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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1712.06872
|
Robert T Thompson
|
Robert T. Thompson
|
Covariant electrodynamics in linear media: Optical metric
| null |
Phys. Rev. D 97, 065001 (2018)
|
10.1103/PhysRevD.97.065001
| null |
gr-qc physics.optics
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
While the postulate of covariance of Maxwell's equations for all inertial
observers led Einstein to special relativity, it was the further demand of
general covariance -- form invariance under general coordinate transformations,
including between accelerating frames -- that led to general relativity.
Several lines of inquiry over the past two decades, notably the development of
metamaterial-based transformation optics, has spurred a greater interest in the
role of geometry and space-time covariance for electrodynamics in ponderable
media. I develop a generally covariant, coordinate-free framework for
electrodynamics in general dielectric media residing in curved background
space-times. In particular, I derive a relation for the spatial medium
parameters measured by an arbitrary time-like observer. In terms of those
medium parameters I derive an explicit expression for the Finsler-like optical
metric of birefringent media and show how it reduces to a Riemann-like optical
metric for nonbirefringent media. This formulation provides a basis for a
unified approach to ray and congruence tracing through media in curved
space-times that may smoothly vary among positively refracting, negatively
refracting, and vacuum.
|
[
{
"created": "Tue, 19 Dec 2017 11:31:22 GMT",
"version": "v1"
},
{
"created": "Thu, 8 Mar 2018 21:01:30 GMT",
"version": "v2"
}
] |
2018-03-12
|
[
[
"Thompson",
"Robert T.",
""
]
] |
While the postulate of covariance of Maxwell's equations for all inertial observers led Einstein to special relativity, it was the further demand of general covariance -- form invariance under general coordinate transformations, including between accelerating frames -- that led to general relativity. Several lines of inquiry over the past two decades, notably the development of metamaterial-based transformation optics, has spurred a greater interest in the role of geometry and space-time covariance for electrodynamics in ponderable media. I develop a generally covariant, coordinate-free framework for electrodynamics in general dielectric media residing in curved background space-times. In particular, I derive a relation for the spatial medium parameters measured by an arbitrary time-like observer. In terms of those medium parameters I derive an explicit expression for the Finsler-like optical metric of birefringent media and show how it reduces to a Riemann-like optical metric for nonbirefringent media. This formulation provides a basis for a unified approach to ray and congruence tracing through media in curved space-times that may smoothly vary among positively refracting, negatively refracting, and vacuum.
|
1906.07113
|
Isha Kotecha
|
Goffredo Chirco and Isha Kotecha
|
Generalized Gibbs Ensembles in Discrete Quantum Gravity
|
8 pages; Springer LNCS format; invited contribution to the conference
proceedings of GSI 2019, to be published in Springer's LNCS series: Geometric
Science of Information 2019, ed. F. Nielsen and F. Barbaresco
| null |
10.1007/978-3-030-26980-7
| null |
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Maximum entropy principle and Souriau's symplectic generalization of Gibbs
states have provided crucial insights leading to extensions of standard
equilibrium statistical mechanics and thermodynamics. In this brief
contribution, we show how such extensions are instrumental in the setting of
discrete quantum gravity, towards providing a covariant statistical framework
for the emergence of continuum spacetime. We discuss the significant role
played by information-theoretic characterizations of equilibrium. We present
the Gibbs state description of the geometry of a tetrahedron and its
quantization, thereby providing a statistical description of the characterizing
quanta of space in quantum gravity. We use field coherent states for a
generalized Gibbs state to write an effective statistical field theory that
perturbatively generates 2-complexes, which are discrete spacetime histories in
several quantum gravity approaches.
|
[
{
"created": "Mon, 17 Jun 2019 16:28:47 GMT",
"version": "v1"
}
] |
2019-08-12
|
[
[
"Chirco",
"Goffredo",
""
],
[
"Kotecha",
"Isha",
""
]
] |
Maximum entropy principle and Souriau's symplectic generalization of Gibbs states have provided crucial insights leading to extensions of standard equilibrium statistical mechanics and thermodynamics. In this brief contribution, we show how such extensions are instrumental in the setting of discrete quantum gravity, towards providing a covariant statistical framework for the emergence of continuum spacetime. We discuss the significant role played by information-theoretic characterizations of equilibrium. We present the Gibbs state description of the geometry of a tetrahedron and its quantization, thereby providing a statistical description of the characterizing quanta of space in quantum gravity. We use field coherent states for a generalized Gibbs state to write an effective statistical field theory that perturbatively generates 2-complexes, which are discrete spacetime histories in several quantum gravity approaches.
|
2205.05674
|
Alejandro Jim\'enez-Cano
|
Alejandro Jim\'enez-Cano and Francisco Jos\'e Maldonado Torralba
|
Vector stability in quadratic metric-affine theories
|
23 pages, no figures, no tables. Some parts have been extended,
rewritten and clarified. Version accepted for publication in JCAP
| null |
10.1088/1475-7516/2022/09/044
| null |
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
In this work we study the stability of the four vector irreducible pieces of
the torsion and the nonmetricity tensors in the general quadratic metric-affine
Lagrangian in 4 dimensions. The goal will be to elucidate under which
conditions the spin-1 modes associated to such vectors can propagate in a safe
way, together with the graviton. This highly constrains the theory reducing the
parameter space of the quadratic curvature part from 16 to 5 parameters. We
also study the sub-case of Weyl-Cartan gravity, proving that the stability of
the vector sector is only compatible with an Einstein-Proca theory for the Weyl
vector.
|
[
{
"created": "Wed, 11 May 2022 17:58:14 GMT",
"version": "v1"
},
{
"created": "Fri, 29 Jul 2022 16:00:54 GMT",
"version": "v2"
}
] |
2022-09-21
|
[
[
"Jiménez-Cano",
"Alejandro",
""
],
[
"Torralba",
"Francisco José Maldonado",
""
]
] |
In this work we study the stability of the four vector irreducible pieces of the torsion and the nonmetricity tensors in the general quadratic metric-affine Lagrangian in 4 dimensions. The goal will be to elucidate under which conditions the spin-1 modes associated to such vectors can propagate in a safe way, together with the graviton. This highly constrains the theory reducing the parameter space of the quadratic curvature part from 16 to 5 parameters. We also study the sub-case of Weyl-Cartan gravity, proving that the stability of the vector sector is only compatible with an Einstein-Proca theory for the Weyl vector.
|
0808.3644
|
Iver Brevik
|
Iver Brevik
|
Two-Fluid Viscous Modified Gravity on a RS Brane
|
8 pages, no figures; to appear in Gravitation & Cosmology
|
Grav.Cosmol.14:332-335,2008
|
10.1134/S0202289308040075
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Singularities in the dark energy late universe are discussed, under the
assumption that the Lagrangian contains the Einstein term R plus a modified
gravity term R^\alpha, where \alpha is a constant. The 4D fluid is taken to be
viscous and composed of two components, one Einstein component where the bulk
viscosity is proportional to the scalar expansion \theta, and another modified
component where the bulk viscosity is proportional to the power
\theta^{2\alpha-1}. Under these conditions it is known from earlier that the
bulk viscosity can drive the fluid from the quintessence region (w > -1) into
the phantom region (w<-1), where w is the thermodynamical parameter [I. Brevik,
Gen. Rel. Grav. 38, 1317 (2006)]. We combine this 4D theory with the 5D
Randall-Sundrum II theory in which there is a single spatially flat brane
situated at y=0. We find that the Big Rip singularity, which occurs in 4D
theory if \alpha >1/2, carries over to the 5D metric in the bulk, |y|>0. The
present investigation generalizes that of an earlier paper [I. Brevik,
arXiv:0807.1797; to appear in Eur. Phys. J. C] in which only a one-component
modified fluid was present.
|
[
{
"created": "Wed, 27 Aug 2008 07:55:19 GMT",
"version": "v1"
}
] |
2008-12-18
|
[
[
"Brevik",
"Iver",
""
]
] |
Singularities in the dark energy late universe are discussed, under the assumption that the Lagrangian contains the Einstein term R plus a modified gravity term R^\alpha, where \alpha is a constant. The 4D fluid is taken to be viscous and composed of two components, one Einstein component where the bulk viscosity is proportional to the scalar expansion \theta, and another modified component where the bulk viscosity is proportional to the power \theta^{2\alpha-1}. Under these conditions it is known from earlier that the bulk viscosity can drive the fluid from the quintessence region (w > -1) into the phantom region (w<-1), where w is the thermodynamical parameter [I. Brevik, Gen. Rel. Grav. 38, 1317 (2006)]. We combine this 4D theory with the 5D Randall-Sundrum II theory in which there is a single spatially flat brane situated at y=0. We find that the Big Rip singularity, which occurs in 4D theory if \alpha >1/2, carries over to the 5D metric in the bulk, |y|>0. The present investigation generalizes that of an earlier paper [I. Brevik, arXiv:0807.1797; to appear in Eur. Phys. J. C] in which only a one-component modified fluid was present.
|
1211.2702
|
Daniele Pranzetti
|
Daniele Pranzetti
|
Dynamical evaporation of quantum horizons
|
35 pages, 5 figures; improved and more detailed presentation;
published in CQG
|
2013 Class. Quantum Grav. 30 165004
|
10.1088/0264-9381/30/16/165004
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We describe the black hole evaporation process driven by the dynamical
evolution of the quantum gravitational degrees of freedom resident at the
horizon, as identified by the loop quantum gravity kinematics. Using a parallel
with the Brownian motion, we interpret the first law of quantum dynamical
horizon in terms of a fluctuation-dissipation relation. In this way, the
horizon evolution is described in terms of relaxation to an equilibrium state
balanced by the excitation of Planck scale constituents of the horizon. This
discrete quantum hair structure associated to the horizon geometry produces a
deviation from thermality in the radiation spectrum. We investigate the final
stage of the evaporation process and show how the dynamics leads to the
formation of a massive remnant, which can eventually decay. Implications for
the information paradox are discussed.
|
[
{
"created": "Mon, 12 Nov 2012 17:23:44 GMT",
"version": "v1"
},
{
"created": "Mon, 15 Jul 2013 16:12:18 GMT",
"version": "v2"
}
] |
2013-07-16
|
[
[
"Pranzetti",
"Daniele",
""
]
] |
We describe the black hole evaporation process driven by the dynamical evolution of the quantum gravitational degrees of freedom resident at the horizon, as identified by the loop quantum gravity kinematics. Using a parallel with the Brownian motion, we interpret the first law of quantum dynamical horizon in terms of a fluctuation-dissipation relation. In this way, the horizon evolution is described in terms of relaxation to an equilibrium state balanced by the excitation of Planck scale constituents of the horizon. This discrete quantum hair structure associated to the horizon geometry produces a deviation from thermality in the radiation spectrum. We investigate the final stage of the evaporation process and show how the dynamics leads to the formation of a massive remnant, which can eventually decay. Implications for the information paradox are discussed.
|
gr-qc/0507095
|
Michel Leclerc
|
M. Leclerc
|
One-parameter teleparallel limit of Poincare gravity
|
8 pages, revtex4, accepted for publication in Phys. Rev. D
|
Phys.Rev. D72 (2005) 044002
|
10.1103/PhysRevD.72.044002
| null |
gr-qc
| null |
Poincare gauge theories that, in the absence of spinning matter, reduce to
the one-parameter teleparallel theory are investigated with respect to their
mathematical consistency and experimental viability. It is argued that the
theories can be consistently coupled to the known standard model particles.
Moreover, we establish the result that in the classical limit, such theories
share a large class of solutions with general relativity, containing, among
others, the four classical black hole solutions (Schwarzschild,
Reisner-Nordstrom, Kerr and Kerr-Newman), as well as the complete class of
Friedman-Robertson-Walker cosmological solutions, thereby extending older
viability results that were restricted to the correct Newtonian limit and to
the existence of the Schwarzschild solution.
|
[
{
"created": "Fri, 22 Jul 2005 22:16:42 GMT",
"version": "v1"
}
] |
2009-11-11
|
[
[
"Leclerc",
"M.",
""
]
] |
Poincare gauge theories that, in the absence of spinning matter, reduce to the one-parameter teleparallel theory are investigated with respect to their mathematical consistency and experimental viability. It is argued that the theories can be consistently coupled to the known standard model particles. Moreover, we establish the result that in the classical limit, such theories share a large class of solutions with general relativity, containing, among others, the four classical black hole solutions (Schwarzschild, Reisner-Nordstrom, Kerr and Kerr-Newman), as well as the complete class of Friedman-Robertson-Walker cosmological solutions, thereby extending older viability results that were restricted to the correct Newtonian limit and to the existence of the Schwarzschild solution.
|
gr-qc/0509004
|
Yaakov Friedman
|
Yaakov Friedman and Yuriy Gofman
|
A new relativistic kinematics of accelerated systems
|
12 pages, 2 figures
|
Physica Scripta82:015004, 2010
|
10.1088/0031-8949/82/01/015004
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We consider transformations between uniformly accelerated systems, assuming
that the Clock Hypothesis is false. We use the proper velocity-time description
of events rather than the usual space-time description in order to obtain
linear transformations. Based on the generalized principle of relativity and
the ensuing symmetry, we obtain transformations of Lorentz-type. We predict the
existence of a maximal acceleration and time dilation due to acceleration. We
also predict a Doppler shift due to acceleration of the source in addition to
the shift due to the source's velocity. Based on our results, we explain the W.
K\"{u}ndig experiment, as reanalyzed by Kholmetski \textit{et al}, and obtain
an estimate of the maximal acceleration.
|
[
{
"created": "Thu, 1 Sep 2005 11:48:21 GMT",
"version": "v1"
},
{
"created": "Tue, 22 Jun 2010 11:55:07 GMT",
"version": "v2"
}
] |
2015-06-25
|
[
[
"Friedman",
"Yaakov",
""
],
[
"Gofman",
"Yuriy",
""
]
] |
We consider transformations between uniformly accelerated systems, assuming that the Clock Hypothesis is false. We use the proper velocity-time description of events rather than the usual space-time description in order to obtain linear transformations. Based on the generalized principle of relativity and the ensuing symmetry, we obtain transformations of Lorentz-type. We predict the existence of a maximal acceleration and time dilation due to acceleration. We also predict a Doppler shift due to acceleration of the source in addition to the shift due to the source's velocity. Based on our results, we explain the W. K\"{u}ndig experiment, as reanalyzed by Kholmetski \textit{et al}, and obtain an estimate of the maximal acceleration.
|
1308.0581
|
Artyom Astashenok V
|
Artyom V. Astashenok
|
Effective Dark Energy Models and Dark Energy Models with Bounce in
frames of $F(T)$ Gravity
|
10 pp., 5 figures
| null |
10.1007/s10509-014-1846-6
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Various cosmological models in frames of $F(T)$ gravity are considered. The
general scheme of constructing effective dark energy models with various
evolution is presented. It is showed that these models in principle are
compatible with $\Lambda$CDM model. The dynamics of universe governed by $F(T)$
gravity can mimics $\Lambda$CDM evolution in past but declines from it in a
future. We also construct some dark energy models with the "real"
(non-effective) equation-of-state parameter $w$ such that $w\leq-1$. It is
showed that in $F(T)$ gravity the Universe filled phantom field not necessarily
ends its existence in singularity. There are two possible mechanisms permitting
the final singularity. Firstly due to the nonlinear dependence between energy
density and $H^{2}$ ($H$ is the Hubble parameter) the universe can expands not
so fast as in the general relativity and in fact Little Rip regime take place
instead Big Rip. We also considered the models with possible bounce in future.
In these models the universe expansion can mimics the dynamics with future
singularity but due to bounce in future universe begin contracts.
|
[
{
"created": "Fri, 2 Aug 2013 19:00:56 GMT",
"version": "v1"
},
{
"created": "Mon, 5 Aug 2013 10:53:50 GMT",
"version": "v2"
},
{
"created": "Tue, 6 Aug 2013 10:51:41 GMT",
"version": "v3"
}
] |
2015-06-16
|
[
[
"Astashenok",
"Artyom V.",
""
]
] |
Various cosmological models in frames of $F(T)$ gravity are considered. The general scheme of constructing effective dark energy models with various evolution is presented. It is showed that these models in principle are compatible with $\Lambda$CDM model. The dynamics of universe governed by $F(T)$ gravity can mimics $\Lambda$CDM evolution in past but declines from it in a future. We also construct some dark energy models with the "real" (non-effective) equation-of-state parameter $w$ such that $w\leq-1$. It is showed that in $F(T)$ gravity the Universe filled phantom field not necessarily ends its existence in singularity. There are two possible mechanisms permitting the final singularity. Firstly due to the nonlinear dependence between energy density and $H^{2}$ ($H$ is the Hubble parameter) the universe can expands not so fast as in the general relativity and in fact Little Rip regime take place instead Big Rip. We also considered the models with possible bounce in future. In these models the universe expansion can mimics the dynamics with future singularity but due to bounce in future universe begin contracts.
|
gr-qc/9303024
| null |
Frederick J. Ernst and Isidore Hauser
|
Generalized Symmetries of the Einstein Equations
|
22 pages, LaTeX document, report FJE-93-002
| null |
10.1063/1.530302
| null |
gr-qc
| null |
We reformulate the symmetries of Gurses [Phys. Rev. Lett. 70, 367 (1993)] in
a more abstract, more geometrical manner. The type (b) transformation of
\gurses\ is related to a diffeomorphism of the differentiable manifold onto
itself. The type (c) symmetry is replaced by a more general type (c-bar)
symmetry that has the nice property that the commutator of a type (c-bar)
generator with a type (a) generator is itself of type (c-bar). We identify a
differential constraint that transformations of type (c) and (c-bar) must
satisfy, and which, in our opinion, may severely limit the usefulness of these
transformations.
|
[
{
"created": "Sat, 20 Mar 1993 00:34:59 GMT",
"version": "v1"
}
] |
2009-10-22
|
[
[
"Ernst",
"Frederick J.",
""
],
[
"Hauser",
"Isidore",
""
]
] |
We reformulate the symmetries of Gurses [Phys. Rev. Lett. 70, 367 (1993)] in a more abstract, more geometrical manner. The type (b) transformation of \gurses\ is related to a diffeomorphism of the differentiable manifold onto itself. The type (c) symmetry is replaced by a more general type (c-bar) symmetry that has the nice property that the commutator of a type (c-bar) generator with a type (a) generator is itself of type (c-bar). We identify a differential constraint that transformations of type (c) and (c-bar) must satisfy, and which, in our opinion, may severely limit the usefulness of these transformations.
|
2102.05495
|
Genly Le\'on
|
Genly Leon, Sebasti\'an Cu\'ellar, Esteban Gonz\'alez, Samuel Lepe,
Claudio Michea and Alfredo D. Millano
|
Averaging Generalized Scalar Field Cosmologies II: Locally Rotationally
Symmetric Bianchi I and flat Friedmann-Lema\^itre-Robertson-Walker models
|
Research Program Averaging Generalized Scalar Field Cosmologies, part
II. 27 pages, 7 compound figures. Minor revision. References updated.
Discussion improved
| null |
10.1140/epjc/s10052-021-09230-5
| null |
gr-qc math-ph math.MP
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Scalar field cosmologies with a generalized harmonic potential and a matter
fluid with a barotropic Equation of State (EoS) with barotropic index $\gamma$
for the Locally Rotationally Symmetric (LRS) Bianchi I and flat
Friedmann-Lema\^itre-Robertson-Walker (FLRW) metrics are investigated. Methods
from the theory of averaging of nonlinear dynamical systems are used to prove
that time-dependent systems and their corresponding time-averaged versions have
the same late-time dynamics. Therefore, the simplest time-averaged system
determines the future asymptotic behavior. Depending on the values of $\gamma$,
the late-time attractors of physical interests are flat quintessence dominated
FLRW universe and Einstein-de Sitter solution. With this approach, the
oscillations entering the system through the Klein-Gordon (KG) equation can be
controlled and smoothed out as the Hubble parameter $H$ - acting as
time-dependent perturbation parameter - tends monotonically to zero. Numerical
simulations are presented as evidence of such behavior.
|
[
{
"created": "Wed, 10 Feb 2021 15:35:17 GMT",
"version": "v1"
},
{
"created": "Thu, 11 Feb 2021 23:23:15 GMT",
"version": "v2"
},
{
"created": "Wed, 31 Mar 2021 03:55:41 GMT",
"version": "v3"
},
{
"created": "Tue, 27 Apr 2021 17:48:48 GMT",
"version": "v4"
}
] |
2021-06-03
|
[
[
"Leon",
"Genly",
""
],
[
"Cuéllar",
"Sebastián",
""
],
[
"González",
"Esteban",
""
],
[
"Lepe",
"Samuel",
""
],
[
"Michea",
"Claudio",
""
],
[
"Millano",
"Alfredo D.",
""
]
] |
Scalar field cosmologies with a generalized harmonic potential and a matter fluid with a barotropic Equation of State (EoS) with barotropic index $\gamma$ for the Locally Rotationally Symmetric (LRS) Bianchi I and flat Friedmann-Lema\^itre-Robertson-Walker (FLRW) metrics are investigated. Methods from the theory of averaging of nonlinear dynamical systems are used to prove that time-dependent systems and their corresponding time-averaged versions have the same late-time dynamics. Therefore, the simplest time-averaged system determines the future asymptotic behavior. Depending on the values of $\gamma$, the late-time attractors of physical interests are flat quintessence dominated FLRW universe and Einstein-de Sitter solution. With this approach, the oscillations entering the system through the Klein-Gordon (KG) equation can be controlled and smoothed out as the Hubble parameter $H$ - acting as time-dependent perturbation parameter - tends monotonically to zero. Numerical simulations are presented as evidence of such behavior.
|
1308.0024
|
Tirthabir Biswas
|
Tirthabir Biswas
|
Before the Bang
|
Essay, received "Honorable Mention" in the GRF 2013 "Essays on
Gravitation" competition
| null |
10.1142/S0218271813420315
| null |
gr-qc astro-ph.CO hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
While inflation has been an extremely successful cosmological paradigm,
almost certainly something have had to have happened before it began. Can the
pre-inflationary phase be of any theoretical or phenomenological significance?
Could Quantum Gravity have played any interesting role in this story? These are
some of the questions we want to explore in this essay written for the Gravity
Research Foundation 2013 "Awards for Essays on Gravitation" competition.
|
[
{
"created": "Wed, 31 Jul 2013 20:07:16 GMT",
"version": "v1"
}
] |
2015-06-16
|
[
[
"Biswas",
"Tirthabir",
""
]
] |
While inflation has been an extremely successful cosmological paradigm, almost certainly something have had to have happened before it began. Can the pre-inflationary phase be of any theoretical or phenomenological significance? Could Quantum Gravity have played any interesting role in this story? These are some of the questions we want to explore in this essay written for the Gravity Research Foundation 2013 "Awards for Essays on Gravitation" competition.
|
1811.05179
|
Tomohiro Harada
|
Tomohiro Harada, Vitor Cardoso, Daiki Miyata
|
Particle creation in gravitational collapse to a horizonless compact
object
|
30 pages, 6 figures, typos corrected, minor correction
|
Phys. Rev. D 99, 044039 (2019)
|
10.1103/PhysRevD.99.044039
|
RUP-18-34
|
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Black holes (BHs) play a central role in physics. However, gathering
observational evidence for their existence is a notoriously difficult task.
