like source are calculated up to $(v/c)^4$ order. The corrections, Yukawa
and oscillating-like, are found inside and outside the mass distribution. At
last when the limit $f\rightarrow R$ is considered the $f(R)$-gravity converges
in General Relativity at level of Lagrangian, field equations and their
solutions.
| [
{
"created": "Mon, 12 Apr 2010 14:34:20 GMT",
"version": "v1"
},
{
"created": "Tue, 1 Jun 2010 20:16:12 GMT",
"version": "v2"
}
] | 2014-11-20 | [
[
"Stabile",
"A.",
""
]
] | A general analytic procedure is developed for the post-Newtonian limit of $f(R)$-gravity with metric approach in the Jordan frame by using the harmonic gauge condition. In a pure perturbative framework and by using the Green function method a general scheme of solutions up to $(v/c)^4$ order is shown. Considering the Taylor expansion of a generic function $f$ it is possible to parameterize the solutions by derivatives of $f$. At Newtonian order, $(v/c)^2$, all more important topics about the Gauss and Birkhoff theorem are discussed. The corrections to "standard" gravitational potential ($tt$-component of metric tensor) generated by an extended uniform mass ball-like source are calculated up to $(v/c)^4$ order. The corrections, Yukawa and oscillating-like, are found inside and outside the mass distribution. At last when the limit $f\rightarrow R$ is considered the $f(R)$-gravity converges in General Relativity at level of Lagrangian, field equations and their solutions. |
gr-qc/0606100 | Xiao-Gang Wen | Zheng-Cheng Gu and Xiao-Gang Wen | A lattice bosonic model as a quantum theory of gravity | 4 pages. RevTeX4. Homepage http://dao.mit.edu/~wen | null | null | null | gr-qc cond-mat.str-el hep-th | null | A local quantum bosonic model on a lattice is constructed whose low energy
excitations are gravitons described by linearized Einstein action. Thus the
bosonic model is a quantum theory of gravity, at least at the linear level. We
find that the compactification and the discretization of metric tenor are
crucial in obtaining a quantum theory of gravity.
| [
{
"created": "Fri, 23 Jun 2006 00:15:57 GMT",
"version": "v1"
}
] | 2007-05-23 | [
[
"Gu",
"Zheng-Cheng",
""
],
[
"Wen",
"Xiao-Gang",
""
]
] | A local quantum bosonic model on a lattice is constructed whose low energy excitations are gravitons described by linearized Einstein action. Thus the bosonic model is a quantum theory of gravity, at least at the linear level. We find that the compactification and the discretization of metric tenor are crucial in obtaining a quantum theory of gravity. |
1508.01402 | Raul Vera | Borja Reina and Ra\"ul Vera | On the mass of rotating stars in Newtonian gravity and GR | 11 pages, uses iopart style and a custom bibtex style | null | 10.1088/0264-9381/33/1/017001 | null | gr-qc astro-ph.HE | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We show how the correction to the calculation of the mass in the original
relativistic model of a rotating star by Hartle [6], found recently [10],
appears in the Newtonian limit, and that the correcting term is indeed present,
albeit hidden, in the original Newtonian approach by Chandrasekhar [2].
| [
{
"created": "Thu, 6 Aug 2015 13:55:12 GMT",
"version": "v1"
}
] | 2015-12-16 | [
[
"Reina",
"Borja",
""
],
[
"Vera",
"Raül",
""
]
] | We show how the correction to the calculation of the mass in the original relativistic model of a rotating star by Hartle [6], found recently [10], appears in the Newtonian limit, and that the correcting term is indeed present, albeit hidden, in the original Newtonian approach by Chandrasekhar [2]. |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.