Current strategies to quantify the evidence for BHs all boil down to looking
for signs of highly compact, horizonless bodies. Here, we study particle
creation by objects which collapse to form ultra-compact configurations, with
surface at an areal radius $R=R_{f}$ satisfying $1-(2M/R_{f})= \epsilon^{2}\ll
1$ with $M$ the object mass. We assume that gravitational collapse proceeds in
a `standard' manner until $R=R_{f}+2M \epsilon^{2\beta}$, where $\beta>0$, and
then slows down to form a static object of radius $R_{f}$. In the standard
collapsing phase, Hawking-like thermal radiation is emitted, which is as strong
as the Hawking radiation of a BH with the same mass but lasts only for $\sim
40~(M/M_{\odot})[44+\ln (10^{-19}/\epsilon)]~\mu \mbox{s}$. Thereafter, in a
very large class of models, there exist two bursts of radiation separated by a
very long dormant stage. The first burst occurs at the end of the transient
Hawking radiation, and is followed by a quiescent stage which lasts for $\sim
6\times 10^{6}~(\epsilon/10^{-19})^{-1}(M/M_{\odot})~\mbox{yr}$. Afterwards,
the second burst is triggered, after which there is no more particle production
and the star is forever dark. In a model with $\beta=1$, both the first and
second bursts outpower the transient Hawking radiation by a factor $\sim
10^{38}(\epsilon/10^{-19})^{-2}$.
|
[
{
"created": "Tue, 13 Nov 2018 09:40:52 GMT",
"version": "v1"
},
{
"created": "Fri, 23 Nov 2018 06:48:53 GMT",
"version": "v2"
},
{
"created": "Thu, 28 Feb 2019 05:18:51 GMT",
"version": "v3"
}
] |
2019-03-01
|
[
[
"Harada",
"Tomohiro",
""
],
[
"Cardoso",
"Vitor",
""
],
[
"Miyata",
"Daiki",
""
]
] |
Black holes (BHs) play a central role in physics. However, gathering observational evidence for their existence is a notoriously difficult task. Current strategies to quantify the evidence for BHs all boil down to looking for signs of highly compact, horizonless bodies. Here, we study particle creation by objects which collapse to form ultra-compact configurations, with surface at an areal radius $R=R_{f}$ satisfying $1-(2M/R_{f})= \epsilon^{2}\ll 1$ with $M$ the object mass. We assume that gravitational collapse proceeds in a `standard' manner until $R=R_{f}+2M \epsilon^{2\beta}$, where $\beta>0$, and then slows down to form a static object of radius $R_{f}$. In the standard collapsing phase, Hawking-like thermal radiation is emitted, which is as strong as the Hawking radiation of a BH with the same mass but lasts only for $\sim 40~(M/M_{\odot})[44+\ln (10^{-19}/\epsilon)]~\mu \mbox{s}$. Thereafter, in a very large class of models, there exist two bursts of radiation separated by a very long dormant stage. The first burst occurs at the end of the transient Hawking radiation, and is followed by a quiescent stage which lasts for $\sim 6\times 10^{6}~(\epsilon/10^{-19})^{-1}(M/M_{\odot})~\mbox{yr}$. Afterwards, the second burst is triggered, after which there is no more particle production and the star is forever dark. In a model with $\beta=1$, both the first and second bursts outpower the transient Hawking radiation by a factor $\sim 10^{38}(\epsilon/10^{-19})^{-2}$.
|
gr-qc/0504138
|
Ali Shojai
|
F. Shojai, A. Shirinifard
|
Classical and Quantum Limits in Bohmian Quantum Cosmology
|
to appear in Int. J. Mod. Phys. D
|
Int.J.Mod.Phys. D14 (2005) 1333
|
10.1142/S0218271805007140
| null |
gr-qc quant-ph
| null |
In this paper we have investigated the classical limit in Bohmian quantum
cosmology. It is observed that in the quantum regime where the quantum
potential is greater than the classical one, one has an expansion in terms of
negative powers of the Planck constant. But in the classical limit there are
regions having positive powers of the Planck constant, and regions having
negative powers and also regions having both. The conclusion is that the
Bohmian classical limit cannot be obtained by letting the Planck constant goes
to zero.
|
[
{
"created": "Thu, 28 Apr 2005 07:59:22 GMT",
"version": "v1"
}
] |
2009-11-11
|
[
[
"Shojai",
"F.",
""
],
[
"Shirinifard",
"A.",
""
]
] |
In this paper we have investigated the classical limit in Bohmian quantum cosmology. It is observed that in the quantum regime where the quantum potential is greater than the classical one, one has an expansion in terms of negative powers of the Planck constant. But in the classical limit there are regions having positive powers of the Planck constant, and regions having negative powers and also regions having both. The conclusion is that the Bohmian classical limit cannot be obtained by letting the Planck constant goes to zero.
|
2103.17053
|
Sugumi Kanno
|
Sugumi Kanno, Jiro Soda, Junsei Tokuda
|
Indirect detection of gravitons through quantum entanglement
|
5 pages, 2 figures
|
Phys. Rev. D 104, 083516 (2021)
|
10.1103/PhysRevD.104.083516
|
KOBE-COSMO-21-06
|
gr-qc hep-ph hep-th quant-ph
|
http://creativecommons.org/licenses/by/4.0/
|
We propose an experiment that the entanglement between two macroscopic
mirrors suspended at the end of an equal-arm interferometer is destroyed by the
noise of gravitons through bremsstrahlung. By calculating the correlation
function of the noise, we obtain the decoherence time from the decoherence
functional. We estimate that the decoherence time induced by the noise of
gravitons in squeezed states stemming from inflation is approximately 20
seconds for 40 km long arms and 40 kg mirrors. Our analysis shows that
observation of the decoherence time of quantum entanglement has the potential
to detect gravitons indirectly. This indirect detection of gravitons would give
strong evidence of quantum gravity.
|
[
{
"created": "Tue, 30 Mar 2021 14:14:47 GMT",
"version": "v1"
}
] |
2021-10-13
|
[
[
"Kanno",
"Sugumi",
""
],
[
"Soda",
"Jiro",
""
],
[
"Tokuda",
"Junsei",
""
]
] |
We propose an experiment that the entanglement between two macroscopic mirrors suspended at the end of an equal-arm interferometer is destroyed by the noise of gravitons through bremsstrahlung. By calculating the correlation function of the noise, we obtain the decoherence time from the decoherence functional. We estimate that the decoherence time induced by the noise of gravitons in squeezed states stemming from inflation is approximately 20 seconds for 40 km long arms and 40 kg mirrors. Our analysis shows that observation of the decoherence time of quantum entanglement has the potential to detect gravitons indirectly. This indirect detection of gravitons would give strong evidence of quantum gravity.
|
0810.3809
|
Sunil Maharaj
|
S. Thirukkanesh, S. D. Maharaj
|
Charged anisotropic matter with linear equation of state
|
17 pages, To appear in Class. Quantum Grav
|
Class.Quant.Grav.25:235001,2008
|
10.1088/0264-9381/25/23/235001
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We consider the general situation of a compact relativistic body with
anisotropic pressures in the presence of the electromagnetic field. The
equation of state for the matter distribution is linear and may be applied to
strange stars with quark matter. Three classes of new exact solutions are found
to the Einstein-Maxwell system. This is achieved by specifying a particular
form for one of the gravitational potentials and the electric field intensity.
We can regain anisotropic and isotropic models from our general class of
solution. A physical analysis indicates that the charged solutions describe
realistic compact spheres with anisotropic matter distribution. The equation of
state is consistent with dark energy stars and charged quark matter
distributions. The masses and central densities correspond to realistic stellar
objects in the general case when anisotropy and charge are present.
|
[
{
"created": "Tue, 21 Oct 2008 12:07:55 GMT",
"version": "v1"
}
] |
2009-01-16
|
[
[
"Thirukkanesh",
"S.",
""
],
[
"Maharaj",
"S. D.",
""
]
] |
We consider the general situation of a compact relativistic body with anisotropic pressures in the presence of the electromagnetic field. The equation of state for the matter distribution is linear and may be applied to strange stars with quark matter. Three classes of new exact solutions are found to the Einstein-Maxwell system. This is achieved by specifying a particular form for one of the gravitational potentials and the electric field intensity. We can regain anisotropic and isotropic models from our general class of solution. A physical analysis indicates that the charged solutions describe realistic compact spheres with anisotropic matter distribution. The equation of state is consistent with dark energy stars and charged quark matter distributions. The masses and central densities correspond to realistic stellar objects in the general case when anisotropy and charge are present.
|
1401.0939
|
Ian Harry
|
The LIGO Scientific Collaboration, the Virgo Collaboration and the
NINJA-2 Collaboration: J. Aasi, B. P. Abbott, R. Abbott, T. Abbott, M. R.
Abernathy, T. Accadia, F. Acernese, K. Ackley, C. Adams, T. Adams, P.
Addesso, R. X. Adhikari, C. Affeldt, M. Agathos, N. Aggarwal, O. D. Aguiar,
A. Ain, P. Ajith, A. Alemic, B. Allen, A. Allocca, D. Amariutei, M. Andersen,
R. Anderson, S. B. Anderson, W. G. Anderson, K. Arai, M. C. Araya, C.
Arceneaux, J. Areeda, S. M. Aston, P. Astone, P. Aufmuth, C. Aulbert, L.
Austin, B. E. Aylott, S. Babak, P. T. Baker, G. Ballardin, S. W. Ballmer, J.
C. Barayoga, M. Barbet, B. C. Barish, D. Barker, F. Barone, B. Barr, L.
Barsotti, M. Barsuglia, M. A. Barton, I. Bartos, R. Bassiri, A. Basti, J. C.
Batch, J. Bauchrowitz, Th. S. Bauer, B. Behnke, M. Bejger, M. G. Beker, C.
Belczynski, A. S. Bell, C. Bell, G. Bergmann, D. Bersanetti, A. Bertolini, J.
Betzwieser, P. T. Beyersdorf, I. A. Bilenko, G. Billingsley, J. Birch, S.
Biscans, M. Bitossi, M. A. Bizouard, E. Black, J. K. Blackburn, L. Blackburn,
D. Blair, S. Bloemen, M. Blom, O. Bock, T. P. Bodiya, M. Boer, G. Bogaert, C.
Bogan, C. Bond, F. Bondu, L. Bonelli, R. Bonnand, R. Bork, M. Born, V.
Boschi, Sukanta Bose, L. Bosi, C. Bradaschia, P. R. Brady, V. B. Braginsky,
M. Branchesi, J. E. Brau, T. Briant, D. O. Bridges, A. Brillet, M. Brinkmann,
V. Brisson, A. F. Brooks, D. A. Brown, D. D. Brown, F. Br\"uckner, S.
Buchman, T. Bulik, H. J. Bulten, A. Buonanno, R. Burman, D. Buskulic, C. Buy,
L. Cadonati, G. Cagnoli, J. Calder\'on Bustillo, E. Calloni, J. B. Camp, P.
Campsie, K. C. Cannon, B. Canuel, J. Cao, C. D. Capano, F. Carbognani, L.
Carbone, S. Caride, A. Castiglia, S. Caudill, M. Cavagli\`a, F. Cavalier, R.
Cavalieri, C. Celerier, G. Cella, C. Cepeda, E. Cesarini, R. Chakraborty, T.
Chalermsongsak, S. J. Chamberlin, S. Chao, P. Charlton, E. Chassande-Mottin,
X. Chen, Y. Chen, A. Chincarini, A. Chiummo, H. S. Cho, J. Chow, N.
Christensen, Q. Chu, S. S. Y. Chua, S. Chung, G. Ciani, F. Clara, J. A.
Clark, F. Cleva, E. Coccia, P.-F. Cohadon, A. Colla, C. Collette, M.
Colombini, L. Cominsky, M. Constancio Jr., A. Conte, D. Cook, T. R. Corbitt,
M. Cordier, N. Cornish, A. Corpuz, A. Corsi, C. A. Costa, M. W. Coughlin, S.
Coughlin, J.-P. Coulon, S. Countryman, P. Couvares, D. M. Coward, M. Cowart,
D. C. Coyne, R. Coyne, K. Craig, J. D. E. Creighton, S. G. Crowder, A.
Cumming, L. Cunningham, E. Cuoco, K. Dahl, T. Dal Canton, M. Damjanic, S. L.
Danilishin, S. D'Antonio, K. Danzmann, V. Dattilo, H. Daveloza, M. Davier, G.
S. Davies, E. J. Daw, R. Day, T. Dayanga, G. Debreczeni, J. Degallaix, S.
Del\'eglise, W. Del Pozzo, T. Denker, T. Dent, H. Dereli, V. Dergachev, R. De
Rosa, R. T. DeRosa, R. DeSalvo, S. Dhurandhar, M. D\'iaz, L. Di Fiore, A. Di
Lieto, I. Di Palma, A. Di Virgilio, A. Donath, F. Donovan, K. L. Dooley, S.
Doravari, S. Dossa, R. Douglas, T. P. Downes, M. Drago, R. W. P. Drever, J.
C. Driggers, Z. Du, S. Dwyer, T. Eberle, T. Edo, M. Edwards, A. Effler, H.
Eggenstein, P. Ehrens, J. Eichholz, S. S. Eikenberry, G. Endr\H{o}czi, R.
Essick, T. Etzel, M. Evans, T. Evans, M. Factourovich, V. Fafone, S.
Fairhurst, Q. Fang, S. Farinon, B. Farr, W. M. Farr, M. Favata, H. Fehrmann,
M. M. Fejer, D. Feldbaum, F. Feroz, I. Ferrante, F. Ferrini, F. Fidecaro, L.
S. Finn, I. Fiori, R. P. Fisher, R. Flaminio, J.-D. Fournier, S. Franco, S.
Frasca, F. Frasconi, M. Frede, Z. Frei, A. Freise, R. Frey, T. T. Fricke, P.
Fritschel, V. V. Frolov, P. Fulda, M. Fyffe, J. Gair, L. Gammaitoni, S.
Gaonkar, F. Garufi, N. Gehrels, G. Gemme, E. Genin, A. Gennai, S. Ghosh, J.
A. Giaime, K. D. Giardina, A. Giazotto, C. Gill, J. Gleason, E. Goetz, R.
Goetz, L. Gondan, G. Gonz\'alez, N. Gordon, M. L. Gorodetsky, S. Gossan, S.
Go{\ss}ler, R. Gouaty, C. Gr\"af, P. B. Graff, M. Granata, A. Grant, S. Gras,
C. Gray, R. J. S. Greenhalgh, A. M. Gretarsson, P. Groot, H. Grote, K.
Grover, S. Grunewald, G. M. Guidi, C. Guido, K. Gushwa, E. K. Gustafson, R.
Gustafson, D. Hammer, G. Hammond, M. Hanke, J. Hanks, C. Hanna, J. Hanson, J.
Harms, G. M. Harry, I. W. Harry, E. D. Harstad, M. Hart, M. T. Hartman, C.-J.
Haster, K. Haughian, A. Heidmann, M. Heintze, H. Heitmann, P. Hello, G.
Hemming, M. Hendry, I. S. Heng, A. W. Heptonstall, M. Heurs, M. Hewitson, S.
Hild, D. Hoak, K. A. Hodge, K. Holt, S. Hooper, P. Hopkins, D. J. Hosken, J.
Hough, E. J. Howell, Y. Hu, B. Hughey, S. Husa, S. H. Huttner, M. Huynh, T.
Huynh-Dinh, D. R. Ingram, R. Inta, T. Isogai, A. Ivanov, B. R. Iyer, K.
Izumi, M. Jacobson, E. James, H. Jang, P. Jaranowski, Y. Ji, F.
Jim\'enez-Forteza, W. W. Johnson, D. I. Jones, R. Jones, R.J.G. Jonker, L.
Ju, Haris K, P. Kalmus, V. Kalogera, S. Kandhasamy, G. Kang, J. B. Kanner, J.
Karlen, M. Kasprzack, E. Katsavounidis, W. Katzman, H. Kaufer, K. Kawabe, F.
Kawazoe, F. K\'ef\'elian, G. M. Keiser, D. Keitel, D. B. Kelley, W. Kells, A.
Khalaidovski, F. Y. Khalili, E. A. Khazanov, C. Kim, K. Kim, N. Kim, N. G.
Kim, Y.-M. Kim, E. J. King, P. J. King, D. L. Kinzel, J. S. Kissel, S.
Klimenko, J. Kline, S. Koehlenbeck, K. Kokeyama, V. Kondrashov, S. Koranda,
W. Z. Korth, I. Kowalska, D. B. Kozak, A. Kremin, V. Kringel, B. Krishnan, A.
Kr\'olak, G. Kuehn, A. Kumar, P. Kumar, R. Kumar, L. Kuo, A. Kutynia, P.
Kwee, M. Landry, B. Lantz, S. Larson, P. D. Lasky, C. Lawrie, A. Lazzarini,
C. Lazzaro, P. Leaci, S. Leavey, E. O. Lebigot, C.-H. Lee, H. K. Lee, H. M.
Lee, J. Lee, M. Leonardi, J. R. Leong, A. Le Roux, N. Leroy, N. Letendre, Y.
Levin, B. Levine, J. Lewis, T. G. F. Li, K. Libbrecht, A. Libson, A. C. Lin,
T. B. Littenberg, V. Litvine, N. A. Lockerbie, V. Lockett, D. Lodhia, K.
Loew, J. Logue, A. L. Lombardi, M. Lorenzini, V. Loriette, M. Lormand, G.
Losurdo, J. Lough, M. J. Lubinski, H. L\"uck, E. Luijten, A. P. Lundgren, R.
Lynch, Y. Ma, J. Macarthur, E. P. Macdonald, T. MacDonald, B. Machenschalk,
M. MacInnis, D. M. Macleod, F. Magana-Sandoval, M. Mageswaran, C. Maglione,
K. Mailand, E. Majorana, I. Maksimovic, V. Malvezzi, N. Man, G. M. Manca, I.
Mandel, V. Mandic, V. Mangano, N. Mangini, M. Mantovani, F. Marchesoni, F.
Marion, S. M\'arka, Z. M\'arka, A. Markosyan, E. Maros, J. Marque, F.
Martelli, I. W. Martin, R. M. Martin, L. Martinelli, D. Martynov, J. N. Marx,
K. Mason, A. Masserot, T. J. Massinger, F. Matichard, L. Matone, R. A.
Matzner, N. Mavalvala, N. Mazumder, G. Mazzolo, R. McCarthy, D. E.
McClelland, S. C. McGuire, G. McIntyre, J. McIver, K. McLin, D. Meacher, G.
D. Meadors, M. Mehmet, J. Meidam, M. Meinders, A. Melatos, G. Mendell, R. A.
Mercer, S. Meshkov, C. Messenger, P. Meyers, H. Miao, C. Michel, E. E.
Mikhailov, L. Milano, S. Milde, J. Miller, Y. Minenkov, C. M. F. Mingarelli,
C. Mishra, S. Mitra, V. P. Mitrofanov, G. Mitselmakher, R. Mittleman, B. Moe,
P. Moesta, M. Mohan, S. R. P. Mohapatra, D. Moraru, G. Moreno, N. Morgado, S.
R. Morriss, K. Mossavi, B. Mours, C. M. Mow-Lowry, C. L. Mueller, G. Mueller,
S. Mukherjee, A. Mullavey, J. Munch, D. Murphy, P. G. Murray, A. Mytidis, M.
F. Nagy, D. Nanda Kumar, I. Nardecchia, L. Naticchioni, R. K. Nayak, V.
Necula, G. Nelemans, I. Neri, M. Neri, G. Newton, T. Nguyen, A. Nitz, F.
Nocera, D. Nolting, M. E. N. Normandin, L. K. Nuttall, E. Ochsner, J. O'Dell,
E. Oelker, J. J. Oh, S. H. Oh, F. Ohme, P. Oppermann, B. O'Reilly, R.
O'Shaughnessy, C. Osthelder, D. J. Ottaway, R. S. Ottens, H. Overmier, B. J.
Owen, C. Padilla, A. Pai, O. Palashov, C. Palomba, H. Pan, Y. Pan, C. Pankow,
F. Paoletti, R. Paoletti, M. A. Papa, H. Paris, A. Pasqualetti, R.
Passaquieti, D. Passuello, M. Pedraza, S. Penn, A. Perreca, M. Phelps, M.
Pichot, M. Pickenpack, F. Piergiovanni, V. Pierro, L. Pinard, I. M. Pinto, M.
Pitkin, J. Poeld, R. Poggiani, A. Poteomkin, J. Powell, J. Prasad, S.
Premachandra, T. Prestegard, L. R. Price, M. Prijatelj, S. Privitera, G. A.
Prodi, L. Prokhorov, O. Puncken, M. Punturo, P. Puppo, J. Qin, V. Quetschke,
E. Quintero, G. Quiroga, R. Quitzow-James, F. J. Raab, D. S. Rabeling, I.
R\'acz, H. Radkins, P. Raffai, S. Raja, G. Rajalakshmi, M. Rakhmanov, C.
Ramet, K. Ramirez, P. Rapagnani, V. Raymond, V. Re, J. Read, C. M. Reed, T.
Regimbau, S. Reid, D. H. Reitze, E. Rhoades, F. Ricci, K. Riles, N. A.
Robertson, F. Robinet, A. Rocchi, M. Rodruck, L. Rolland, J. G. Rollins, R.
Romano, G. Romanov, J. H. Romie, D. Rosi\'nska, S. Rowan, A. R\"udiger, P.
Ruggi, K. Ryan, F. Salemi, L. Sammut, V. Sandberg, J. R. Sanders, V.
Sannibale, I. Santiago-Prieto, E. Saracco, B. Sassolas, B. S. Sathyaprakash,
P. R. Saulson, R. Savage, J. Scheuer, R. Schilling, R. Schnabel, R. M. S.
Schofield, E. Schreiber, D. Schuette, B. F. Schutz, J. Scott, S. M. Scott, D.
Sellers, A. S. Sengupta, D. Sentenac, V. Sequino, A. Sergeev, D. Shaddock, S.
Shah, M. S. Shahriar, M. Shaltev, B. Shapiro, P. Shawhan, D. H. Shoemaker, T.
L. Sidery, K. Siellez, X. Siemens, D. Sigg, D. Simakov, A. Singer, L. Singer,
R. Singh, A. M. Sintes, B. J. J. Slagmolen, J. Slutsky, J. R. Smith, M.
Smith, R. J. E. Smith, N. D. Smith-Lefebvre, E. J. Son, B. Sorazu, T.
Souradeep, L. Sperandio, A. Staley, J. Stebbins, J. Steinlechner, S.
Steinlechner, B. C. Stephens, S. Steplewski, S. Stevenson, R. Stone, D.
Stops, K. A. Strain, N. Straniero, S. Strigin, R. Sturani, A. L. Stuver, T.
Z. Summerscales, S. Susmithan, P. J. Sutton, B. Swinkels, M. Tacca, D.
Talukder, D. B. Tanner, S. P. Tarabrin, R. Taylor, A. P. M. ter Braack, M. P.
Thirugnanasambandam, M. Thomas, P. Thomas, K. A. Thorne, K. S. Thorne, E.
Thrane, V. Tiwari, K. V. Tokmakov, C. Tomlinson, A. Toncelli, M. Tonelli, O.
Torre, C. V. Torres, C. I. Torrie, F. Travasso, G. Traylor, M. Tse, D.
Ugolini, C. S. Unnikrishnan, A. L. Urban, K. Urbanek, H. Vahlbruch, G.
Vajente, G. Valdes, M. Vallisneri, J. F. J. van den Brand, C. Van Den Broeck,
S. van der Putten, M. V. van der Sluys, J. van Heijningen, A. A. van Veggel,
S. Vass, M. Vas\'uth, R. Vaulin, A. Vecchio, G. Vedovato, J. Veitch, P. J.
Veitch, K. Venkateswara, D. Verkindt, S. S. Verma, F. Vetrano, A. Vicer\'e,
R. Vincent-Finley, J.-Y. Vinet, S. Vitale, T. Vo, H. Vocca, C. Vorvick, W. D.
Vousden, S. P. Vyachanin, A. Wade, L. Wade, M. Wade, M. Walker, L. Wallace,
M. Wang, X. Wang, R. L. Ward, M. Was, B. Weaver, L.-W. Wei, M. Weinert, A. J.
Weinstein, R. Weiss, T. Welborn, L. Wen, P. Wessels, M. West, T. Westphal, K.
Wette, J. T. Whelan, S. E. Whitcomb, D. J. White, B. F. Whiting, K. Wiesner,
C. Wilkinson, K. Williams, L. Williams, R. Williams, T. Williams, A. R.
Williamson, J. L. Willis, B. Willke, M. Wimmer, W. Winkler, C. C. Wipf, A. G.
Wiseman, H. Wittel, G. Woan, J. Worden, J. Yablon, I. Yakushin, H. Yamamoto,
C. C. Yancey, H. Yang, Z. Yang, S. Yoshida, M. Yvert, A. Zadro\.zny, M.
Zanolin, J.-P. Zendri, Fan Zhang, L. Zhang, C. Zhao, X. J. Zhu, M. E. Zucker,
S. Zuraw, J. Zweizig, M. Boyle, B. Br\"ugmann, L. T. Buchman, M. Campanelli,
T. Chu, Z. B. Etienne, M. Hannam, J. Healy, I. Hinder, L. E. Kidder, P.
Laguna, Y. T. Liu, L. London, C. O. Lousto, G. Lovelace, I. MacDonald, P.
Marronetti, P. M\"osta, D. M\"uller, B. C. Mundim, H. Nakano, V. Paschalidis,
L. Pekowsky, D. Pollney, H. P. Pfeiffer, M. Ponce, M. P\"urrer, G.
Reifenberger, C. Reisswig, L. Santamar\'ia, M. A. Scheel, S. L. Shapiro, D.
Shoemaker, C. F. Sopuerta, U. Sperhake, B. Szil\'agyi, N. W. Taylor, W.
Tichy, P. Tsatsin, Y. Zlochower
|
The NINJA-2 project: Detecting and characterizing gravitational
waveforms modelled using numerical binary black hole simulations
|
52 pages, 11 figures, 7 tables
|
Class. Quantum Grav. 31 115004, 2014
|
10.1088/0264-9381/31/11/115004
|
LIGO-P1300199
|
gr-qc astro-ph.CO
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The Numerical INJection Analysis (NINJA) project is a collaborative effort
between members of the numerical relativity and gravitational-wave astrophysics
communities. The purpose of NINJA is to study the ability to detect
gravitational waves emitted from merging binary black holes and recover their
parameters with next-generation gravitational-wave observatories. We report
here on the results of the second NINJA project, NINJA-2, which employs 60
complete binary black hole hybrid waveforms consisting of a numerical portion
modelling the late inspiral, merger, and ringdown stitched to a post-Newtonian
portion modelling the early inspiral. In a "blind injection challenge" similar
to that conducted in recent LIGO and Virgo science runs, we added 7 hybrid
waveforms to two months of data recolored to predictions of Advanced LIGO and
Advanced Virgo sensitivity curves during their first observing runs. The
resulting data was analyzed by gravitational-wave detection algorithms and 6 of
the waveforms were recovered with false alarm rates smaller than 1 in a
thousand years. Parameter estimation algorithms were run on each of these
waveforms to explore the ability to constrain the masses, component angular
momenta and sky position of these waveforms. We also perform a large-scale
monte-carlo study to assess the ability to recover each of the 60 hybrid
waveforms with early Advanced LIGO and Advanced Virgo sensitivity curves. Our
results predict that early Advanced LIGO and Advanced Virgo will have a
volume-weighted average sensitive distance of 300Mpc (1Gpc) for
$10M_{\odot}+10M_{\odot}$ ($50M_{\odot}+50M_{\odot}$) binary black hole
coalescences. We demonstrate that neglecting the component angular momenta in
the waveform models used in matched-filtering will result in a reduction in
sensitivity for systems with large component angular momenta. [Abstract
abridged for ArXiv, full version in PDF]
|
[
{
"created": "Sun, 5 Jan 2014 21:00:19 GMT",
"version": "v1"
}
] |
2014-05-21
|
[
[
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"",
""
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[
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"van der Putten",
"S.",
""
],
[
"van der Sluys",
"M. V.",
""
],
[
"van Heijningen",
"J.",
""
],
[
"van Veggel",
"A. A.",
""
],
[
"Vass",
"S.",
""
],
[
"Vasúth",
"M.",
""
],
[
"Vaulin",
"R.",
""
],
[
"Vecchio",
"A.",
""
],
[
"Vedovato",
"G.",
""
],
[
"Veitch",
"J.",
""
],
[
"Veitch",
"P. J.",
""
],
[
"Venkateswara",
"K.",
""
],
[
"Verkindt",
"D.",
""
],
[
"Verma",
"S. S.",
""
],
[
"Vetrano",
"F.",
""
],
[
"Viceré",
"A.",
""
],
[
"Vincent-Finley",
"R.",
""
],
[
"Vinet",
"J. -Y.",
""
],
[
"Vitale",
"S.",
""
],
[
"Vo",
"T.",
""
],
[
"Vocca",
"H.",
""
],
[
"Vorvick",
"C.",
""
],
[
"Vousden",
"W. D.",
""
],
[
"Vyachanin",
"S. P.",
""
],
[
"Wade",
"A.",
""
],
[
"Wade",
"L.",
""
],
[
"Wade",
"M.",
""
],
[
"Walker",
"M.",
""
],
[
"Wallace",
"L.",
""
],
[
"Wang",
"M.",
""
],
[
"Wang",
"X.",
""
],
[
"Ward",
"R. L.",
""
],
[
"Was",
"M.",
""
],
[
"Weaver",
"B.",
""
],
[
"Wei",
"L. -W.",
""
],
[
"Weinert",
"M.",
""
],
[
"Weinstein",
"A. J.",
""
],
[
"Weiss",
"R.",
""
],
[
"Welborn",
"T.",
""
],
[
"Wen",
"L.",
""
],
[
"Wessels",
"P.",
""
],
[
"West",
"M.",
""
],
[
"Westphal",
"T.",
""
],
[
"Wette",
"K.",
""
],
[
"Whelan",
"J. T.",
""
],
[
"Whitcomb",
"S. E.",
""
],
[
"White",
"D. J.",
""
],
[
"Whiting",
"B. F.",
""
],
[
"Wiesner",
"K.",
""
],
[
"Wilkinson",
"C.",
""
],
[
"Williams",
"K.",
""
],
[
"Williams",
"L.",
""
],
[
"Williams",
"R.",
""
],
[
"Williams",
"T.",
""
],
[
"Williamson",
"A. R.",
""
],
[
"Willis",
"J. L.",
""
],
[
"Willke",
"B.",
""
],
[
"Wimmer",
"M.",
""
],
[
"Winkler",
"W.",
""
],
[
"Wipf",
"C. C.",
""
],
[
"Wiseman",
"A. G.",
""
],
[
"Wittel",
"H.",
""
],
[
"Woan",
"G.",
""
],
[
"Worden",
"J.",
""
],
[
"Yablon",
"J.",
""
],
[
"Yakushin",
"I.",
""
],
[
"Yamamoto",
"H.",
""
],
[
"Yancey",
"C. C.",
""
],
[
"Yang",
"H.",
""
],
[
"Yang",
"Z.",
""
],
[
"Yoshida",
"S.",
""
],
[
"Yvert",
"M.",
""
],
[
"Zadrożny",
"A.",
""
],
[
"Zanolin",
"M.",
""
],
[
"Zendri",
"J. -P.",
""
],
[
"Zhang",
"Fan",
""
],
[
"Zhang",
"L.",
""
],
[
"Zhao",
"C.",
""
],
[
"Zhu",
"X. J.",
""
],
[
"Zucker",
"M. E.",
""
],
[
"Zuraw",
"S.",
""
],
[
"Zweizig",
"J.",
""
],
[
"Boyle",
"M.",
""
],
[
"Brügmann",
"B.",
""
],
[
"Buchman",
"L. T.",
""
],
[
"Campanelli",
"M.",
""
],
[
"Chu",
"T.",
""
],
[
"Etienne",
"Z. B.",
""
],
[
"Hannam",
"M.",
""
],
[
"Healy",
"J.",
""
],
[
"Hinder",
"I.",
""
],
[
"Kidder",
"L. E.",
""
],
[
"Laguna",
"P.",
""
],
[
"Liu",
"Y. T.",
""
],
[
"London",
"L.",
""
],
[
"Lousto",
"C. O.",
""
],
[
"Lovelace",
"G.",
""
],
[
"MacDonald",
"I.",
""
],
[
"Marronetti",
"P.",
""
],
[
"Mösta",
"P.",
""
],
[
"Müller",
"D.",
""
],
[
"Mundim",
"B. C.",
""
],
[
"Nakano",
"H.",
""
],
[
"Paschalidis",
"V.",
""
],
[
"Pekowsky",
"L.",
""
],
[
"Pollney",
"D.",
""
],
[
"Pfeiffer",
"H. P.",
""
],
[
"Ponce",
"M.",
""
],
[
"Pürrer",
"M.",
""
],
[
"Reifenberger",
"G.",
""
],
[
"Reisswig",
"C.",
""
],
[
"Santamaría",
"L.",
""
],
[
"Scheel",
"M. A.",
""
],
[
"Shapiro",
"S. L.",
""
],
[
"Shoemaker",
"D.",
""
],
[
"Sopuerta",
"C. F.",
""
],
[
"Sperhake",
"U.",
""
],
[
"Szilágyi",
"B.",
""
],
[
"Taylor",
"N. W.",
""
],
[
"Tichy",
"W.",
""
],
[
"Tsatsin",
"P.",
""
],
[
"Zlochower",
"Y.",
""
]
] |
The Numerical INJection Analysis (NINJA) project is a collaborative effort between members of the numerical relativity and gravitational-wave astrophysics communities. The purpose of NINJA is to study the ability to detect gravitational waves emitted from merging binary black holes and recover their parameters with next-generation gravitational-wave observatories. We report here on the results of the second NINJA project, NINJA-2, which employs 60 complete binary black hole hybrid waveforms consisting of a numerical portion modelling the late inspiral, merger, and ringdown stitched to a post-Newtonian portion modelling the early inspiral. In a "blind injection challenge" similar to that conducted in recent LIGO and Virgo science runs, we added 7 hybrid waveforms to two months of data recolored to predictions of Advanced LIGO and Advanced Virgo sensitivity curves during their first observing runs. The resulting data was analyzed by gravitational-wave detection algorithms and 6 of the waveforms were recovered with false alarm rates smaller than 1 in a thousand years. Parameter estimation algorithms were run on each of these waveforms to explore the ability to constrain the masses, component angular momenta and sky position of these waveforms. We also perform a large-scale monte-carlo study to assess the ability to recover each of the 60 hybrid waveforms with early Advanced LIGO and Advanced Virgo sensitivity curves. Our results predict that early Advanced LIGO and Advanced Virgo will have a volume-weighted average sensitive distance of 300Mpc (1Gpc) for $10M_{\odot}+10M_{\odot}$ ($50M_{\odot}+50M_{\odot}$) binary black hole coalescences. We demonstrate that neglecting the component angular momenta in the waveform models used in matched-filtering will result in a reduction in sensitivity for systems with large component angular momenta. [Abstract abridged for ArXiv, full version in PDF]
|
gr-qc/9208005
|
Salman Habib
|
Salman Habib and Henry E. Kandrup
|
Nonlinear Noise in Cosmology
|
26 pages
|
Phys.Rev. D46 (1992) 5303-5314
|
10.1103/PhysRevD.46.5303
|
LA-UR-92-2337
|
gr-qc
| null |
This paper derives and analyzes exact, nonlocal Langevin equations
appropriate in a cosmological setting to describe the interaction of some
collective degree of freedom with a surrounding ``environment.'' Formally,
these equations are much more general, involving as they do a more or less
arbitrary ``system,'' characterized by some time-dependent potential, which is
coupled via a nonlinear, time-dependent interaction to a ``bath'' of
oscillators with time-dependent frequencies. The analysis reveals that, even in
a Markov limit, which can often be justified, the time dependences and
nonlinearities can induce new and potentially significant effects, such as
systematic and stochastic mass renormalizations and state-dependent ``memory''
functions, aside from the standard ``friction'' of a heuristic Langevin
description. One specific example is discussed in detail, namely the case of an
inflaton field, characterized by a Landau-Ginsburg potential, that is coupled
quadratically to a bath of scalar ``radiation.'' The principal conclusion
derived from this example is that nonlinearities and time-dependent couplings
do {\em not} preclude the possibility of deriving a fluctuation-dissipation
theorem, and do {\em not} change the form of the late-time steady state
solution for the system, but {\em can} significantly shorten the time scale for
the approach towards the steady state.
|
[
{
"created": "Thu, 13 Aug 1992 06:42:19 GMT",
"version": "v1"
}
] |
2009-10-22
|
[
[
"Habib",
"Salman",
""
],
[
"Kandrup",
"Henry E.",
""
]
] |
This paper derives and analyzes exact, nonlocal Langevin equations appropriate in a cosmological setting to describe the interaction of some collective degree of freedom with a surrounding ``environment.'' Formally, these equations are much more general, involving as they do a more or less arbitrary ``system,'' characterized by some time-dependent potential, which is coupled via a nonlinear, time-dependent interaction to a ``bath'' of oscillators with time-dependent frequencies. The analysis reveals that, even in a Markov limit, which can often be justified, the time dependences and nonlinearities can induce new and potentially significant effects, such as systematic and stochastic mass renormalizations and state-dependent ``memory'' functions, aside from the standard ``friction'' of a heuristic Langevin description. One specific example is discussed in detail, namely the case of an inflaton field, characterized by a Landau-Ginsburg potential, that is coupled quadratically to a bath of scalar ``radiation.'' The principal conclusion derived from this example is that nonlinearities and time-dependent couplings do {\em not} preclude the possibility of deriving a fluctuation-dissipation theorem, and do {\em not} change the form of the late-time steady state solution for the system, but {\em can} significantly shorten the time scale for the approach towards the steady state.
|
2305.18178
|
Riccardo Della Monica
|
Riccardo Della Monica, Ivan de Martino, Mariafelicia de Laurentis
|
Testing space-time geometries and theories of gravity at the Galactic
Center with pulsar's time delay
|
15 pages, 8 figures, 1 table. Accepted for publication in MNRAS
| null |
10.1093/mnras/stad2125
| null |
gr-qc astro-ph.GA astro-ph.HE
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We developed a numerical methodology to compute the fully-relativistic
propagation time of photons emitted by a pulsar in orbit around a massive
compact object, like the supermassive black hole Sagittarius A* in the Galactic
Center, whose gravitational field is described by a generic spherically
symmetric space-time. Pulsars at the Galactic Center are usually regarded as
the next major precision probe for theories of gravity, filling the current
experimental gap between horizon-scale gravity tests and those at larger
scales. We retain a completely general approach, which allows us to apply our
code to the Schwarzschild space-time (by which we successfully validate our
methodology) and to three different well-motivated alternatives to the standard
black hole paradigm. The results of our calculations highlight departures
spanning several orders of magnitudes in timing residuals, that are supposed to
be detectable with future observing facilities like the Square Kilometer Array.
|
[
{
"created": "Mon, 29 May 2023 16:16:26 GMT",
"version": "v1"
},
{
"created": "Thu, 13 Jul 2023 10:21:09 GMT",
"version": "v2"
}
] |
2023-07-20
|
[
[
"Della Monica",
"Riccardo",
""
],
[
"de Martino",
"Ivan",
""
],
[
"de Laurentis",
"Mariafelicia",
""
]
] |
We developed a numerical methodology to compute the fully-relativistic propagation time of photons emitted by a pulsar in orbit around a massive compact object, like the supermassive black hole Sagittarius A* in the Galactic Center, whose gravitational field is described by a generic spherically symmetric space-time. Pulsars at the Galactic Center are usually regarded as the next major precision probe for theories of gravity, filling the current experimental gap between horizon-scale gravity tests and those at larger scales. We retain a completely general approach, which allows us to apply our code to the Schwarzschild space-time (by which we successfully validate our methodology) and to three different well-motivated alternatives to the standard black hole paradigm. The results of our calculations highlight departures spanning several orders of magnitudes in timing residuals, that are supposed to be detectable with future observing facilities like the Square Kilometer Array.
|
gr-qc/0106059
|
S. Antoci
|
S. Antoci and L. Mihich
|
One thing that general relativity says about photons in matter
|
13 pages, 1 figure. Text to appear in Nuovo Cimento B
|
Nuovo Cim.B116:801-812,2001
| null | null |
gr-qc cond-mat quant-ph
| null |
Let us abandon for a moment the strict epistemological standpoint of quantum
field theory, that eventually comes to declare nonsensical any question about
the photon posed outside the quantum theoretical framework. We can then avail
of the works by Whittaker et al. and by Synge about the particle and the wave
model of the photon in the vacuum of general relativity. We can also rely on
important results found by Gordon and by Pham Mau Quan: thanks to Gordon's
discovery of an effective metric these authors have been able to reduce to the
vacuum case several problems of the electromagnetic theory of dielectrics.
The joint use of these old findings allows one to conclude that a quantum
theoretical photon in an isotropic dielectric has a classical simile only if
the dielectric is also homogeneous.
|
[
{
"created": "Tue, 19 Jun 2001 16:01:31 GMT",
"version": "v1"
},
{
"created": "Thu, 26 Jul 2001 16:45:37 GMT",
"version": "v2"
}
] |
2010-11-11
|
[
[
"Antoci",
"S.",
""
],
[
"Mihich",
"L.",
""
]
] |
Let us abandon for a moment the strict epistemological standpoint of quantum field theory, that eventually comes to declare nonsensical any question about the photon posed outside the quantum theoretical framework. We can then avail of the works by Whittaker et al. and by Synge about the particle and the wave model of the photon in the vacuum of general relativity. We can also rely on important results found by Gordon and by Pham Mau Quan: thanks to Gordon's discovery of an effective metric these authors have been able to reduce to the vacuum case several problems of the electromagnetic theory of dielectrics. The joint use of these old findings allows one to conclude that a quantum theoretical photon in an isotropic dielectric has a classical simile only if the dielectric is also homogeneous.
|
gr-qc/0310112
|
Kirill Bronnikov
|
K.A. Bronnikov and V.N. Melnikov
|
Conformal frames and D-dimensional gravity
|
20 pages, to be published in: Proceedings of the 18th Course of the
School on Cosmology and Gravitation: The Gravitational Constant. Generalized
Gravitational Theories and Experiments (30 April-10 May 2003, Erice). Ed. by
G.T. Gillies, V.N. Melnikov and V. de Sabbata (Kluwer) (in print) (2003)
| null |
10.1007/978-1-4020-2242-5_2
| null |
gr-qc
| null |
We review some results concerning the properties of static, spherically
symmetric solutions of multidimensional theories of gravity: various
scalar-tensor theories and a generalized string-motivated model with multiple
scalar fields and fields of antisymmetric forms associated with p-branes. A
Kaluza-Klein type framework is used: there is no dependence on internal
coordinates but multiple internal factor spaces are admitted. We discuss the
causal structure and the existence of black holes, wormholes and particle-like
configurations in the case of scalar vacuum with arbitrary potentials as well
as some observational predictions for exactly solvable systems with p-branes:
post-Newtonian coefficients, Coulomb law violation and black hole temperatures.
Particular attention is paid to conformal frames in which the theory is
initially formulated and which are used for its comparison with observations;
it is stressed that, in general, these two kinds of frames do not coincide.
|
[
{
"created": "Mon, 27 Oct 2003 08:54:39 GMT",
"version": "v1"
}
] |
2015-06-25
|
[
[
"Bronnikov",
"K. A.",
""
],
[
"Melnikov",
"V. N.",
""
]
] |
We review some results concerning the properties of static, spherically symmetric solutions of multidimensional theories of gravity: various scalar-tensor theories and a generalized string-motivated model with multiple scalar fields and fields of antisymmetric forms associated with p-branes. A Kaluza-Klein type framework is used: there is no dependence on internal coordinates but multiple internal factor spaces are admitted. We discuss the causal structure and the existence of black holes, wormholes and particle-like configurations in the case of scalar vacuum with arbitrary potentials as well as some observational predictions for exactly solvable systems with p-branes: post-Newtonian coefficients, Coulomb law violation and black hole temperatures. Particular attention is paid to conformal frames in which the theory is initially formulated and which are used for its comparison with observations; it is stressed that, in general, these two kinds of frames do not coincide.
|
gr-qc/9812064
|
Elizabeth Winstanley
|
E. Winstanley
|
Existence of stable hairy black holes in su(2) Einstein-Yang-Mills
theory with a negative cosmological constant
|
22 pages, 10 figures (1 ps file), LaTeX2e, uses amssymb, graphicx
Minor changes, version to appear in Classical and Quantum Gravity
|
Class.Quant.Grav. 16 (1999) 1963-1978
|
10.1088/0264-9381/16/6/325
|
OUTP-98-92-P
|
gr-qc
| null |
We consider black holes in EYM theory with a negative cosmological constant.
The solutions obtained are somewhat different from those for which the
cosmological constant is either positive or zero. Firstly, regular black hole
solutions exist for continuous intervals of the parameter space, rather than
discrete points. Secondly, there are non-trivial solutions in which the gauge
field has no nodes. We show that these solutions are linearly stable.
|
[
{
"created": "Thu, 17 Dec 1998 17:35:42 GMT",
"version": "v1"
},
{
"created": "Thu, 29 Apr 1999 16:49:33 GMT",
"version": "v2"
}
] |
2009-10-31
|
[
[
"Winstanley",
"E.",
""
]
] |
We consider black holes in EYM theory with a negative cosmological constant. The solutions obtained are somewhat different from those for which the cosmological constant is either positive or zero. Firstly, regular black hole solutions exist for continuous intervals of the parameter space, rather than discrete points. Secondly, there are non-trivial solutions in which the gauge field has no nodes. We show that these solutions are linearly stable.
|
gr-qc/0104092
|
Kirill Bronnikov
|
Kirill A. Bronnikov (VNIIMS, Moscow; PFUR, Moscow)
|
Spherically symmetric false vacuum: no-go theorems and global structure
|
Latex2e, 4 pages, 1 bezier figure
|
Phys.Rev.D64:064013,2001
|
10.1103/PhysRevD.64.064013
| null |
gr-qc hep-th
| null |
We enumerate all possible types of spacetime causal structures that can
appear in static, spherically symmetric configurations of a self-gravitating,
real, nonlinear, minimally coupled scalar field \phi in general relativity,
with an arbitrary potential V(\phi), not necessarily positive-definite. It is
shown that a variable scalar field adds nothing to the list of possible
structures with a constant \phi field, namely, Minkowski (or AdS),
Schwarzschild, de Sitter and Schwarzschild - de Sitter. It follows, in
particular, that, whatever is V(\phi), this theory does not admit regular black
holes with flat or AdS asymptotics. It is concluded that the only possible
globally regular, asymptotically flat solutions are solitons with a regular
center, without horizons and with at least partly negative potentials V(\phi).
Extension of the results to more general field models is discussed.
|
[
{
"created": "Fri, 27 Apr 2001 14:47:46 GMT",
"version": "v1"
}
] |
2014-11-17
|
[
[
"Bronnikov",
"Kirill A.",
"",
"VNIIMS, Moscow; PFUR, Moscow"
]
] |
We enumerate all possible types of spacetime causal structures that can appear in static, spherically symmetric configurations of a self-gravitating, real, nonlinear, minimally coupled scalar field \phi in general relativity, with an arbitrary potential V(\phi), not necessarily positive-definite. It is shown that a variable scalar field adds nothing to the list of possible structures with a constant \phi field, namely, Minkowski (or AdS), Schwarzschild, de Sitter and Schwarzschild - de Sitter. It follows, in particular, that, whatever is V(\phi), this theory does not admit regular black holes with flat or AdS asymptotics. It is concluded that the only possible globally regular, asymptotically flat solutions are solitons with a regular center, without horizons and with at least partly negative potentials V(\phi). Extension of the results to more general field models is discussed.
|
2204.05997
|
Ashkan Alibabaei
|
Ashkan Alibabaei
|
Geometric post-Newtonian description of spin-half particles in curved
spacetime
|
Master's thesis, 8+77 pages, 3 figures. v2: corrected typos, updated
discussion in chapter 5, removed double references. v3: corrected further
typos
| null |
10.15488/11949
| null |
gr-qc hep-th math-ph math.MP quant-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Einstein Equivalence Principle (EEP) requires all matter components to
universally couple to gravity via a single common geometry: that of spacetime.
This relates quantum theory with geometry as soon as interactions with gravity
are considered. In this work, I study the geometric theory of coupling a
spin-1/2 particle to gravity in a twofold expansion scheme: First with respect
to the distance based on Fermi normal coordinates around a preferred worldline
(e.g., that of a clock in the laboratory), second with respect to 1/c
(post-Newtonian expansion). I consider the one-particle sector of a massive
spinor field in QFT, here described effectively by a classical field. The
formal expansion in powers of 1/c yields a systematic and complete generation
of GR corrections for quantum systems. I find new terms that were overlooked in
the literature at order 1/c^2 and extended the level of approximation to the
next order. These findings are significant for a consistent inclusion of
gravity corrections in the description of quantum experiments of corresponding
sensitivities, and also for testing aspects of GR, like the EEP, in the quantum
realm.
|
[
{
"created": "Tue, 12 Apr 2022 13:39:09 GMT",
"version": "v1"
},
{
"created": "Thu, 2 Jun 2022 17:50:22 GMT",
"version": "v2"
},
{
"created": "Mon, 12 Sep 2022 14:12:40 GMT",
"version": "v3"
}
] |
2022-09-13
|
[
[
"Alibabaei",
"Ashkan",
""
]
] |
Einstein Equivalence Principle (EEP) requires all matter components to universally couple to gravity via a single common geometry: that of spacetime. This relates quantum theory with geometry as soon as interactions with gravity are considered. In this work, I study the geometric theory of coupling a spin-1/2 particle to gravity in a twofold expansion scheme: First with respect to the distance based on Fermi normal coordinates around a preferred worldline (e.g., that of a clock in the laboratory), second with respect to 1/c (post-Newtonian expansion). I consider the one-particle sector of a massive spinor field in QFT, here described effectively by a classical field. The formal expansion in powers of 1/c yields a systematic and complete generation of GR corrections for quantum systems. I find new terms that were overlooked in the literature at order 1/c^2 and extended the level of approximation to the next order. These findings are significant for a consistent inclusion of gravity corrections in the description of quantum experiments of corresponding sensitivities, and also for testing aspects of GR, like the EEP, in the quantum realm.
|
gr-qc/0106016
|
Eric Gourgoulhon
|
Philippe Grandcl\'ement, Eric Gourgoulhon and Silvano Bonazzola (DARC,
CNRS, Observatoire de Paris)
|
Binary black holes in circular orbits. II. Numerical methods and first
results
|
27 pages, 20 PostScript figures, improved presentation of the
regularization procedure for the shift vector, new section devoted to the
check of the momentum constraint, references added + minor corrections,
accepted for publication in Phys. Rev. D
|
Phys.Rev. D65 (2002) 044021
|
10.1103/PhysRevD.65.044021
| null |
gr-qc astro-ph
| null |
We present the first results from a new method for computing spacetimes
representing corotating binary black holes in circular orbits. The method is
based on the assumption of exact equilibrium. It uses the standard 3+1
decomposition of Einstein equations and conformal flatness approximation for
the 3-metric. Contrary to previous numerical approaches to this problem, we do
not solve only the constraint equations but rather a set of five equations for
the lapse function, the conformal factor and the shift vector. The orbital
velocity is unambiguously determined by imposing that, at infinity, the metric
behaves like the Schwarzschild one, a requirement which is equivalent to the
virial theorem. The numerical scheme has been implemented using multi-domain
spectral methods and passed numerous tests. A sequence of corotating black
holes of equal mass is calculated. Defining the sequence by requiring that the
ADM mass decrease is equal to the angular momentum decrease multiplied by the
orbital angular velocity, it is found that the area of the apparent horizons is
constant along the sequence. We also find a turning point in the ADM mass and
angular momentum curves, which may be interpreted as an innermost stable
circular orbit (ISCO). The values of the global quantities at the ISCO,
especially the orbital velocity, are in much better agreement with those from
third post-Newtonian calculations than with those resulting from previous
numerical approaches.
|
[
{
"created": "Tue, 5 Jun 2001 20:51:47 GMT",
"version": "v1"
},
{
"created": "Mon, 18 Jun 2001 09:20:41 GMT",
"version": "v2"
},
{
"created": "Fri, 28 Sep 2001 14:54:02 GMT",
"version": "v3"
},
{
"created": "Thu, 8 Nov 2001 21:29:41 GMT",
"version": "v4"
}
] |
2009-11-07
|
[
[
"Grandclément",
"Philippe",
"",
"DARC,\n CNRS, Observatoire de Paris"
],
[
"Gourgoulhon",
"Eric",
"",
"DARC,\n CNRS, Observatoire de Paris"
],
[
"Bonazzola",
"Silvano",
"",
"DARC,\n CNRS, Observatoire de Paris"
]
] |
We present the first results from a new method for computing spacetimes representing corotating binary black holes in circular orbits. The method is based on the assumption of exact equilibrium. It uses the standard 3+1 decomposition of Einstein equations and conformal flatness approximation for the 3-metric. Contrary to previous numerical approaches to this problem, we do not solve only the constraint equations but rather a set of five equations for the lapse function, the conformal factor and the shift vector. The orbital velocity is unambiguously determined by imposing that, at infinity, the metric behaves like the Schwarzschild one, a requirement which is equivalent to the virial theorem. The numerical scheme has been implemented using multi-domain spectral methods and passed numerous tests. A sequence of corotating black holes of equal mass is calculated. Defining the sequence by requiring that the ADM mass decrease is equal to the angular momentum decrease multiplied by the orbital angular velocity, it is found that the area of the apparent horizons is constant along the sequence. We also find a turning point in the ADM mass and angular momentum curves, which may be interpreted as an innermost stable circular orbit (ISCO). The values of the global quantities at the ISCO, especially the orbital velocity, are in much better agreement with those from third post-Newtonian calculations than with those resulting from previous numerical approaches.
|
gr-qc/0212040
|
Marc Mars
|
Edward Malec, Marc Mars, Walter Simon
|
On the Penrose Inequality
|
6 pages, no figures. To appear in the Proceedings of the Spanish
Relativity Meeting (ERE 2002), Mao, Menorca, Spain, 22-24 Sept 2002
| null | null |
ERE-2002-01
|
gr-qc
| null |
We summarize results on the Penrose inequality bounding the ADM-mass or the
Bondi mass in terms of the area of an outermost apparent horizon for
asymptotically flat initial data of Einstein's equations. We first recall the
proof, due to Geroch and to Jang and Wald, of monotonicity of the
Geroch-Hawking mass under a smooth inverse mean curvature flow for data with
non-negative Ricci scalar, which leads to a Penrose inequality if the apparent
horizon is a minimal surface.We then sketch a proof of the Penrose inequality
of Malec, Mars and Simon which holds for general horizons and for data
satisfying the dominant energy condition, but imposes (in addition to smooth
inverse mean curvature flow) suitable restrictions on the data on a spacelike
surface. These conditions can, however, at least locally be fulfilled by a
suitable choice of the initial surface in a given spacetime. Remarkably, they
are also (formally) identical to ones employed earlier by Hayward in order to
define a 2+1 foliation on null surfaces, with respect to which the Hawking mass
is again monotonic.
|
[
{
"created": "Mon, 9 Dec 2002 15:44:42 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Malec",
"Edward",
""
],
[
"Mars",
"Marc",
""
],
[
"Simon",
"Walter",
""
]
] |
We summarize results on the Penrose inequality bounding the ADM-mass or the Bondi mass in terms of the area of an outermost apparent horizon for asymptotically flat initial data of Einstein's equations. We first recall the proof, due to Geroch and to Jang and Wald, of monotonicity of the Geroch-Hawking mass under a smooth inverse mean curvature flow for data with non-negative Ricci scalar, which leads to a Penrose inequality if the apparent horizon is a minimal surface.We then sketch a proof of the Penrose inequality of Malec, Mars and Simon which holds for general horizons and for data satisfying the dominant energy condition, but imposes (in addition to smooth inverse mean curvature flow) suitable restrictions on the data on a spacelike surface. These conditions can, however, at least locally be fulfilled by a suitable choice of the initial surface in a given spacetime. Remarkably, they are also (formally) identical to ones employed earlier by Hayward in order to define a 2+1 foliation on null surfaces, with respect to which the Hawking mass is again monotonic.
|
1411.0829
|
Christian Corda Prof.
|
Ignazio Licata, Christian Corda, Elmo Benedetto
|
A Machian Request for the Equivalence Principle in Extended Gravity and
non-geodesic motion
|
11 pages, accepted for publication in Gravitation and Cosmology, to
appear in in vol. 22, issue 1 (2016) of the journal
|
Grav. Cosm. 22, 1, 48 (2016)
|
10.1134/S0202289316010102
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Starting from the origin of Einstein general relativity (GR) the request of
Mach on the theory's structure has been the core of the foundational debate.
That problem is strictly connected with the nature of the mass-energy
equivalence. It is well known that this is exactly the key point that Einstein
used to realize a metric theory of gravitation having an unequalled beauty and
elegance. On the other hand, the current requirements of particle physics and
the open questions within extended gravity theories request a better
understanding of Equivalence Principle (EP). The MOND theory by Milgrom
proposes a modification of Newtonian dynamics and we consider a direct coupling
between the Ricci curvature scalar and the matter Lagrangian showing that a non
geodesic ratio m_{i}/m_{g} can be fixed and that Milgrom acceleration is
retrieved at low energies.
|
[
{
"created": "Tue, 4 Nov 2014 08:59:09 GMT",
"version": "v1"
},
{
"created": "Sat, 26 Sep 2015 08:16:53 GMT",
"version": "v2"
}
] |
2016-04-07
|
[
[
"Licata",
"Ignazio",
""
],
[
"Corda",
"Christian",
""
],
[
"Benedetto",
"Elmo",
""
]
] |
Starting from the origin of Einstein general relativity (GR) the request of Mach on the theory's structure has been the core of the foundational debate. That problem is strictly connected with the nature of the mass-energy equivalence. It is well known that this is exactly the key point that Einstein used to realize a metric theory of gravitation having an unequalled beauty and elegance. On the other hand, the current requirements of particle physics and the open questions within extended gravity theories request a better understanding of Equivalence Principle (EP). The MOND theory by Milgrom proposes a modification of Newtonian dynamics and we consider a direct coupling between the Ricci curvature scalar and the matter Lagrangian showing that a non geodesic ratio m_{i}/m_{g} can be fixed and that Milgrom acceleration is retrieved at low energies.
|
2403.12240
|
Thomas Colas
|
C.P. Burgess, Thomas Colas, R. Holman, Greg Kaplanek and Vincent
Vennin
|
Cosmic Purity Lost: Perturbative and Resummed Late-Time Inflationary
Decoherence
|
37 pages plus appendices, 7 figures; typos corrected
| null | null | null |
gr-qc astro-ph.CO hep-ph hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We compute the rate with which unobserved fields decohere other fields to
which they couple, both in flat space and in de Sitter space, for scalar fields
prepared in their standard adiabatic vacuum. The process is very efficient in
de Sitter space once the modes in question pass outside the Hubble scale,
displaying the tell-tale phenomenon of secular growth that indicates the
breakdown of perturbative methods on a time scale parameterically long compared
with the Hubble time. We show how to match the perturbative evolution valid at
early times onto a late-time Lindblad evolution whose domain of validity
extends to much later times, thereby allowing a reliable resummation of the
perturbative result beyond the perturbative regime. Super-Hubble modes turn out
to be dominantly decohered by unobserved modes that are themselves also
super-Hubble. When applied to curvature perturbations during inflation this
observation closes a potential loophole in recent calculations of the late-time
purity of the observable primordial fluctuations.
|
[
{
"created": "Mon, 18 Mar 2024 20:44:42 GMT",
"version": "v1"
},
{
"created": "Wed, 17 Apr 2024 12:10:44 GMT",
"version": "v2"
}
] |
2024-04-18
|
[
[
"Burgess",
"C. P.",
""
],
[
"Colas",
"Thomas",
""
],
[
"Holman",
"R.",
""
],
[
"Kaplanek",
"Greg",
""
],
[
"Vennin",
"Vincent",
""
]
] |
We compute the rate with which unobserved fields decohere other fields to which they couple, both in flat space and in de Sitter space, for scalar fields prepared in their standard adiabatic vacuum. The process is very efficient in de Sitter space once the modes in question pass outside the Hubble scale, displaying the tell-tale phenomenon of secular growth that indicates the breakdown of perturbative methods on a time scale parameterically long compared with the Hubble time. We show how to match the perturbative evolution valid at early times onto a late-time Lindblad evolution whose domain of validity extends to much later times, thereby allowing a reliable resummation of the perturbative result beyond the perturbative regime. Super-Hubble modes turn out to be dominantly decohered by unobserved modes that are themselves also super-Hubble. When applied to curvature perturbations during inflation this observation closes a potential loophole in recent calculations of the late-time purity of the observable primordial fluctuations.
|
gr-qc/9611012
|
Nicholas G. Phillips
|
Nicholas G. Phillips, B. L. Hu
|
Fluctuations of the vacuum energy density of quantum fields in curved
spacetime via generalized zeta functions
|
Uses revtex
|
Phys.Rev. D55 (1997) 6123-6134
|
10.1103/PhysRevD.55.6123
|
UMDPP#97-58
|
gr-qc
| null |
For quantum fields on a curved spacetime with an Euclidean section, we derive
a general expression for the stress energy tensor two-point function in terms
of the effective action. The renormalized two-point function is given in terms
of the second variation of the Mellin transform of the trace of the heat kernel
for the quantum fields. For systems for which a spectral decomposition of the
wave opearator is possible, we give an exact expression for this two-point
function. Explicit examples of the variance to the mean ratio $\Delta' =
(<\rho^2>-<\rho>^2)/(<\rho>^2)$ of the vacuum energy density $\rho$ of a
massless scalar field are computed for the spatial topologies of $R^d\times
S^1$ and $S^3$, with results of $\Delta'(R^d\times S^1) =(d+1)(d+2)/2$, and
$\Delta'(S^3) = 111$ respectively. The large variance signifies the importance
of quantum fluctuations and has important implications for the validity of
semiclassical gravity theories at sub-Planckian scales. The method presented
here can facilitate the calculation of stress-energy fluctuations for quantum
fields useful for the analysis of fluctuation effects and critical phenomena in
problems ranging from atom optics and mesoscopic physics to early universe and
black hole physics.
|
[
{
"created": "Tue, 5 Nov 1996 19:47:39 GMT",
"version": "v1"
}
] |
2016-08-31
|
[
[
"Phillips",
"Nicholas G.",
""
],
[
"Hu",
"B. L.",
""
]
] |
For quantum fields on a curved spacetime with an Euclidean section, we derive a general expression for the stress energy tensor two-point function in terms of the effective action. The renormalized two-point function is given in terms of the second variation of the Mellin transform of the trace of the heat kernel for the quantum fields. For systems for which a spectral decomposition of the wave opearator is possible, we give an exact expression for this two-point function. Explicit examples of the variance to the mean ratio $\Delta' = (<\rho^2>-<\rho>^2)/(<\rho>^2)$ of the vacuum energy density $\rho$ of a massless scalar field are computed for the spatial topologies of $R^d\times S^1$ and $S^3$, with results of $\Delta'(R^d\times S^1) =(d+1)(d+2)/2$, and $\Delta'(S^3) = 111$ respectively. The large variance signifies the importance of quantum fluctuations and has important implications for the validity of semiclassical gravity theories at sub-Planckian scales. The method presented here can facilitate the calculation of stress-energy fluctuations for quantum fields useful for the analysis of fluctuation effects and critical phenomena in problems ranging from atom optics and mesoscopic physics to early universe and black hole physics.
|
gr-qc/0210068
|
Burc Gokden
|
Burc Gokden
|
Study of a formalism modeling massive particles at the speed of light on
a Machian basis
|
12 pages, 1 figure, written using Revtex4, new arguments added
| null | null | null |
gr-qc
| null |
In this paper we develop a formalism which models all massive particles as
travelling at the speed of light(c). This is done by completing the 3-velocity
v of a test particle to the speed of light by adding an auxiliary 3-velocity
component z for the particle. According to the observations and laws of physics
defined in our spacetime these vectors are generalized to domains and then two
methods are developed to define c domain in terms of our spacetime(v domain).
By using these methods the formalism is applied on relativistic quantum theory
and general theory of relativity. From these, the relation between the
formalism and Mach's principle is investigated. The ideas and formulae
developed from application of the formalism on general relativity are compared
with the characteristics of anomalous accelerations detected on Pioneer 10/11,
Ulysses and Galileo spacecrafts and an explanation according to the formalism
is suggested. Possible relationships between Mach's principle and the
nondeterministic nature of the universe are also explored. In this study Mach's
principle, on which current debate still continues, is expressed from an
unconventional point of view, as a naturally arising consequence of the
formalism, and the approaches are simplified accordingly.
|
[
{
"created": "Sat, 19 Oct 2002 19:59:22 GMT",
"version": "v1"
},
{
"created": "Wed, 22 Jan 2003 22:26:10 GMT",
"version": "v2"
}
] |
2007-05-23
|
[
[
"Gokden",
"Burc",
""
]
] |
In this paper we develop a formalism which models all massive particles as travelling at the speed of light(c). This is done by completing the 3-velocity v of a test particle to the speed of light by adding an auxiliary 3-velocity component z for the particle. According to the observations and laws of physics defined in our spacetime these vectors are generalized to domains and then two methods are developed to define c domain in terms of our spacetime(v domain). By using these methods the formalism is applied on relativistic quantum theory and general theory of relativity. From these, the relation between the formalism and Mach's principle is investigated. The ideas and formulae developed from application of the formalism on general relativity are compared with the characteristics of anomalous accelerations detected on Pioneer 10/11, Ulysses and Galileo spacecrafts and an explanation according to the formalism is suggested. Possible relationships between Mach's principle and the nondeterministic nature of the universe are also explored. In this study Mach's principle, on which current debate still continues, is expressed from an unconventional point of view, as a naturally arising consequence of the formalism, and the approaches are simplified accordingly.
|
1909.12848
|
Kwinten Fransen
|
Geoffrey Comp\`ere, Kwinten Fransen and Caroline Jonas
|
Transition from inspiral to plunge into a highly spinning black hole
|
9 pages, published version
| null |
10.1088/1361-6382/ab79d3
| null |
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We extend the Ori-Thorne-Kesden procedure to consistently describe the
non-quasi-circular transition around the ISCO from inspiral to plunge into a
black hole of arbitrary spin, including near-extremal. We identify that for
moderate or high spins the transition is governed by the Painlev\'e
transcendent equation of the first kind while for extremely high spins it is
governed by a self-similar solution to the Korteweg-de Vries equation. We match
the transition solution at leading order in the high spin limit with the
analytical quasi-circular inspiral in the near-horizon region. We also show
that the central black hole of an extreme mass ratio binary has a
near-extremality parameter that scales at least as the mass ratio due to
superradiant gravitational wave emission, which excludes extremely high spins.
|
[
{
"created": "Fri, 27 Sep 2019 18:00:04 GMT",
"version": "v1"
},
{
"created": "Thu, 2 Apr 2020 14:27:30 GMT",
"version": "v2"
}
] |
2020-06-17
|
[
[
"Compère",
"Geoffrey",
""
],
[
"Fransen",
"Kwinten",
""
],
[
"Jonas",
"Caroline",
""
]
] |
We extend the Ori-Thorne-Kesden procedure to consistently describe the non-quasi-circular transition around the ISCO from inspiral to plunge into a black hole of arbitrary spin, including near-extremal. We identify that for moderate or high spins the transition is governed by the Painlev\'e transcendent equation of the first kind while for extremely high spins it is governed by a self-similar solution to the Korteweg-de Vries equation. We match the transition solution at leading order in the high spin limit with the analytical quasi-circular inspiral in the near-horizon region. We also show that the central black hole of an extreme mass ratio binary has a near-extremality parameter that scales at least as the mass ratio due to superradiant gravitational wave emission, which excludes extremely high spins.
|
1103.2311
|
Giuseppe De Risi
|
G. De Risi
|
Cosmological backreaction of heavy string states
|
13 pages, 1 figure, The discussion on the results has been extended.
To be published on MPLA
| null |
10.1142/S0217732311036991
|
BA-TH/11-642
|
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We propose a mechanism to have a smooth transition from a pre-Big Bang phase
to a standard cosmological phase. Such transition is driven by gravitational
production of heavy massive string states that backreact on the geometry to
stop the growth of the curvature. Close to the string scale, particle creation
can become effective because the string phase space compensate the exponential
suppression of the particle production. Numerical solutions for the evolution
of the Universe with this source are presented.
|
[
{
"created": "Fri, 11 Mar 2011 16:45:12 GMT",
"version": "v1"
},
{
"created": "Wed, 19 Oct 2011 10:42:32 GMT",
"version": "v2"
}
] |
2015-05-27
|
[
[
"De Risi",
"G.",
""
]
] |
We propose a mechanism to have a smooth transition from a pre-Big Bang phase to a standard cosmological phase. Such transition is driven by gravitational production of heavy massive string states that backreact on the geometry to stop the growth of the curvature. Close to the string scale, particle creation can become effective because the string phase space compensate the exponential suppression of the particle production. Numerical solutions for the evolution of the Universe with this source are presented.
|
gr-qc/0105015
|
Kohkichi Konno
|
K. Konno
|
Moments of inertia of relativistic magnetized stars
|
7 pages, 3 figures, accepted for publication in Astronomy and
Astrophysics
|
Astron.Astrophys.372:594,2001
|
10.1051/0004-6361:20010556
| null |
gr-qc astro-ph
| null |
We consider principal moments of inertia of axisymmetric, magnetically
deformed stars in the context of general relativity. The general expression for
the moment of inertia with respect to the symmetric axis is obtained. The
numerical estimates are derived for several polytropic stellar models. We find
that the values of the principal moments of inertia are modified by a factor of
2 at most from Newtonian estimates.
|
[
{
"created": "Thu, 3 May 2001 11:27:44 GMT",
"version": "v1"
}
] |
2008-11-26
|
[
[
"Konno",
"K.",
""
]
] |
We consider principal moments of inertia of axisymmetric, magnetically deformed stars in the context of general relativity. The general expression for the moment of inertia with respect to the symmetric axis is obtained. The numerical estimates are derived for several polytropic stellar models. We find that the values of the principal moments of inertia are modified by a factor of 2 at most from Newtonian estimates.
|
2203.13757
|
Joan Sola
|
Joan Sola Peracaula
|
The Cosmological Constant Problem and Running Vacuum in the Expanding
Universe
|
Matches the published version in Phil.Trans.Roy.Soc.Lond.A (2022)
|
Phil. Trans. R. Soc. A 380 (2022) 20210182
|
10.1098/rsta.2021.0182
| null |
gr-qc astro-ph.CO hep-ph hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
It is well-known that quantum field theory (QFT) induces a huge value of the
cosmological constant, $\Lambda$, which is outrageously inconsistent with
cosmological observations. We review here some aspects of this fundamental
theoretical conundrum (`the cosmological constant problem') and strongly argue
in favor of the possibility that the cosmic vacuum density $\rho_{\rm vac}$ may
be mildly evolving with the expansion rate $H$. Such a `running vacuum model'
(RVM) proposal predicts an effective dynamical dark energy without postulating
new ad hoc fields (quintessence and the like). Using the method of adiabatic
renormalization within QFT in curved spacetime we find that $\rho_{\rm vac}(H)$
acquires a dynamical component ${\cal O}(H^2)$ caused by the quantum matter
effects. There are also ${\cal O}(H^n)$ ($n=4,6,..$) contributions, some of
which may trigger inflation in the early universe. Remarkably, the evolution of
the adiabatically renormalized $\rho_{\rm vac}(H)$ is not affected by dangerous
terms proportional to the quartic power of the masses ($\sim m^4$) of the
fields. Traditionally, these terms have been the main source of trouble as they
are responsible for the extreme fine tuning feature of the cosmological
constant problem. In the context under study, however, the late time $\rho_{\rm
vac}(H)$ around $H_0$ is given by a dominant term ($\rho_{\rm vac}^0$) plus the
aforementioned mild dynamical component $\propto \nu (H^2-H_0^2)$ (with
$|\nu|\ll1$), which makes the RVM to mimic quintessence. Finally, on the
phenomenological side we show that the RVM may be instrumental in alleviating
some of the most challenging problems (so-called `tensions') afflicting
nowadays the observational consistency of the `concordance' $\Lambda$CDM model,
such as the $H_0$ and $\sigma_8$ tensions.
|
[
{
"created": "Fri, 25 Mar 2022 16:36:38 GMT",
"version": "v1"
},
{
"created": "Sun, 17 Jul 2022 18:15:10 GMT",
"version": "v2"
}
] |
2022-07-19
|
[
[
"Peracaula",
"Joan Sola",
""
]
] |
It is well-known that quantum field theory (QFT) induces a huge value of the cosmological constant, $\Lambda$, which is outrageously inconsistent with cosmological observations. We review here some aspects of this fundamental theoretical conundrum (`the cosmological constant problem') and strongly argue in favor of the possibility that the cosmic vacuum density $\rho_{\rm vac}$ may be mildly evolving with the expansion rate $H$. Such a `running vacuum model' (RVM) proposal predicts an effective dynamical dark energy without postulating new ad hoc fields (quintessence and the like). Using the method of adiabatic renormalization within QFT in curved spacetime we find that $\rho_{\rm vac}(H)$ acquires a dynamical component ${\cal O}(H^2)$ caused by the quantum matter effects. There are also ${\cal O}(H^n)$ ($n=4,6,..$) contributions, some of which may trigger inflation in the early universe. Remarkably, the evolution of the adiabatically renormalized $\rho_{\rm vac}(H)$ is not affected by dangerous terms proportional to the quartic power of the masses ($\sim m^4$) of the fields. Traditionally, these terms have been the main source of trouble as they are responsible for the extreme fine tuning feature of the cosmological constant problem. In the context under study, however, the late time $\rho_{\rm vac}(H)$ around $H_0$ is given by a dominant term ($\rho_{\rm vac}^0$) plus the aforementioned mild dynamical component $\propto \nu (H^2-H_0^2)$ (with $|\nu|\ll1$), which makes the RVM to mimic quintessence. Finally, on the phenomenological side we show that the RVM may be instrumental in alleviating some of the most challenging problems (so-called `tensions') afflicting nowadays the observational consistency of the `concordance' $\Lambda$CDM model, such as the $H_0$ and $\sigma_8$ tensions.
|
2005.11038
|
Angel Rincon
|
Francisco Tello-Ortiz, M. Malaver, Angel Rincon and Y. Gomez-Leyton
|
Relativistic Anisotropic Fluid Spheres Satisfying a Non-Linear Equation
of State
|
13 pages, 5 figures. Published in EPJ C
|
Eur. Phys. J. C 80, 371 (2020)
|
10.1140/epjc/s10052-020-7956-0
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
In this work, a spherically symmetric and static relativistic anisotropic
fluid sphere solution of the Einstein field equations is provided. To build
this particular model, we have imposed metric potential $e^{2\lambda(r)}$ and
an equation of state. Specifically, the so-called modified generalized
Chaplygin equation of state with $\omega=1$ and depending on two parameters,
namely, $A$ and $B$. These ingredients close the problem, at least
mathematically. However, to check the feasibility of the model, a complete
physical analysis has been performed. Thus, we analyze the obtained geometry
and the main physical observables, such as the density $\rho$, the radial
$p_{r}$, and tangential $p_{t}$ pressures as well as the anisotropy factor
$\Delta$. Besides, the stability of the system has been checked by means of the
velocities of the pressure waves and the relativistic adiabatic index. It is
found that the configuration is stable in considering the adiabatic index
criteria and is under hydrostatic balance. Finally, to mimic a realistic
compact object, we have imposed the radius to be $R=9.5\ [km]$. With this
information and taking different values of the parameter $A$ the total mass of
the object has been determined. The resulting numerical values for the
principal variables of the model established that the structure could represent
a quark (strange) star mixed with dark energy.
|
[
{
"created": "Fri, 22 May 2020 07:19:40 GMT",
"version": "v1"
}
] |
2020-05-25
|
[
[
"Tello-Ortiz",
"Francisco",
""
],
[
"Malaver",
"M.",
""
],
[
"Rincon",
"Angel",
""
],
[
"Gomez-Leyton",
"Y.",
""
]
] |
In this work, a spherically symmetric and static relativistic anisotropic fluid sphere solution of the Einstein field equations is provided. To build this particular model, we have imposed metric potential $e^{2\lambda(r)}$ and an equation of state. Specifically, the so-called modified generalized Chaplygin equation of state with $\omega=1$ and depending on two parameters, namely, $A$ and $B$. These ingredients close the problem, at least mathematically. However, to check the feasibility of the model, a complete physical analysis has been performed. Thus, we analyze the obtained geometry and the main physical observables, such as the density $\rho$, the radial $p_{r}$, and tangential $p_{t}$ pressures as well as the anisotropy factor $\Delta$. Besides, the stability of the system has been checked by means of the velocities of the pressure waves and the relativistic adiabatic index. It is found that the configuration is stable in considering the adiabatic index criteria and is under hydrostatic balance. Finally, to mimic a realistic compact object, we have imposed the radius to be $R=9.5\ [km]$. With this information and taking different values of the parameter $A$ the total mass of the object has been determined. The resulting numerical values for the principal variables of the model established that the structure could represent a quark (strange) star mixed with dark energy.
|
gr-qc/0212121
| null |
Sergei M. Kopeikin (Department of Physics and Astronomy, University of
Missouri-Columbia, USA)
|
The Post-Newtonian Treatment of the VLBI Experiment on September 8, 2002
|
15 pages, 2 figures, final version accepted to Phys. Lett. A
|
Phys.Lett. A312 (2003) 147-157
|
10.1016/S0375-9601(03)00613-3
| null |
gr-qc astro-ph hep-ph hep-th
| null |
Gravitational physics of VLBI experiment conducted on September 8, 2002 and
dedicated to measure the speed of gravity (a fundamental constant in the
Einstein equations) is treated in the first post-Newtonian approximation.
Explicit speed-of-gravity parameterization is introduced to the Einstein
equations to single out the retardation effect caused by the finite speed of
gravity in the relativistic time delay of light, passing through the variable
gravitational field of the solar system. The speed-of-gravity 1.5
post-Newtonian correction to the Shapiro time delay is derived and compared
with our previous result obtained by making use of the post-Minkowskian
approximation. We confirm that the 1.5 post-Newtonian correction to the Shapiro
delay depends on the speed of gravity $c_g$ that is a directly measurable
parameter in the VLBI experiment.
|
[
{
"created": "Mon, 30 Dec 2002 03:01:05 GMT",
"version": "v1"
},
{
"created": "Fri, 10 Jan 2003 19:09:57 GMT",
"version": "v2"
},
{
"created": "Tue, 18 Feb 2003 21:39:22 GMT",
"version": "v3"
},
{
"created": "Fri, 28 Mar 2003 21:59:09 GMT",
"version": "v4"
}
] |
2007-05-23
|
[
[
"Kopeikin",
"Sergei M.",
"",
"Department of Physics and Astronomy, University of\n Missouri-Columbia, USA"
]
] |
Gravitational physics of VLBI experiment conducted on September 8, 2002 and dedicated to measure the speed of gravity (a fundamental constant in the Einstein equations) is treated in the first post-Newtonian approximation. Explicit speed-of-gravity parameterization is introduced to the Einstein equations to single out the retardation effect caused by the finite speed of gravity in the relativistic time delay of light, passing through the variable gravitational field of the solar system. The speed-of-gravity 1.5 post-Newtonian correction to the Shapiro time delay is derived and compared with our previous result obtained by making use of the post-Minkowskian approximation. We confirm that the 1.5 post-Newtonian correction to the Shapiro delay depends on the speed of gravity $c_g$ that is a directly measurable parameter in the VLBI experiment.
|
1203.3223
|
Carlos O. Lousto
|
Carlos O. Lousto, Hiroyuki Nakano, Yosef Zlochower, Bruno C. Mundim,
Manuela Campanelli (RIT)
|
Study of Conformally Flat Initial Data for Highly Spinning Black Holes
and their Early Evolutions
|
9 pages, 8 figures
| null |
10.1103/PhysRevD.85.124013
| null |
gr-qc astro-ph.CO astro-ph.GA astro-ph.HE
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We study conformally-flat initial data for an arbitrary number of spinning
black holes with exact analytic solutions to the momentum constraints
constructed from a linear combination of the classical Bowen-York and conformal
Kerr extrinsic curvatures. The solution leading to the largest intrinsic spin,
relative to the ADM mass of the spacetime epsilon_S=S/M^2_{ADM}, is a
superposition with relative weights of Lambda=0.783 for conformal Kerr and
(1-Lambda)=0.217 for Bowen-York. In addition, we measure the spin relative to
the initial horizon mass M_{H_0}, and find that the quantity chi=S/M_{H_0}^2
reaches a maximum of \chi^{max}=0.9856 for Lambda=0.753. After equilibration,
the final black-hole spin should lie in the interval 0.9324<chi_{final}<0.9856.
We perform full numerical evolutions to compute the energy radiated and the
final horizon mass and spin. We find that the black hole settles to a final
spin of chi_{final}^{max}=0.935 when Lambda=0.783. We also study the evolution
of the apparent horizon structure of this "maximal" black hole in detail.
|
[
{
"created": "Wed, 14 Mar 2012 21:52:17 GMT",
"version": "v1"
},
{
"created": "Thu, 14 Jun 2012 18:29:20 GMT",
"version": "v2"
}
] |
2012-06-15
|
[
[
"Lousto",
"Carlos O.",
"",
"RIT"
],
[
"Nakano",
"Hiroyuki",
"",
"RIT"
],
[
"Zlochower",
"Yosef",
"",
"RIT"
],
[
"Mundim",
"Bruno C.",
"",
"RIT"
],
[
"Campanelli",
"Manuela",
"",
"RIT"
]
] |
We study conformally-flat initial data for an arbitrary number of spinning black holes with exact analytic solutions to the momentum constraints constructed from a linear combination of the classical Bowen-York and conformal Kerr extrinsic curvatures. The solution leading to the largest intrinsic spin, relative to the ADM mass of the spacetime epsilon_S=S/M^2_{ADM}, is a superposition with relative weights of Lambda=0.783 for conformal Kerr and (1-Lambda)=0.217 for Bowen-York. In addition, we measure the spin relative to the initial horizon mass M_{H_0}, and find that the quantity chi=S/M_{H_0}^2 reaches a maximum of \chi^{max}=0.9856 for Lambda=0.753. After equilibration, the final black-hole spin should lie in the interval 0.9324<chi_{final}<0.9856. We perform full numerical evolutions to compute the energy radiated and the final horizon mass and spin. We find that the black hole settles to a final spin of chi_{final}^{max}=0.935 when Lambda=0.783. We also study the evolution of the apparent horizon structure of this "maximal" black hole in detail.
|
2406.14603
|
Marc Schneider
|
Francesco Del Porro, Stefano Liberati, Marc Schneider
|
Tunneling method for Hawking quanta in analogue gravity
|
20 pages, 12 figures -- submitted to the special issue of Comptes
Rendus Physique in memory of Renaud Parentani
| null | null | null |
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Analogue Hawking radiation from acoustic horizons is now a well-established
phenomenon, both theoretically and experimentally. Its persistence, despite the
modified dispersion relations characterising analogue models, has been crucial
in advancing our understanding of the robustness of this phenomenon against
ultraviolet modifications of our spacetime description. However, previous
theoretical approaches, such as the Bogoliubov transformation relating
asymptotic states, have somewhat lacked a straightforward physical intuition
regarding the origin of this robustness and its limits of applicability. To
address this, we revisit analogue Hawking radiation using the tunneling method.
We present a unified treatment that allows us to consider flows with and
without acoustic horizons and with superluminal or subluminal dispersion
relations. This approach clarifies the fundamental mechanism behind the
resilience of Hawking radiation in these settings and explains the puzzling
occurrence of excitations even in subcritical (supercritical) flows with
subluminal (superluminal) dispersion relations.
|
[
{
"created": "Thu, 20 Jun 2024 18:00:00 GMT",
"version": "v1"
}
] |
2024-06-24
|
[
[
"Del Porro",
"Francesco",
""
],
[
"Liberati",
"Stefano",
""
],
[
"Schneider",
"Marc",
""
]
] |
Analogue Hawking radiation from acoustic horizons is now a well-established phenomenon, both theoretically and experimentally. Its persistence, despite the modified dispersion relations characterising analogue models, has been crucial in advancing our understanding of the robustness of this phenomenon against ultraviolet modifications of our spacetime description. However, previous theoretical approaches, such as the Bogoliubov transformation relating asymptotic states, have somewhat lacked a straightforward physical intuition regarding the origin of this robustness and its limits of applicability. To address this, we revisit analogue Hawking radiation using the tunneling method. We present a unified treatment that allows us to consider flows with and without acoustic horizons and with superluminal or subluminal dispersion relations. This approach clarifies the fundamental mechanism behind the resilience of Hawking radiation in these settings and explains the puzzling occurrence of excitations even in subcritical (supercritical) flows with subluminal (superluminal) dispersion relations.
|
gr-qc/9805072
|
Jerome Martin
|
Jerome Martin and Dominik J. Schwarz
|
Amplitude of superhorizon cosmological perturbations
|
Contributions to the XXXIIIrd Rencontres de Moriond, Fundamental
Parameters in Cosmology, 5 pages, Latex
| null | null | null |
gr-qc astro-ph
| null |
We study the influence of reheating on super-horizon density perturbations
and gravitational waves. We correct wrong claims [L. P. Grishchuk Phys. Rev. D
50, 7154 (1994) and gr-qc/9801011] about the joining of perturbations at
cosmological transitions and about the quantization of cosmological
perturbations.
|
[
{
"created": "Tue, 19 May 1998 09:15:09 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Martin",
"Jerome",
""
],
[
"Schwarz",
"Dominik J.",
""
]
] |
We study the influence of reheating on super-horizon density perturbations and gravitational waves. We correct wrong claims [L. P. Grishchuk Phys. Rev. D 50, 7154 (1994) and gr-qc/9801011] about the joining of perturbations at cosmological transitions and about the quantization of cosmological perturbations.
|
gr-qc/0403081
|
Luca Lusanna
|
L.Lusanna (INFN, Firenze) and M.Pauri (Parma Univ.)
|
The Physical Role of Gravitational and Gauge Degrees of Freedom in
General Relativity - I: Dynamical Synchronization and Generalized Inertial
Effects
|
45 pages, Revtex4, some refinements added
|
Gen.Rel.Grav.38:187-227,2006
|
10.1007/s10714-005-0217-6
| null |
gr-qc
| null |
This is the first of a couple of papers in which, by exploiting the
capabilities of the Hamiltonian approach to general relativity, we get a number
of technical achievements that are instrumental both for a disclosure of
\emph{new} results concerning specific issues, and for new insights about
\emph{old} foundational problems of the theory. The first paper includes: 1) a
critical analysis of the various concepts of symmetry related to the
Einstein-Hilbert Lagrangian viewpoint on the one hand, and to the Hamiltonian
viewpoint, on the other. This analysis leads, in particular, to a
re-interpretation of {\it active} diffeomorphisms as {\it passive and
metric-dependent} dynamical symmetries of Einstein's equations, a
re-interpretation which enables to disclose the (nearly unknown) connection of
a subgroup of them to Hamiltonian gauge transformations {\it on-shell}; 2) a
re-visitation of the canonical reduction of the ADM formulation of general
relativity, with particular emphasis on the geometro-dynamical effects of the
gauge-fixing procedure, which amounts to the definition of a \emph{global
(non-inertial) space-time laboratory}. This analysis discloses the peculiar
\emph{dynamical nature} that the traditional definition of distant simultaneity
and clock-synchronization assume in general relativity, as well as the {\it
gauge relatedness} of the "conventions" which generalize the classical
Einstein's convention.
|
[
{
"created": "Thu, 18 Mar 2004 10:29:25 GMT",
"version": "v1"
},
{
"created": "Thu, 1 Jul 2004 15:49:55 GMT",
"version": "v2"
}
] |
2014-11-17
|
[
[
"Lusanna",
"L.",
"",
"INFN, Firenze"
],
[
"Pauri",
"M.",
"",
"Parma Univ."
]
] |
This is the first of a couple of papers in which, by exploiting the capabilities of the Hamiltonian approach to general relativity, we get a number of technical achievements that are instrumental both for a disclosure of \emph{new} results concerning specific issues, and for new insights about \emph{old} foundational problems of the theory. The first paper includes: 1) a critical analysis of the various concepts of symmetry related to the Einstein-Hilbert Lagrangian viewpoint on the one hand, and to the Hamiltonian viewpoint, on the other. This analysis leads, in particular, to a re-interpretation of {\it active} diffeomorphisms as {\it passive and metric-dependent} dynamical symmetries of Einstein's equations, a re-interpretation which enables to disclose the (nearly unknown) connection of a subgroup of them to Hamiltonian gauge transformations {\it on-shell}; 2) a re-visitation of the canonical reduction of the ADM formulation of general relativity, with particular emphasis on the geometro-dynamical effects of the gauge-fixing procedure, which amounts to the definition of a \emph{global (non-inertial) space-time laboratory}. This analysis discloses the peculiar \emph{dynamical nature} that the traditional definition of distant simultaneity and clock-synchronization assume in general relativity, as well as the {\it gauge relatedness} of the "conventions" which generalize the classical Einstein's convention.
|
gr-qc/0012103
|
Valdir B. Bezerra
|
J. Spinelly (UFPb), E. R. Bezerra de Mello (UFPb) and V. B.
Bezerra(UFPb)
|
Relativistic Quantum Scattering on a Cone
|
22 pages, LATEX file
| null |
10.1088/0264-9381/18/8/311
| null |
gr-qc
| null |
We study the relativistic quantum mechanical scattering of a bosonic particle
by an infinite straight cosmic string, considering the non-minimal coupling
between the bosonic field and the scalar curvature. In this case, an effective
two-dimensional delta-function interaction takes place besides the usual
topological scattering and a renormalization procedure is necessary in order to
treat the problem that appears in connection with the delta-function.
|
[
{
"created": "Thu, 28 Dec 2000 12:58:15 GMT",
"version": "v1"
}
] |
2009-10-31
|
[
[
"Spinelly",
"J.",
"",
"UFPb"
],
[
"de Mello",
"E. R. Bezerra",
"",
"UFPb"
],
[
"Bezerra",
"V. B.",
"",
"UFPb"
]
] |
We study the relativistic quantum mechanical scattering of a bosonic particle by an infinite straight cosmic string, considering the non-minimal coupling between the bosonic field and the scalar curvature. In this case, an effective two-dimensional delta-function interaction takes place besides the usual topological scattering and a renormalization procedure is necessary in order to treat the problem that appears in connection with the delta-function.
|
gr-qc/0207033
|
R. Michael Jones
|
R. Michael Jones
|
The criteria for a solution of the field equations to be a classical
limit of a quantum cosmology
|
4 pages, submitted to Astronomische Nachrichten
| null | null | null |
gr-qc
| null |
If the gravitational field is quantized, then a solution of Einstein's field
equations is a valid cosmological model only if it corresponds to a classical
limit of a quantum cosmology. To determine which solutions are valid requires
looking at quantum cosmology in a particular way. Because we infer the geometry
by measurements on matter, we can represent the amplitude for any measurement
in terms of the amplitude for the matter fields, allowing us to integrate out
the gravitational degrees of freedom. Combining that result with a
path-integral representation for quantum cosmology leads to an integration over
4-geometries. Even when a semiclassical approximation for the propagator is
valid, the amplitude for any measurement includes an integral over the
gravitational degrees of freedom. The conditions for a solution of the field
equations to be a classical limit of a quantum cosmology are: (1) The effect of
the classical action dominates the integration, (2) the action is stationary
with respect to variation of the gravitational degrees of freedom, and (3) only
one saddlepoint contributes significantly to each integration.
|
[
{
"created": "Fri, 5 Jul 2002 19:29:11 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Jones",
"R. Michael",
""
]
] |
If the gravitational field is quantized, then a solution of Einstein's field equations is a valid cosmological model only if it corresponds to a classical limit of a quantum cosmology. To determine which solutions are valid requires looking at quantum cosmology in a particular way. Because we infer the geometry by measurements on matter, we can represent the amplitude for any measurement in terms of the amplitude for the matter fields, allowing us to integrate out the gravitational degrees of freedom. Combining that result with a path-integral representation for quantum cosmology leads to an integration over 4-geometries. Even when a semiclassical approximation for the propagator is valid, the amplitude for any measurement includes an integral over the gravitational degrees of freedom. The conditions for a solution of the field equations to be a classical limit of a quantum cosmology are: (1) The effect of the classical action dominates the integration, (2) the action is stationary with respect to variation of the gravitational degrees of freedom, and (3) only one saddlepoint contributes significantly to each integration.
|
2209.04025
|
R. E. Kastner
|
A. Schlatter and R. E. Kastner
|
Gravity from Transactions: Fulfilling the Entropic Gravity Program
|
Final accepted version, Journal of Physics Communications (2023)
| null |
10.1088/2399-6528/acd6d7
| null |
gr-qc physics.hist-ph quant-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
This is a review of new developments in entropic gravity in light of the
Relativistic Transactional Interpretation (RTI). A transactional approach to
spacetime events can give rise in a natural way to entropic gravity (in the way
originally proposed by Erik Verlinde) while also overcoming extant objections
to that research program. The theory also naturally gives rise to a
Cosmological Constant and to Modified Newtonian Dynamics (MOND) and thus
provides a physical explanation for the phenomena historically attributed to
"dark energy" and "dark matter".
|
[
{
"created": "Thu, 8 Sep 2022 20:32:26 GMT",
"version": "v1"
},
{
"created": "Wed, 14 Jun 2023 00:52:32 GMT",
"version": "v2"
}
] |
2023-06-16
|
[
[
"Schlatter",
"A.",
""
],
[
"Kastner",
"R. E.",
""
]
] |
This is a review of new developments in entropic gravity in light of the Relativistic Transactional Interpretation (RTI). A transactional approach to spacetime events can give rise in a natural way to entropic gravity (in the way originally proposed by Erik Verlinde) while also overcoming extant objections to that research program. The theory also naturally gives rise to a Cosmological Constant and to Modified Newtonian Dynamics (MOND) and thus provides a physical explanation for the phenomena historically attributed to "dark energy" and "dark matter".
|
1007.5387
|
Ryan Hamerly
|
Ryan Hamerly and Yanbei Chen
|
Event Horizon Deformations in Extreme Mass-Ratio Black Hole Mergers
|
23 pages, 14 figures
|
Phys. Rev. D 84, 124015 (2011)
|
10.1103/PhysRevD.84.124015
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We study the geometry of the event horizon of a spacetime in which a small
compact object plunges into a large Schwarzschild black hole. We first use the
Regge-Wheeler and Zerilli formalisms to calculate the metric perturbations
induced by this small compact object, then find the new event horizon by
propagating null geodesics near the unperturbed horizon. A caustic is shown to
exist before the merger. Focusing on the geometry near the caustic, we show
that it is determined predominantly by large-l perturbations, which in turn
have simple asymptotic forms near the point at which the particle plunges into
the horizon. It is therefore possible to obtain an analytic characterization of
the geometry that is independent of the details of the plunge. We compute the
invariant length of the caustic. We further show that among the leading-order
horizon area increase, half arises from generators that enter the horizon
through the caustic, and the rest arises from area increase near the caustic,
induced by the gravitational field of the compact object.
|
[
{
"created": "Fri, 30 Jul 2010 08:17:41 GMT",
"version": "v1"
},
{
"created": "Thu, 8 Dec 2011 09:00:38 GMT",
"version": "v2"
}
] |
2011-12-09
|
[
[
"Hamerly",
"Ryan",
""
],
[
"Chen",
"Yanbei",
""
]
] |
We study the geometry of the event horizon of a spacetime in which a small compact object plunges into a large Schwarzschild black hole. We first use the Regge-Wheeler and Zerilli formalisms to calculate the metric perturbations induced by this small compact object, then find the new event horizon by propagating null geodesics near the unperturbed horizon. A caustic is shown to exist before the merger. Focusing on the geometry near the caustic, we show that it is determined predominantly by large-l perturbations, which in turn have simple asymptotic forms near the point at which the particle plunges into the horizon. It is therefore possible to obtain an analytic characterization of the geometry that is independent of the details of the plunge. We compute the invariant length of the caustic. We further show that among the leading-order horizon area increase, half arises from generators that enter the horizon through the caustic, and the rest arises from area increase near the caustic, induced by the gravitational field of the compact object.
|
1804.07872
|
Kiyoshi Shiraishi
|
Kiyoshi Shiraishi and Takuya Maki
|
Quantum fluctuation of stress tensor and black holes in three dimensions
|
18 pages, 12 figures
|
Physical Review D49, No. 10, pp. 5286-5294, 15 May 1994
|
10.1103/PhysRevD.49.5286
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The quantum stress tensor near a three-dimensional black hole is studied for
a conformally coupled scalar field. The back reaction to the metric is also
investigated.
|
[
{
"created": "Sat, 21 Apr 2018 00:50:36 GMT",
"version": "v1"
}
] |
2018-05-02
|
[
[
"Shiraishi",
"Kiyoshi",
""
],
[
"Maki",
"Takuya",
""
]
] |
The quantum stress tensor near a three-dimensional black hole is studied for a conformally coupled scalar field. The back reaction to the metric is also investigated.
|
gr-qc/9410045
|
Sardanashvily Gennadi
|
G.Sardanashvily
|
Gauge Gravitation Theory. What is the Geometry of the World?
|
16 pp., compuscript LaTeX, report TP\94\213
| null | null | null |
gr-qc hep-th
| null |
When joined the unified gauge picture of fundamental interactions, the
gravitation theory leads to geometry of a space-time which is far from
simplicity of pseudo-Riemannian geometry of Einstein's General Relativity. This
is geometry of the affine-metric composite dislocated manifolds. The goal is
modification of the familiar equations of a gravitational field and entirely
the new equations of its deviations. In the present brief, we do not detail the
mathematics, but discuss the reasons why it is just this geometry. The major
physical underlying reason lies in spontaneous symmetry breaking when the
fermion matter admits only the Lorentz subgroup of world symmetries of the
geometric arena.
|
[
{
"created": "Sun, 30 Oct 1994 02:49:47 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Sardanashvily",
"G.",
""
]
] |
When joined the unified gauge picture of fundamental interactions, the gravitation theory leads to geometry of a space-time which is far from simplicity of pseudo-Riemannian geometry of Einstein's General Relativity. This is geometry of the affine-metric composite dislocated manifolds. The goal is modification of the familiar equations of a gravitational field and entirely the new equations of its deviations. In the present brief, we do not detail the mathematics, but discuss the reasons why it is just this geometry. The major physical underlying reason lies in spontaneous symmetry breaking when the fermion matter admits only the Lorentz subgroup of world symmetries of the geometric arena.
|
1609.07992
|
Christine Farrugia
|
Christine R. Farrugia and Joseph Sultana
|
Thermodynamic Geodesics of a Reissner Nordstr\"om Black Hole
|
15 pages, 4 figures
| null |
10.1007/s10714-016-2169-4
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Starting from a Geometrothermodynamics metric for the space of thermodynamic
equilibrium states in the mass representation, we use numerical techniques to
analyse the thermodynamic geodesics of a supermassive Reissner Nordstr\"{o}m
black hole in isolation. Appropriate constraints are obtained by taking into
account the processes of Hawking radiation and Schwinger pair--production. We
model the black hole in line with the work of Hiscock and Weems. It can be
deduced that the relation which the geodesics establish between the entropy $S$
and electric charge $Q$ of the black hole extremises changes in the black
hole's mass. Indeed, the expression for the entropy of an extremal black hole
is an exact solution to the geodesic equation. We also find that in certain
cases, the geodesics describe the evolution brought about by the constant
emission of Hawking radiation and charged-particle pairs.
|
[
{
"created": "Fri, 23 Sep 2016 11:00:30 GMT",
"version": "v1"
},
{
"created": "Thu, 13 Oct 2016 11:57:17 GMT",
"version": "v2"
}
] |
2016-12-12
|
[
[
"Farrugia",
"Christine R.",
""
],
[
"Sultana",
"Joseph",
""
]
] |
Starting from a Geometrothermodynamics metric for the space of thermodynamic equilibrium states in the mass representation, we use numerical techniques to analyse the thermodynamic geodesics of a supermassive Reissner Nordstr\"{o}m black hole in isolation. Appropriate constraints are obtained by taking into account the processes of Hawking radiation and Schwinger pair--production. We model the black hole in line with the work of Hiscock and Weems. It can be deduced that the relation which the geodesics establish between the entropy $S$ and electric charge $Q$ of the black hole extremises changes in the black hole's mass. Indeed, the expression for the entropy of an extremal black hole is an exact solution to the geodesic equation. We also find that in certain cases, the geodesics describe the evolution brought about by the constant emission of Hawking radiation and charged-particle pairs.
|
1307.5098
|
David Garfinkle
|
Lydia Bieri and David Garfinkle
|
An electromagnetic analog of gravitational wave memory
| null | null |
10.1088/0264-9381/30/19/195009
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We present an electromagnetic analog of gravitational wave memory. That is,
we consider what change has occurred to a detector of electromagnetic radiation
after the wave has passed. Rather than a distortion in the detector, as occurs
in the gravitational wave case, we find a residual velocity (a "kick") to the
charges in the detector. In analogy with the two types of gravitational wave
memory ("ordinary" and "nonlinear") we find two types of electromagnetic kick.
|
[
{
"created": "Thu, 18 Jul 2013 23:21:22 GMT",
"version": "v1"
},
{
"created": "Tue, 10 Sep 2013 21:06:16 GMT",
"version": "v2"
}
] |
2015-06-16
|
[
[
"Bieri",
"Lydia",
""
],
[
"Garfinkle",
"David",
""
]
] |
We present an electromagnetic analog of gravitational wave memory. That is, we consider what change has occurred to a detector of electromagnetic radiation after the wave has passed. Rather than a distortion in the detector, as occurs in the gravitational wave case, we find a residual velocity (a "kick") to the charges in the detector. In analogy with the two types of gravitational wave memory ("ordinary" and "nonlinear") we find two types of electromagnetic kick.
|
gr-qc/0212011
|
Tae Hoon Lee
|
T. H. Lee, B. H. J. McKellar
|
Neutrino Clustering in the Galaxy with a Global Monopole
|
8 pages, Revtex4
|
Phys.Rev. D67 (2003) 103007
|
10.1103/PhysRevD.67.103007
| null |
gr-qc
| null |
In spherically symmetric, static spacetime, we show that only j=1/2 fermions
can satisfy both Einstein's field equation and Dirac's equation. It is also
shown that neutrinos are able to have effective masses and cluster in the
galactic halo when they are coupled to a global monopole situated at the
galactic core. Astronomical implications of the results are discussed.
|
[
{
"created": "Tue, 3 Dec 2002 02:57:00 GMT",
"version": "v1"
}
] |
2009-11-07
|
[
[
"Lee",
"T. H.",
""
],
[
"McKellar",
"B. H. J.",
""
]
] |
In spherically symmetric, static spacetime, we show that only j=1/2 fermions can satisfy both Einstein's field equation and Dirac's equation. It is also shown that neutrinos are able to have effective masses and cluster in the galactic halo when they are coupled to a global monopole situated at the galactic core. Astronomical implications of the results are discussed.
|
2109.14183
|
Dah-Wei Chiou
|
Bo-Hung Chen and Dah-Wei Chiou
|
Response of the Unruh-DeWitt detector in a gravitational wave background
|
32 pages, 2 figures; contains some of the same material in
arXiv:1605.06656; v2: various minor improvements made, version to appear in
PRD
|
Phys. Rev. D 105, 024053 (2022)
|
10.1103/PhysRevD.105.024053
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Applying the techniques of light-front quantization to quantize a scalar
field in a monochromatic gravitational wave background, we manage to
investigate the response of the Unruh-DeWitt detector coupled to a scalar field
in the presence of a gravitational wave for the two cases moving along a
free-falling trajectory and a constant-accelerating trajectory. The transition
rate of the Unruh-DeWitt detector, in both cases, is different from the result
with no gravitational wave, and the leading-order correction due to the
gravitational wave survives the long-wavelength limit that formally takes the
wavelength of the gravitational wave to infinity. This new effect of the
gravitational wave on a quantum system is qualitatively different from that on
a classical mechanical system, and cannot be understood in terms of
gravitational wave tidal force.
|
[
{
"created": "Wed, 29 Sep 2021 03:58:10 GMT",
"version": "v1"
},
{
"created": "Sat, 22 Jan 2022 06:14:27 GMT",
"version": "v2"
}
] |
2022-02-03
|
[
[
"Chen",
"Bo-Hung",
""
],
[
"Chiou",
"Dah-Wei",
""
]
] |
Applying the techniques of light-front quantization to quantize a scalar field in a monochromatic gravitational wave background, we manage to investigate the response of the Unruh-DeWitt detector coupled to a scalar field in the presence of a gravitational wave for the two cases moving along a free-falling trajectory and a constant-accelerating trajectory. The transition rate of the Unruh-DeWitt detector, in both cases, is different from the result with no gravitational wave, and the leading-order correction due to the gravitational wave survives the long-wavelength limit that formally takes the wavelength of the gravitational wave to infinity. This new effect of the gravitational wave on a quantum system is qualitatively different from that on a classical mechanical system, and cannot be understood in terms of gravitational wave tidal force.
|
1111.5819
|
Sarah Gossan
|
S. Gossan, J. Veitch, B. S. Sathyaprakash
|
Bayesian model selection for testing the no-hair theorem with black hole
ringdowns
|
9 pages, 5 figures
| null |
10.1103/PhysRevD.85.124056
| null |
gr-qc astro-ph.CO
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
General relativity predicts that a black hole that results from the merger of
two compact stars (either black holes or neutron stars) is initially highly
deformed but soon settles down to a quiescent state by emitting a superposition
of quasi-normal modes (QNMs). The QNMs are damped sinusoids with characteristic
frequencies and decay times that depend only on the mass and spin of the black
hole and no other parameter - a statement of the no-hair theorem. In this paper
we have examined the extent to which QNMs could be used to test the no-hair
theorem with future ground- and space-based gravitational-wave detectors. We
model departures from general relativity (GR) by introducing extra parameters
which change the mode frequencies or decay times from their general
relativistic values. With the aid of numerical simulations and Bayesian model
selection, we assess the extent to which the presence of such a parameter could
be inferred, and its value estimated. We find that it is harder to decipher the
departure of decay times from their GR value than it is with the mode
frequencies. Einstein Telescope (ET, a third generation ground-based detector)
could detect departures of <1% in the frequency of the dominant QNM mode of a
500 Msun black hole, out to a maximum range of 4 Gpc. In contrast, the New
Gravitational Observatory (NGO, an ESA space mission to detect gravitational
waves) can detect departures of ~ 0.1% in a 10^8 Msun black hole to a
luminosity distance of 30 Gpc (z = 3.5).
|
[
{
"created": "Thu, 24 Nov 2011 17:24:54 GMT",
"version": "v1"
},
{
"created": "Sat, 26 May 2012 13:37:13 GMT",
"version": "v2"
}
] |
2015-03-19
|
[
[
"Gossan",
"S.",
""
],
[
"Veitch",
"J.",
""
],
[
"Sathyaprakash",
"B. S.",
""
]
] |
General relativity predicts that a black hole that results from the merger of two compact stars (either black holes or neutron stars) is initially highly deformed but soon settles down to a quiescent state by emitting a superposition of quasi-normal modes (QNMs). The QNMs are damped sinusoids with characteristic frequencies and decay times that depend only on the mass and spin of the black hole and no other parameter - a statement of the no-hair theorem. In this paper we have examined the extent to which QNMs could be used to test the no-hair theorem with future ground- and space-based gravitational-wave detectors. We model departures from general relativity (GR) by introducing extra parameters which change the mode frequencies or decay times from their general relativistic values. With the aid of numerical simulations and Bayesian model selection, we assess the extent to which the presence of such a parameter could be inferred, and its value estimated. We find that it is harder to decipher the departure of decay times from their GR value than it is with the mode frequencies. Einstein Telescope (ET, a third generation ground-based detector) could detect departures of <1% in the frequency of the dominant QNM mode of a 500 Msun black hole, out to a maximum range of 4 Gpc. In contrast, the New Gravitational Observatory (NGO, an ESA space mission to detect gravitational waves) can detect departures of ~ 0.1% in a 10^8 Msun black hole to a luminosity distance of 30 Gpc (z = 3.5).
|
1504.02645
|
Tiberiu Harko
|
Shi-Dong Liang, Tiberiu Harko
|
Superconducting dark energy
|
18 pages, 16 figures, accepted for publication in PRD
|
Phys. Rev. D 91, 085042, 2015
|
10.1103/PhysRevD.91.085042
| null |
gr-qc astro-ph.CO hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Based on the analogy with superconductor physics we consider a
scalar-vector-tensor gravitational model, in which the dark energy action is
described by a gauge invariant electromagnetic type functional. By assuming
that the ground state of the dark energy is in a form of a condensate with the
U(1) symmetry spontaneously broken, the gauge invariant electromagnetic dark
energy can be described in terms of the combination of a vector and of a scalar
field (corresponding to the Goldstone boson), respectively. The gravitational
field equations are obtained by also assuming the possibility of a non-minimal
coupling between the cosmological mass current and the superconducting dark
energy. The cosmological implications of the dark energy model are investigated
for a Friedmann-Robertson-Walker homogeneous and isotropic geometry for two
particular choices of the electromagnetic type potential, corresponding to a
pure electric type field, and to a pure magnetic field, respectively. The time
evolution of the scale factor, matter energy density and deceleration parameter
are obtained for both cases, and it is shown that in the presence of the
superconducting dark energy the Universe ends its evolution in an exponentially
accelerating vacuum de Sitter state. By using the formalism of the irreversible
thermodynamic processes for open systems we interpret the generalized
conservation equations in the superconducting dark energy model as describing
matter creation. The particle production rates, the creation pressure and the
entropy evolution are explicitly obtained.
|
[
{
"created": "Fri, 10 Apr 2015 11:56:46 GMT",
"version": "v1"
}
] |
2015-06-24
|
[
[
"Liang",
"Shi-Dong",
""
],
[
"Harko",
"Tiberiu",
""
]
] |
Based on the analogy with superconductor physics we consider a scalar-vector-tensor gravitational model, in which the dark energy action is described by a gauge invariant electromagnetic type functional. By assuming that the ground state of the dark energy is in a form of a condensate with the U(1) symmetry spontaneously broken, the gauge invariant electromagnetic dark energy can be described in terms of the combination of a vector and of a scalar field (corresponding to the Goldstone boson), respectively. The gravitational field equations are obtained by also assuming the possibility of a non-minimal coupling between the cosmological mass current and the superconducting dark energy. The cosmological implications of the dark energy model are investigated for a Friedmann-Robertson-Walker homogeneous and isotropic geometry for two particular choices of the electromagnetic type potential, corresponding to a pure electric type field, and to a pure magnetic field, respectively. The time evolution of the scale factor, matter energy density and deceleration parameter are obtained for both cases, and it is shown that in the presence of the superconducting dark energy the Universe ends its evolution in an exponentially accelerating vacuum de Sitter state. By using the formalism of the irreversible thermodynamic processes for open systems we interpret the generalized conservation equations in the superconducting dark energy model as describing matter creation. The particle production rates, the creation pressure and the entropy evolution are explicitly obtained.
|
0903.4776
|
Leonardo Fernandez-Jambrina
|
L. Fern\'andez-Jambrina
|
Past singularities in phantom theories
|
4 pp. Uses eas.cls. Spanish Relativity Meeting ERE 2007: Relativistic
Astrophysics and Cosmology. Eds: A. Oscoz, E. Mediavilla, M. Serra-Ricart.
EAS Publications Series, Volume 30, EDP Sciences, Les Ulis, 131-136 (2008)
|
Spanish Relativity Meeting ERE 2007: Relativistic Astrophysics and
Cosmology. Eds: A. Oscoz, E. Mediavilla, M. Serra-Ricart. EAS Publications
Series, Volume 30, EDP Sciences, Les Ulis, 131-136 (2008)
| null | null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
FLRW models filled with just dark energy are shown to have a finite past,
since causal geodesics cannot be extended beyond a certain proper time. It is
shown that curvature measured along causal geodesics becomes infinity on
travelling to the past, though curvature scalars tend to zero. Furthermore the
time measured by free-falling observers from coincidence time to Big Rip is
shown to be as short as wished by increasing their linear momentum.
|
[
{
"created": "Fri, 27 Mar 2009 11:41:31 GMT",
"version": "v1"
}
] |
2009-03-31
|
[
[
"Fernández-Jambrina",
"L.",
""
]
] |
FLRW models filled with just dark energy are shown to have a finite past, since causal geodesics cannot be extended beyond a certain proper time. It is shown that curvature measured along causal geodesics becomes infinity on travelling to the past, though curvature scalars tend to zero. Furthermore the time measured by free-falling observers from coincidence time to Big Rip is shown to be as short as wished by increasing their linear momentum.
|
1302.2285
|
Ka\'ca Bradonji\'c
|
John Stachel and Ka\'ca Bradonji\'c
|
Quantum Gravity: Meaning and Measurement
|
24 pages; Minor content additions; fixed typos and references. The
published article can be found at
http://dx.doi.org/10.1016/j.shpsb.2013.12.002
| null |
10.1016/j.shpsb.2013.12.002
| null |
gr-qc physics.hist-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
A discussion of the meaning of a physical concept cannot be separated from
discussion of the conditions for its ideal measurement. We assert that
quantization is no more than the invocation of the quantum of action in the
explanation of some process or phenomenon, and does not imply an assertion of
the fundamental nature of such a process. This leads to an ecumenical approach
to the problem of quantization of the gravitational field. There can be many
valid approaches, each of which should be judged by the domain of its
applicability to various phenomena. If two approaches have overlapping domains,
the relation between them then itself becomes a subject of study. We advocate
an approach to general relativity based on the unimodular group, which
emphasizes the physical significance and measurability of the conformal and
projective structures. A discussion of the method of matched asymptotic
expansions, and of the weakness of terrestrial sources compared with
astrophysical and cosmological sources, leads us to suggest theoretical studies
of gravitational radiation based on retrodiction (observation) rather than
prediction (experimentation).
|
[
{
"created": "Sun, 10 Feb 2013 01:16:17 GMT",
"version": "v1"
},
{
"created": "Sun, 12 Jan 2014 22:44:24 GMT",
"version": "v2"
}
] |
2014-01-14
|
[
[
"Stachel",
"John",
""
],
[
"Bradonjić",
"Kaća",
""
]
] |
A discussion of the meaning of a physical concept cannot be separated from discussion of the conditions for its ideal measurement. We assert that quantization is no more than the invocation of the quantum of action in the explanation of some process or phenomenon, and does not imply an assertion of the fundamental nature of such a process. This leads to an ecumenical approach to the problem of quantization of the gravitational field. There can be many valid approaches, each of which should be judged by the domain of its applicability to various phenomena. If two approaches have overlapping domains, the relation between them then itself becomes a subject of study. We advocate an approach to general relativity based on the unimodular group, which emphasizes the physical significance and measurability of the conformal and projective structures. A discussion of the method of matched asymptotic expansions, and of the weakness of terrestrial sources compared with astrophysical and cosmological sources, leads us to suggest theoretical studies of gravitational radiation based on retrodiction (observation) rather than prediction (experimentation).
|
2210.15367
|
Andrea Orizzonte
|
Andrea Orizzonte
|
Barbero--Immirzi--Holst Lagrangian with Spacetime Barbero--Immirzi
Connections
|
43 pages, 0 figures
| null | null | null |
gr-qc math-ph math.DG math.MP
|
http://creativecommons.org/licenses/by-nc-nd/4.0/
|
We carry out the complete variational analysis of the Barbero--Immirzi--Holst
Lagrangian, which is the Holst Lagrangian expressed in terms of the triad of
fields $(\theta, A, \kappa)$, where $\theta$ is the solder form/spin frame, $A$
is the spacetime Barbero--Immirzi connection, and $\kappa$ is the extrinsic
spacetime field. The Holst Lagrangian depends on the choice of a real, non zero
Holst parameter $\gamma \neq 0$ and constitutes the classical field theory
which is then quantized in Loop Quantum Gravity. The choice of a real Immirzi
parameter $\beta$ sets up a one-to-one correspondence between pairs $(A,
\kappa)$ and spin connections $\omega$ on spacetime. The variation of the
Barbero--Immirzi--Holst Lagrangian is computed for an arbitrary pair of
parameters $(\beta, \gamma)$. We develop and use the calculus of vector-valued
differential forms to improve on the results already present in literature by
better clarifying the geometric character of the resulting Euler--Lagrange
equations. The main result is that the equations for $\theta$ are equivalent to
the vacuum Einstein Field Equations, while the equations for $A$ and $\kappa$
give the same constraint equation for any $\beta \in \mathbb{R}$, namely that
$A + \kappa$ must be the Levi--Civita connection induced by $\theta$. We also
prove that these results are valid for any value of $\gamma \neq 0$, meaning
that the choice of parameters $(\beta, \gamma)$ has no impact on the classical
theory in a vacuum and, in particular, there is no need to set $\beta =
\gamma$.
|
[
{
"created": "Thu, 27 Oct 2022 12:25:25 GMT",
"version": "v1"
}
] |
2022-10-28
|
[
[
"Orizzonte",
"Andrea",
""
]
] |
We carry out the complete variational analysis of the Barbero--Immirzi--Holst Lagrangian, which is the Holst Lagrangian expressed in terms of the triad of fields $(\theta, A, \kappa)$, where $\theta$ is the solder form/spin frame, $A$ is the spacetime Barbero--Immirzi connection, and $\kappa$ is the extrinsic spacetime field. The Holst Lagrangian depends on the choice of a real, non zero Holst parameter $\gamma \neq 0$ and constitutes the classical field theory which is then quantized in Loop Quantum Gravity. The choice of a real Immirzi parameter $\beta$ sets up a one-to-one correspondence between pairs $(A, \kappa)$ and spin connections $\omega$ on spacetime. The variation of the Barbero--Immirzi--Holst Lagrangian is computed for an arbitrary pair of parameters $(\beta, \gamma)$. We develop and use the calculus of vector-valued differential forms to improve on the results already present in literature by better clarifying the geometric character of the resulting Euler--Lagrange equations. The main result is that the equations for $\theta$ are equivalent to the vacuum Einstein Field Equations, while the equations for $A$ and $\kappa$ give the same constraint equation for any $\beta \in \mathbb{R}$, namely that $A + \kappa$ must be the Levi--Civita connection induced by $\theta$. We also prove that these results are valid for any value of $\gamma \neq 0$, meaning that the choice of parameters $(\beta, \gamma)$ has no impact on the classical theory in a vacuum and, in particular, there is no need to set $\beta = \gamma$.
|
gr-qc/0302085
|
Roberto De Pietri
|
Juri Agresti (Firenze Univ.), Roberto De Pietri (Parma Univ. & INFN),
Luca Lusanna (INFN, Firenze), Luca Martucci (Milano Univ. & INFN)
|
Background-Independent Gravitational Waves
|
RevTex4, 4 pages, 4 figures
| null | null | null |
gr-qc astro-ph hep-th
| null |
A Hamiltonian linearization of the rest-frame instant form of tetrad gravity
(gr-qc/0302084), where the Hamiltonian is the weak ADM energy ${\hat E}_{ADM}$,
in a completely fixed (non harmonic) 3-orthogonal Hamiltonian gauge is defined.
For the first time this allows to find an explicit solution of all the
Hamiltonian constraints and an associated linearized solution of Einstein's
equations. It corresponds to background-independent gravitational waves in a
well defined post-Minkowskian Christodoulou-Klainermann space-time.
|
[
{
"created": "Thu, 20 Feb 2003 12:02:39 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Agresti",
"Juri",
"",
"Firenze Univ."
],
[
"De Pietri",
"Roberto",
"",
"Parma Univ. & INFN"
],
[
"Lusanna",
"Luca",
"",
"INFN, Firenze"
],
[
"Martucci",
"Luca",
"",
"Milano Univ. & INFN"
]
] |
A Hamiltonian linearization of the rest-frame instant form of tetrad gravity (gr-qc/0302084), where the Hamiltonian is the weak ADM energy ${\hat E}_{ADM}$, in a completely fixed (non harmonic) 3-orthogonal Hamiltonian gauge is defined. For the first time this allows to find an explicit solution of all the Hamiltonian constraints and an associated linearized solution of Einstein's equations. It corresponds to background-independent gravitational waves in a well defined post-Minkowskian Christodoulou-Klainermann space-time.
|
2212.03285
|
Arina Shtennikova
|
S. Mironov and A. Shtennikova
|
Stable cosmological solutions in Horndeski theory
| null | null |
10.1088/1475-7516/2023/06/037
| null |
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
It is known that the construction of a completely stable solution in
Horndeski theory is restricted very strongly by the so-called no-go theorem.
Previously, various techniques have been used to avoid the conditions of the
theorem. In this paper a new way of constructing stable solutions are shown in
the general Horndeski theory. We considered the situation in which the unitary
gauge studied earlier turns out to be singular. On this basis we construct a
spatially flat, stable bouncing and genesis Universe solutions which are
described by General Relativity with non-conventional scalar field.
|
[
{
"created": "Tue, 6 Dec 2022 19:38:07 GMT",
"version": "v1"
},
{
"created": "Tue, 17 Jan 2023 14:34:15 GMT",
"version": "v2"
},
{
"created": "Wed, 8 Mar 2023 15:36:05 GMT",
"version": "v3"
}
] |
2023-06-23
|
[
[
"Mironov",
"S.",
""
],
[
"Shtennikova",
"A.",
""
]
] |
It is known that the construction of a completely stable solution in Horndeski theory is restricted very strongly by the so-called no-go theorem. Previously, various techniques have been used to avoid the conditions of the theorem. In this paper a new way of constructing stable solutions are shown in the general Horndeski theory. We considered the situation in which the unitary gauge studied earlier turns out to be singular. On this basis we construct a spatially flat, stable bouncing and genesis Universe solutions which are described by General Relativity with non-conventional scalar field.
|
1912.03976
|
Nils Andersson
|
N. Andersson, S. Wells and G.L. Comer
|
A variational approach to relativistic superfluid vortex elasticity
|
29 pages, RevTeX preprint format, 1 figure
| null |
10.1088/1361-6382/ab79d7
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
It is well known that a superfluid rotates by forming an array of quantized
vortices. A relativistic formulation for superfluid vortex dynamics is required
for a range of problems in astrophysics and cosmology, from neutron star
interiors and radio pulsar glitches to possible dark matter condensates on
galactic scales. This paper develops a formalism for such systems, extending
the well-established variational approach to relativistic fluids to account for
the presence of a collection of quantized vortices. The model is firmly
anchored in the geometry of the problem (drawing on aspects from basic string
dynamics) and accounts for elastic aspects associated with a vortex array,
providing a precise foundation for applications which have so far been based on
somewhat ad hoc phenomenology.
|
[
{
"created": "Mon, 9 Dec 2019 11:34:00 GMT",
"version": "v1"
}
] |
2020-06-17
|
[
[
"Andersson",
"N.",
""
],
[
"Wells",
"S.",
""
],
[
"Comer",
"G. L.",
""
]
] |
It is well known that a superfluid rotates by forming an array of quantized vortices. A relativistic formulation for superfluid vortex dynamics is required for a range of problems in astrophysics and cosmology, from neutron star interiors and radio pulsar glitches to possible dark matter condensates on galactic scales. This paper develops a formalism for such systems, extending the well-established variational approach to relativistic fluids to account for the presence of a collection of quantized vortices. The model is firmly anchored in the geometry of the problem (drawing on aspects from basic string dynamics) and accounts for elastic aspects associated with a vortex array, providing a precise foundation for applications which have so far been based on somewhat ad hoc phenomenology.
|
1905.13155
|
Zack Carson
|
Zack Carson, Kent Yagi
|
Multi-band gravitational wave tests of general relativity
|
6 pages, 4 figures; IMR consistency test updates and additional
citations; Updated DECIGO noise curves; Small fixes and style change; Fixed
small issue with Lisa/TianQin bounds on beta
| null |
10.1088/1361-6382/ab5c9a
| null |
gr-qc astro-ph.HE hep-ph hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The violent collisions of black holes provide for excellent test-beds of
Einstein's general relativity in the strong/dynamical gravity regime. We here
demonstrate the resolving power one can gain upon the use of multi-band
observations of gravitational waves from both ground- and space-based
detectors. We find significant improvement in both generic parameterized tests
of general relativity and consistency tests of inspiral-merger-ringdown parts
of the waveform over single-band detections. Such multi-band observations are
crucial for unprecedented probes of e.g. parity-violation in gravity.
|
[
{
"created": "Thu, 30 May 2019 16:19:48 GMT",
"version": "v1"
},
{
"created": "Tue, 4 Jun 2019 19:09:36 GMT",
"version": "v2"
},
{
"created": "Tue, 8 Oct 2019 22:27:09 GMT",
"version": "v3"
},
{
"created": "Tue, 17 Dec 2019 22:27:54 GMT",
"version": "v4"
},
{
"created": "Sat, 22 Aug 2020 20:38:12 GMT",
"version": "v5"
}
] |
2020-08-25
|
[
[
"Carson",
"Zack",
""
],
[
"Yagi",
"Kent",
""
]
] |
The violent collisions of black holes provide for excellent test-beds of Einstein's general relativity in the strong/dynamical gravity regime. We here demonstrate the resolving power one can gain upon the use of multi-band observations of gravitational waves from both ground- and space-based detectors. We find significant improvement in both generic parameterized tests of general relativity and consistency tests of inspiral-merger-ringdown parts of the waveform over single-band detections. Such multi-band observations are crucial for unprecedented probes of e.g. parity-violation in gravity.
|
1101.3765
|
Manuel Tiglio
|
Scott E. Field, Chad R. Galley, Frank Herrmann, Jan S. Hesthaven, Evan
Ochsner, Manuel Tiglio
|
Reduced basis catalogs for gravitational wave templates
|
Minor changes in some of the phrasing to match the version as
published in PRL
|
Phys.Rev.Lett.106:221102,2011
|
10.1103/PhysRevLett.106.221102
| null |
gr-qc astro-ph.IM physics.data-an
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We introduce a reduced basis approach as a new paradigm for modeling,
representing and searching for gravitational waves. We construct waveform
catalogs for non-spinning compact binary coalescences, and we find that for
accuracies of 99% and 99.999% the method generates a factor of about $10-10^5$
fewer templates than standard placement methods. The continuum of gravitational
waves can be represented by a finite and comparatively compact basis. The
method is robust under variations in the noise of detectors, implying that only
a single catalog needs to be generated.
|
[
{
"created": "Wed, 19 Jan 2011 20:09:21 GMT",
"version": "v1"
},
{
"created": "Mon, 13 Jun 2011 19:57:28 GMT",
"version": "v2"
}
] |
2015-03-17
|
[
[
"Field",
"Scott E.",
""
],
[
"Galley",
"Chad R.",
""
],
[
"Herrmann",
"Frank",
""
],
[
"Hesthaven",
"Jan S.",
""
],
[
"Ochsner",
"Evan",
""
],
[
"Tiglio",
"Manuel",
""
]
] |
We introduce a reduced basis approach as a new paradigm for modeling, representing and searching for gravitational waves. We construct waveform catalogs for non-spinning compact binary coalescences, and we find that for accuracies of 99% and 99.999% the method generates a factor of about $10-10^5$ fewer templates than standard placement methods. The continuum of gravitational waves can be represented by a finite and comparatively compact basis. The method is robust under variations in the noise of detectors, implying that only a single catalog needs to be generated.
|
gr-qc/9606051
|
Nikolai V. Mitskievich
|
Nikolai V. Mitskievich (Physics Department, University of Guadalajara,
Guadalajara, Mexico)
|
Relativistic Physics in Arbitrary Reference Frames
|
137 pages, LaTeX type, amssym.def, amssym
| null | null | null |
gr-qc
| null |
In this paper we give a review of the most general approach to description of
reference frames, the monad formalism. This approach is explicitly general
covariant at each step, permitting to use abstract representation of tensor
quantities; it is applicable also to special relativity when non-inertial
effects are considered in its context; moreover, it involves no hypotheses
whatsoever thus being a completely natural one. For the sake of the reader's
convenience, a synopsis of tensor calculus in pseudo-Riemannian space-time
precedes discussion of the subject, containing expressions rarely encountered
in literature but essentially facilitating the consideration. We give also a
comparison of the monad formalism with the other approaches to description of
reference frames in general relativity. In three chapters we consider
applications of the monad formalism to general relativistic mechanics,
electromagnetic and gravitational fields theory. Alongside of the general
theory, which includes the monad representation of basic equations of motion of
(charged) particles and of fields, several concrete solutions are provided to
clarify the physical role and practical application of reference frames (e.g.,
cases when a rotating electrically charged fluid does not produce any electric
field in its co-moving reference frame, or kinematic magnetic charges arise in
a rotating frame). The cases are discussed when it is unnecessary to introduce
a reference frame, and when such an introduction is essential. Special
attention is dedicated to analogy between gravitation, electromagnetism and
mechanics (e.g., the dragging phenomenon and existence in the Maxwell equations
in rotating frames of terms of the same nature as that of the Coriolis and
centrifugal forces).
|
[
{
"created": "Mon, 17 Jun 1996 18:20:36 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Mitskievich",
"Nikolai V.",
"",
"Physics Department, University of Guadalajara,\n Guadalajara, Mexico"
]
] |
In this paper we give a review of the most general approach to description of reference frames, the monad formalism. This approach is explicitly general covariant at each step, permitting to use abstract representation of tensor quantities; it is applicable also to special relativity when non-inertial effects are considered in its context; moreover, it involves no hypotheses whatsoever thus being a completely natural one. For the sake of the reader's convenience, a synopsis of tensor calculus in pseudo-Riemannian space-time precedes discussion of the subject, containing expressions rarely encountered in literature but essentially facilitating the consideration. We give also a comparison of the monad formalism with the other approaches to description of reference frames in general relativity. In three chapters we consider applications of the monad formalism to general relativistic mechanics, electromagnetic and gravitational fields theory. Alongside of the general theory, which includes the monad representation of basic equations of motion of (charged) particles and of fields, several concrete solutions are provided to clarify the physical role and practical application of reference frames (e.g., cases when a rotating electrically charged fluid does not produce any electric field in its co-moving reference frame, or kinematic magnetic charges arise in a rotating frame). The cases are discussed when it is unnecessary to introduce a reference frame, and when such an introduction is essential. Special attention is dedicated to analogy between gravitation, electromagnetism and mechanics (e.g., the dragging phenomenon and existence in the Maxwell equations in rotating frames of terms of the same nature as that of the Coriolis and centrifugal forces).
|
1907.04717
|
David Keitel
|
David Keitel, Graham Woan, Matthew Pitkin, Courtney Schumacher,
Brynley Pearlstone, Keith Riles, Andrew G. Lyne, Jim Palfreyman, Benjamin
Stappers, Patrick Weltevrede
|
First search for long-duration transient gravitational waves after
glitches in the Vela and Crab pulsars
|
10 pages, 3 figures (incl. appendices). Updated to match version
accepted by PRD and fixed a few references
|
Phys. Rev. D 100, 064058 (2019)
|
10.1103/PhysRevD.100.064058
|
LIGO-P1900183
|
gr-qc astro-ph.HE
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Gravitational waves (GWs) can offer a novel window into the structure and
dynamics of neutron stars. Here we present the first search for long-duration
quasi-monochromatic GW transients triggered by pulsar glitches. We focus on two
glitches observed in radio timing of the Vela pulsar (PSR J0835-4510) on 12
December 2016 and the Crab pulsar (PSR J0534+2200) on 27 March 2017, during the
Advanced LIGO second observing run (O2). We assume the GW frequency lies within
a narrow band around twice the spin frequency as known from radio observatons.
Using the fully-coherent transient-enabled F-statistic method to search for
transients of up to four months in length. We find no credible GW candidates
for either target, and through simulated signal injections we set 90% upper
limits on (constant) GW strain as a function of transient duration. For the
larger Vela glitch, we come close to beating an indirect upper limit for when
the total energy liberated in the glitch would be emitted as GWs, thus
demonstrating that similar post-glitch searches at improved detector
sensitivity can soon yield physical constraints on glitch models.
|
[
{
"created": "Wed, 10 Jul 2019 13:38:42 GMT",
"version": "v1"
},
{
"created": "Tue, 10 Sep 2019 15:05:47 GMT",
"version": "v2"
},
{
"created": "Wed, 18 Sep 2019 13:38:32 GMT",
"version": "v3"
}
] |
2019-10-02
|
[
[
"Keitel",
"David",
""
],
[
"Woan",
"Graham",
""
],
[
"Pitkin",
"Matthew",
""
],
[
"Schumacher",
"Courtney",
""
],
[
"Pearlstone",
"Brynley",
""
],
[
"Riles",
"Keith",
""
],
[
"Lyne",
"Andrew G.",
""
],
[
"Palfreyman",
"Jim",
""
],
[
"Stappers",
"Benjamin",
""
],
[
"Weltevrede",
"Patrick",
""
]
] |
Gravitational waves (GWs) can offer a novel window into the structure and dynamics of neutron stars. Here we present the first search for long-duration quasi-monochromatic GW transients triggered by pulsar glitches. We focus on two glitches observed in radio timing of the Vela pulsar (PSR J0835-4510) on 12 December 2016 and the Crab pulsar (PSR J0534+2200) on 27 March 2017, during the Advanced LIGO second observing run (O2). We assume the GW frequency lies within a narrow band around twice the spin frequency as known from radio observatons. Using the fully-coherent transient-enabled F-statistic method to search for transients of up to four months in length. We find no credible GW candidates for either target, and through simulated signal injections we set 90% upper limits on (constant) GW strain as a function of transient duration. For the larger Vela glitch, we come close to beating an indirect upper limit for when the total energy liberated in the glitch would be emitted as GWs, thus demonstrating that similar post-glitch searches at improved detector sensitivity can soon yield physical constraints on glitch models.
|
1605.03212
|
Mariam Bouhmadi-Lopez
|
Mariam Bouhmadi-L\'opez, K. Sravan Kumar, Jo\~ao Marto, Jo\~ao Morais
and Alexander Zhuk
|
$K$-essence model from the mechanical approach point of view: coupled
scalar field and the late cosmic acceleration
|
26 pages, no figures. Conclusions extended and references updated.
Version accepted in JCAP
|
JCAP 07 (2016) 050
|
10.1088/1475-7516/2016/07/050
| null |
gr-qc astro-ph.CO hep-ph hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
In this paper, we consider the Universe at the late stage of its evolution
and deep inside the cell of uniformity. At these scales, we can consider the
Universe to be filled with dust-like matter in the form of discretely
distributed galaxies, a $K$-essence scalar field, playing the role of dark
energy, and radiation as matter sources. We investigate such a Universe in the
mechanical approach. This means that the peculiar velocities of the
inhomogeneities (in the form of galaxies) as well as the fluctuations of the
other perfect fluids are non-relativistic. Such fluids are designated as
coupled because they are concentrated around the inhomogeneities. In the
present paper, we investigate the conditions under which the $K$-essence scalar
field with the most general form for its action can become coupled. We
investigate at the background level three particular examples of the
$K$-essence models: (i) the pure kinetic $K$-essence field, (ii) a $K$-essence
with a constant speed of sound and (iii) the $K$-essence model with the
Lagrangian $bX+cX^2-V(\phi)$. We demonstrate that if the $K$-essence is
coupled, all these $K$-essence models take the form of multicomponent perfect
fluids where one of the component is the cosmological constant. Therefore, they
can provide the late-time cosmic acceleration and be simultaneously compatible
with the mechanical approach.
|
[
{
"created": "Tue, 10 May 2016 20:56:21 GMT",
"version": "v1"
},
{
"created": "Tue, 19 Jul 2016 13:32:03 GMT",
"version": "v2"
}
] |
2016-08-02
|
[
[
"Bouhmadi-López",
"Mariam",
""
],
[
"Kumar",
"K. Sravan",
""
],
[
"Marto",
"João",
""
],
[
"Morais",
"João",
""
],
[
"Zhuk",
"Alexander",
""
]
] |
In this paper, we consider the Universe at the late stage of its evolution and deep inside the cell of uniformity. At these scales, we can consider the Universe to be filled with dust-like matter in the form of discretely distributed galaxies, a $K$-essence scalar field, playing the role of dark energy, and radiation as matter sources. We investigate such a Universe in the mechanical approach. This means that the peculiar velocities of the inhomogeneities (in the form of galaxies) as well as the fluctuations of the other perfect fluids are non-relativistic. Such fluids are designated as coupled because they are concentrated around the inhomogeneities. In the present paper, we investigate the conditions under which the $K$-essence scalar field with the most general form for its action can become coupled. We investigate at the background level three particular examples of the $K$-essence models: (i) the pure kinetic $K$-essence field, (ii) a $K$-essence with a constant speed of sound and (iii) the $K$-essence model with the Lagrangian $bX+cX^2-V(\phi)$. We demonstrate that if the $K$-essence is coupled, all these $K$-essence models take the form of multicomponent perfect fluids where one of the component is the cosmological constant. Therefore, they can provide the late-time cosmic acceleration and be simultaneously compatible with the mechanical approach.
|
gr-qc/0606111
|
Leszek Soko{\l}owski
|
Leszek M. Sokolowski and Andrzej Staruszkiewicz
|
On the issue of gravitons
|
14 pages. One phrase added
|
Class.Quant.Grav. 23 (2006) 5907-5918
|
10.1088/0264-9381/23/20/012
| null |
gr-qc
| null |
We investigate the problem of whether one can anticipate any features of the
graviton without a detailed knowledge of a full quantum gravity. Assuming that
in linearized gravity the graviton is in a sense similar to the photon, we
derive a curious large number coincidence between the number of gravitons
emitted by a solar planet during its orbital period and the number of its
nucleons. In Einstein's GR the analogy between the graviton and the photon is
ill founded. A generic relationship between quanta of a quantum field and plane
waves of the corresponding classical field is broken in the case of GR. The
graviton cannot be classically approximated by a generic pp wave nor by the
exact plane wave. Most important, the ADM energy is a zero frequency
characteristic of any asymptotically flat spacetime and this means that any
general relationship between energy and frequency is a priori impossible. In
particular the formula $E=\hbar \omega$ does not hold. The graviton must have
features different from those of the photon and these cannot be predicted from
classical general relativity.
|
[
{
"created": "Mon, 26 Jun 2006 11:37:38 GMT",
"version": "v1"
},
{
"created": "Fri, 6 Oct 2006 11:46:15 GMT",
"version": "v2"
}
] |
2009-11-11
|
[
[
"Sokolowski",
"Leszek M.",
""
],
[
"Staruszkiewicz",
"Andrzej",
""
]
] |
We investigate the problem of whether one can anticipate any features of the graviton without a detailed knowledge of a full quantum gravity. Assuming that in linearized gravity the graviton is in a sense similar to the photon, we derive a curious large number coincidence between the number of gravitons emitted by a solar planet during its orbital period and the number of its nucleons. In Einstein's GR the analogy between the graviton and the photon is ill founded. A generic relationship between quanta of a quantum field and plane waves of the corresponding classical field is broken in the case of GR. The graviton cannot be classically approximated by a generic pp wave nor by the exact plane wave. Most important, the ADM energy is a zero frequency characteristic of any asymptotically flat spacetime and this means that any general relationship between energy and frequency is a priori impossible. In particular the formula $E=\hbar \omega$ does not hold. The graviton must have features different from those of the photon and these cannot be predicted from classical general relativity.
|
2003.06829
|
Reggie Pantig
|
Reggie C. Pantig, Emmanuel T. Rodulfo
|
Rotating dirty black hole and its shadow
|
14 pages, 23 figures; corrected some typos; added some references;
accepted for publication in Chinese Journal of Physics
|
Chin. J. Phys. (2020)
|
10.1016/j.cjph.2020.08.001
| null |
gr-qc
|
http://creativecommons.org/licenses/by-nc-sa/4.0/
|
In this paper, we examine the effect of dark matter to a Kerr black hole of
mass $m$. The metric is derived using the Newman-Janis algorithm, where the
seed metric originates from the Schwarzschild black hole surrounded by a
spherical shell of dark matter with mass $M$ and thickness $\Delta r_{s}$. The
seed metric is also described in terms of a piecewise mass function with three
different conditions. Specializing in the non-trivial case where the observer
resides inside the dark matter shell, we analyzed how the effective mass of the
black hole environment affects the basic black hole properties. A high
concentration of dark matter near the rotating black hole is needed to have
considerable deviations on the horizons, ergosphere, and photonsphere radius.
The time-like geodesic, however, shows more sensitivity to deviation even at
very low dark matter density. Further, the location of energy extraction via
the Penrose process is also shown to remain unchanged. With how the dark matter
distribution is described in the mass function, and the complexity of how the
shadow radius is defined for a Kerr black hole, deriving an analytic expression
for $\Delta r_{s}$ as a condition for notable dark matter effects to occur
remains inconvenient.
|
[
{
"created": "Sun, 15 Mar 2020 13:33:13 GMT",
"version": "v1"
},
{
"created": "Fri, 20 Mar 2020 02:38:45 GMT",
"version": "v2"
},
{
"created": "Sat, 8 Aug 2020 01:45:51 GMT",
"version": "v3"
}
] |
2020-08-11
|
[
[
"Pantig",
"Reggie C.",
""
],
[
"Rodulfo",
"Emmanuel T.",
""
]
] |
In this paper, we examine the effect of dark matter to a Kerr black hole of mass $m$. The metric is derived using the Newman-Janis algorithm, where the seed metric originates from the Schwarzschild black hole surrounded by a spherical shell of dark matter with mass $M$ and thickness $\Delta r_{s}$. The seed metric is also described in terms of a piecewise mass function with three different conditions. Specializing in the non-trivial case where the observer resides inside the dark matter shell, we analyzed how the effective mass of the black hole environment affects the basic black hole properties. A high concentration of dark matter near the rotating black hole is needed to have considerable deviations on the horizons, ergosphere, and photonsphere radius. The time-like geodesic, however, shows more sensitivity to deviation even at very low dark matter density. Further, the location of energy extraction via the Penrose process is also shown to remain unchanged. With how the dark matter distribution is described in the mass function, and the complexity of how the shadow radius is defined for a Kerr black hole, deriving an analytic expression for $\Delta r_{s}$ as a condition for notable dark matter effects to occur remains inconvenient.
|
gr-qc/9506091
| null |
Franco Buccella, Giampiero Esposito, Gennaro Miele
|
Spontaneously Broken SU(5) Symmetries and One-Loop Effects in the Early
Universe
|
19 pages, plain-tex, published in Classical and Quantum Gravity,
volume 9, pages 1499-1509, year 1992
|
Class.Quant.Grav.9:1499-1509,1992
|
10.1088/0264-9381/9/6/008
|
DSF 91/19
|
gr-qc
| null |
This paper studies one-loop effective potential and
spontaneous-symmetry-breaking pattern for SU(5) gauge theory in de Sitter
space-time. Curvature effects modify the flat-space effective potential by
means of a very complicated special function previously derived in the
literature. An algebraic technique already developed by the first author to
study spontaneous symmetry breaking of SU(n) for renormalizable polynomial
potentials is here generalized, for SU(5), to the much harder case of a de
Sitter background. A detailed algebraic and numerical analysis provides a
better derivation of the stability of the extrema in the maximal subgroups
SU(4) x U(1), SU(3) x SU(2) x U(1), SU(3) x U(1) x U(1) x R(311), SU(2) x SU(2)
x U(1) x U(1) x R(2211), where R(311) and R(2211) discrete symmetries select
particular directions in the corresponding two-dimensional strata. One thus
obtains a deeper understanding of the result, previously found with a different
numerical analysis, predicting the slide of the inflationary universe into
either the SU(3) x SU(2) x U(1) or SU(4) x U(1) extremum. Interestingly, using
this approach, one can easily generalize all previous results to a more
complete SU(5) tree-level potential also containing cubic terms.
|
[
{
"created": "Sat, 1 Jul 1995 20:25:35 GMT",
"version": "v1"
}
] |
2010-04-06
|
[
[
"Buccella",
"Franco",
""
],
[
"Esposito",
"Giampiero",
""
],
[
"Miele",
"Gennaro",
""
]
] |
This paper studies one-loop effective potential and spontaneous-symmetry-breaking pattern for SU(5) gauge theory in de Sitter space-time. Curvature effects modify the flat-space effective potential by means of a very complicated special function previously derived in the literature. An algebraic technique already developed by the first author to study spontaneous symmetry breaking of SU(n) for renormalizable polynomial potentials is here generalized, for SU(5), to the much harder case of a de Sitter background. A detailed algebraic and numerical analysis provides a better derivation of the stability of the extrema in the maximal subgroups SU(4) x U(1), SU(3) x SU(2) x U(1), SU(3) x U(1) x U(1) x R(311), SU(2) x SU(2) x U(1) x U(1) x R(2211), where R(311) and R(2211) discrete symmetries select particular directions in the corresponding two-dimensional strata. One thus obtains a deeper understanding of the result, previously found with a different numerical analysis, predicting the slide of the inflationary universe into either the SU(3) x SU(2) x U(1) or SU(4) x U(1) extremum. Interestingly, using this approach, one can easily generalize all previous results to a more complete SU(5) tree-level potential also containing cubic terms.
|
2112.02121
|
David Brown
|
Isaac Raj Waldstein and J. David Brown
|
Generalized geodesic deviation in de Sitter spacetime
|
9 pages, 6 figures. Final version published in Classical and Quantum
Gravity
|
Classical and Quantum Gravity, Volume 39, Number 11, 2022
|
10.1088/1361-6382/ac6a9e
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The geodesic deviation equation (GDE) describes the tendency of objects to
accelerate towards or away from each other due to spacetime curvature. The GDE
assumes that nearby geodesics have a small rate of separation, which is
formally treated as the same order in smallness as the separation itself. This
assumption is discussed in various papers, but is typically not recognized in
textbooks. Relaxing this assumption leads to the generalized geodesic deviation
equation (GGDE). We demonstrate the distinction between the GDE and the GGDE by
computing the relative acceleration between timelike geodesics in
two-dimensional de Sitter spacetime. We do this by considering a fiducial
geodesic and a secondary geodesic (both timelike) that cross with nonzero
speed. These geodesics are spanned by a spacelike geodesic, whose tangent
evaluated at the fiducial geodesic defines the separation. The second
derivative of the separation describes the relative acceleration between the
fiducial and secondary geodesics. Near the crossing point, where the separation
between the timelike geodesics is small but their rates of separation can be
large, we show that the GGDE holds but the GDE fails to apply.
|
[
{
"created": "Fri, 3 Dec 2021 19:06:31 GMT",
"version": "v1"
},
{
"created": "Sun, 26 Jun 2022 20:11:15 GMT",
"version": "v2"
}
] |
2022-06-28
|
[
[
"Waldstein",
"Isaac Raj",
""
],
[
"Brown",
"J. David",
""
]
] |
The geodesic deviation equation (GDE) describes the tendency of objects to accelerate towards or away from each other due to spacetime curvature. The GDE assumes that nearby geodesics have a small rate of separation, which is formally treated as the same order in smallness as the separation itself. This assumption is discussed in various papers, but is typically not recognized in textbooks. Relaxing this assumption leads to the generalized geodesic deviation equation (GGDE). We demonstrate the distinction between the GDE and the GGDE by computing the relative acceleration between timelike geodesics in two-dimensional de Sitter spacetime. We do this by considering a fiducial geodesic and a secondary geodesic (both timelike) that cross with nonzero speed. These geodesics are spanned by a spacelike geodesic, whose tangent evaluated at the fiducial geodesic defines the separation. The second derivative of the separation describes the relative acceleration between the fiducial and secondary geodesics. Near the crossing point, where the separation between the timelike geodesics is small but their rates of separation can be large, we show that the GGDE holds but the GDE fails to apply.
|
1506.06682
|
Ariel Edery
|
Ariel Edery and Benjamin Constantineau
|
Formation of a condensate during charged collapse
|
21 pages, 10 figures,to appear in CQG. arXiv admin note: text overlap
with arXiv:1203.2279 v2: matches published version in Class. Quantum Grav
|
Class. Quantum Grav. 32 (2015) 165007
|
10.1088/0264-9381/32/16/165007
| null |
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We observe a condensate forming in the interior of a black hole (BH) during
numerical simulations of gravitational collapse of a massless charged (complex)
scalar field. The magnitude of the scalar field in the interior tends to a
non-zero constant; spontaneous breaking of gauge symmetry occurs and a
condensate forms. This phenomena occurs in the presence of a BH without the
standard symmetry breaking quartic potential; the breaking occurs via the
dynamics of the system itself. We also observe that the scalar field in the
interior rotates in the complex plane and show that it matches numerically the
electric potential to within $1\%$. That a charged scalar condensate can form
near the horizon of a black hole in the Abelian Higgs model without the
standard symmetry breaking potential had previously been shown analytically in
an explicit model involving a massive scalar field in an $AdS_4$ background.
Our numerical simulation lends strong support to this finding, although in our
case the scalar field is massless and the spacetime is asymptotically flat.
|
[
{
"created": "Mon, 22 Jun 2015 17:09:59 GMT",
"version": "v1"
},
{
"created": "Thu, 9 Jul 2015 16:17:15 GMT",
"version": "v2"
}
] |
2015-07-28
|
[
[
"Edery",
"Ariel",
""
],
[
"Constantineau",
"Benjamin",
""
]
] |
We observe a condensate forming in the interior of a black hole (BH) during numerical simulations of gravitational collapse of a massless charged (complex) scalar field. The magnitude of the scalar field in the interior tends to a non-zero constant; spontaneous breaking of gauge symmetry occurs and a condensate forms. This phenomena occurs in the presence of a BH without the standard symmetry breaking quartic potential; the breaking occurs via the dynamics of the system itself. We also observe that the scalar field in the interior rotates in the complex plane and show that it matches numerically the electric potential to within $1\%$. That a charged scalar condensate can form near the horizon of a black hole in the Abelian Higgs model without the standard symmetry breaking potential had previously been shown analytically in an explicit model involving a massive scalar field in an $AdS_4$ background. Our numerical simulation lends strong support to this finding, although in our case the scalar field is massless and the spacetime is asymptotically flat.
|
2408.00452
|
Shad Ali
|
Shad Ali, Tong Liu
|
The CR Volume for Black Holes and the Corresponding Entropy Variation: A
Review
|
19 pages, 7 figures, Accepted in Journal of New Astronomy Reviews
|
New Astro. Rev., 101709, 99(2024)
|
10.1016/j.newar.2024.101709
| null |
gr-qc hep-th
|
http://creativecommons.org/licenses/by/4.0/
|
This paper reviews the work done on black hole interior volume, entropy, and
evaporation. An insight into the basics for understanding the interior volume
is presented. A general analogy to investigate the interior volume of a black
hole, the associated quantum mode's entropy, and the evolution relation between
the interior and exterior entropy is explained. Using this analogy, we
predicted the future of information stored in a BH, its radiation, and
evaporation. The results are noted in tables (\ref{tab:1}) and (\ref{tab:2}).
To apply this analogy in BH space-time, we investigated the interior volume,
entropy, and evaluation relation for different types of BHs. Finally, we also
investigated the nature of BH radiation and the probability of particle
emission during the evaporation process.
|
[
{
"created": "Thu, 1 Aug 2024 10:45:37 GMT",
"version": "v1"
}
] |
2024-08-08
|
[
[
"Ali",
"Shad",
""
],
[
"Liu",
"Tong",
""
]
] |
This paper reviews the work done on black hole interior volume, entropy, and evaporation. An insight into the basics for understanding the interior volume is presented. A general analogy to investigate the interior volume of a black hole, the associated quantum mode's entropy, and the evolution relation between the interior and exterior entropy is explained. Using this analogy, we predicted the future of information stored in a BH, its radiation, and evaporation. The results are noted in tables (\ref{tab:1}) and (\ref{tab:2}). To apply this analogy in BH space-time, we investigated the interior volume, entropy, and evaluation relation for different types of BHs. Finally, we also investigated the nature of BH radiation and the probability of particle emission during the evaporation process.
|
2102.11130
|
Martin Bojowald
|
Martin Bojowald
|
Non-covariance of "covariant polymerization" in models of loop quantum
gravity
|
15 pages, v2: new extended example of a bijective canonical
transformation
|
Phys. Rev. D 103, 126025 (2021)
|
10.1103/PhysRevD.103.126025
| null |
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
It is possible to implement a certain form of modified gravity inspired by
loop quantization through non-bijective canonical transformations. The
canonical nature might suggest that such modifications are guaranteed to
preserve general covariance. Here, however, we show that a dedicated space-time
analysis is still required, even in the case of a bijective canonical
transformation. In addition, a complete global analysis is presented for a
recent proposal of a non-bijective transformation, showing that it does not
preserve general covariance and that the only novel physical effect introduced
by the modification is the presence of certain time-reversal hypersurfaces
between classical space-time regions. These results provide further insights
into the physical interpretation of modified dynamics in models of loop quantum
gravity.
|
[
{
"created": "Mon, 22 Feb 2021 15:58:08 GMT",
"version": "v1"
},
{
"created": "Tue, 29 Jun 2021 18:38:02 GMT",
"version": "v2"
}
] |
2021-07-07
|
[
[
"Bojowald",
"Martin",
""
]
] |
It is possible to implement a certain form of modified gravity inspired by loop quantization through non-bijective canonical transformations. The canonical nature might suggest that such modifications are guaranteed to preserve general covariance. Here, however, we show that a dedicated space-time analysis is still required, even in the case of a bijective canonical transformation. In addition, a complete global analysis is presented for a recent proposal of a non-bijective transformation, showing that it does not preserve general covariance and that the only novel physical effect introduced by the modification is the presence of certain time-reversal hypersurfaces between classical space-time regions. These results provide further insights into the physical interpretation of modified dynamics in models of loop quantum gravity.
|
gr-qc/0103088
|
Lorenzo Iorio
|
Lorenzo Iorio, Ignazio Ciufolini, Erricos C. Pavlis
|
Measuring the relativistic perigee advance with Satellite Laser Ranging
|
LaTex2e, 14 pages, no figures, 2 tables. To appear in Classical and
Quantum Gravity
|
Class.Quant.Grav. 19 (2002) 4301-4309
|
10.1088/0264-9381/19/16/306
| null |
gr-qc astro-ph
| null |
One of the most famous classical tests of General Relativity is the
gravitoelectric secular advance of the pericenter of a test body in the
gravitational field of a central mass. In this paper we explore the possibility
of performing a measurement of the gravitoelectric pericenter advance in the
gravitational field of the Earth by analyzing the laser-ranged data to some
existing, or proposed, laser-ranged geodetic satellites. At the present level
of knowledge of various error sources, the relative precision obtainable with
the data from LAGEOS and LAGEOS II, suitably combined, is of the order of
$10^{\rm -3}$. Nevertheless, these accuracies could sensibly be improved in the
near future when the new data on the terrestrial gravitational field from the
CHAMP and GRACE missions will be available. The use of the perigee of LARES
(LAser RElativity Satellite), in the context of a suitable combination of
orbital residuals including also LAGEOS II, should further raise the precision
of the measurement. As a secondary outcome of the proposed experiment, with the
so obtained value of $\ppn$ and with $\et=4\beta-\gamma-3$ from Lunar Laser
Ranging it could be possible to obtain an estimate of the PPN parameters
$\gamma$ and $\beta$ at the $10^{-2}-10^{-3}$ level.
|
[
{
"created": "Fri, 23 Mar 2001 18:02:38 GMT",
"version": "v1"
},
{
"created": "Mon, 1 Jul 2002 15:23:34 GMT",
"version": "v10"
},
{
"created": "Mon, 26 Mar 2001 18:30:29 GMT",
"version": "v2"
},
{
"created": "Tue, 27 Mar 2001 23:00:22 GMT",
"version": "v3"
},
{
"created": "Mon, 5 Nov 2001 00:59:15 GMT",
"version": "v4"
},
{
"created": "Wed, 6 Feb 2002 22:42:07 GMT",
"version": "v5"
},
{
"created": "Thu, 7 Mar 2002 22:28:44 GMT",
"version": "v6"
},
{
"created": "Sat, 30 Mar 2002 11:03:02 GMT",
"version": "v7"
},
{
"created": "Tue, 30 Apr 2002 13:30:01 GMT",
"version": "v8"
},
{
"created": "Thu, 23 May 2002 23:55:41 GMT",
"version": "v9"
}
] |
2007-05-23
|
[
[
"Iorio",
"Lorenzo",
""
],
[
"Ciufolini",
"Ignazio",
""
],
[
"Pavlis",
"Erricos C.",
""
]
] |
One of the most famous classical tests of General Relativity is the gravitoelectric secular advance of the pericenter of a test body in the gravitational field of a central mass. In this paper we explore the possibility of performing a measurement of the gravitoelectric pericenter advance in the gravitational field of the Earth by analyzing the laser-ranged data to some existing, or proposed, laser-ranged geodetic satellites. At the present level of knowledge of various error sources, the relative precision obtainable with the data from LAGEOS and LAGEOS II, suitably combined, is of the order of $10^{\rm -3}$. Nevertheless, these accuracies could sensibly be improved in the near future when the new data on the terrestrial gravitational field from the CHAMP and GRACE missions will be available. The use of the perigee of LARES (LAser RElativity Satellite), in the context of a suitable combination of orbital residuals including also LAGEOS II, should further raise the precision of the measurement. As a secondary outcome of the proposed experiment, with the so obtained value of $\ppn$ and with $\et=4\beta-\gamma-3$ from Lunar Laser Ranging it could be possible to obtain an estimate of the PPN parameters $\gamma$ and $\beta$ at the $10^{-2}-10^{-3}$ level.
|
1206.2263
|
Tae Hoon Lee
|
Joohan Lee, Tae Hoon Lee, and Phillial Oh
|
Conformally-coupled dark spinor and FRW universe
|
4 pages, Revised argument in section III, results unchanged. To be
published in PRD
| null |
10.1103/PhysRevD.86.107301
| null |
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We study conformal coupling of dark spinor fields to gravity and calculate
the energy density and the pressure of the spinor in FRW spacetime. We consider
the renormalizable potential of the spinor field. In the cases where the field
is proportional to some power of the cosmic scale factor $a(t)$, we determine
the Hubble parameter as a function of the scale factor and find analytic
solutions for $a(t)$ when the spinor field matter dilutes as the universe
expands. We discuss the possibility that both matter- and dark energy-dominated
eras of our universe can be described by the dark spinor.
|
[
{
"created": "Mon, 11 Jun 2012 15:40:17 GMT",
"version": "v1"
},
{
"created": "Wed, 5 Sep 2012 13:13:24 GMT",
"version": "v2"
},
{
"created": "Fri, 26 Oct 2012 04:42:51 GMT",
"version": "v3"
}
] |
2013-05-30
|
[
[
"Lee",
"Joohan",
""
],
[
"Lee",
"Tae Hoon",
""
],
[
"Oh",
"Phillial",
""
]
] |
We study conformal coupling of dark spinor fields to gravity and calculate the energy density and the pressure of the spinor in FRW spacetime. We consider the renormalizable potential of the spinor field. In the cases where the field is proportional to some power of the cosmic scale factor $a(t)$, we determine the Hubble parameter as a function of the scale factor and find analytic solutions for $a(t)$ when the spinor field matter dilutes as the universe expands. We discuss the possibility that both matter- and dark energy-dominated eras of our universe can be described by the dark spinor.
|
1309.2187
|
Roger Francis Picken
|
J. E. Nelson and R. F. Picken
|
Theory of intersecting loops on a torus
|
31 pages, 30 figures. Version 2 has an improved text for the
abstract. To appear in Adv. Theor. Math. Phys., Issue 18.3, May-June 2014.
arXiv admin note: text overlap with arXiv:1006.0921
| null | null | null |
gr-qc hep-th math-ph math.MP math.QA
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We continue our investigation into intersections of closed paths on a torus,
to further our understanding of the commutator algebra of Wilson loop
observables in 2+1 quantum gravity, when the cosmological constant is negative.
We give a concise review of previous results, e.g. that signed area phases
relate observables assigned to homotopic loops, and present new developments in
this theory of intersecting loops on a torus. We state precise rules to be
applied at intersections of both straight and crooked/rerouted paths in the
covering space $\mathbb{R}^2$. Two concrete examples of combinations of
different rules are presented.
|
[
{
"created": "Mon, 9 Sep 2013 15:14:46 GMT",
"version": "v1"
},
{
"created": "Thu, 12 Sep 2013 16:46:03 GMT",
"version": "v2"
},
{
"created": "Thu, 10 Apr 2014 14:58:50 GMT",
"version": "v3"
}
] |
2014-04-11
|
[
[
"Nelson",
"J. E.",
""
],
[
"Picken",
"R. F.",
""
]
] |
We continue our investigation into intersections of closed paths on a torus, to further our understanding of the commutator algebra of Wilson loop observables in 2+1 quantum gravity, when the cosmological constant is negative. We give a concise review of previous results, e.g. that signed area phases relate observables assigned to homotopic loops, and present new developments in this theory of intersecting loops on a torus. We state precise rules to be applied at intersections of both straight and crooked/rerouted paths in the covering space $\mathbb{R}^2$. Two concrete examples of combinations of different rules are presented.
|
gr-qc/9209005
|
Tsvi
|
Dalia S. Goldwirth, Malcolm J. Perry and Tsvi Piran
|
The Loss of Unitarity in the Vicinity of a Time Machine
|
13 pages
| null | null | null |
gr-qc hep-th
| null |
We construct the propagator of a non-relativistic non-interacting particle in
a flat spacetime in which two regions have been identified. This corresponds to
the simplest "time machine". We show that while completeness is lost in the
vicinity of the time machine it holds before the time machine appears and it is
recovered afterwards. Unitarity, however, is not satisfied anywhere. We discuss
the implications of these results and their relationship to the loss of
unitarity in black hole evaporation.
|
[
{
"created": "Mon, 14 Sep 1992 19:53:30 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Goldwirth",
"Dalia S.",
""
],
[
"Perry",
"Malcolm J.",
""
],
[
"Piran",
"Tsvi",
""
]
] |
We construct the propagator of a non-relativistic non-interacting particle in a flat spacetime in which two regions have been identified. This corresponds to the simplest "time machine". We show that while completeness is lost in the vicinity of the time machine it holds before the time machine appears and it is recovered afterwards. Unitarity, however, is not satisfied anywhere. We discuss the implications of these results and their relationship to the loss of unitarity in black hole evaporation.
|
gr-qc/9401028
|
Peter Peldan
|
Subenoy Chakraborty and Peter Peldan
|
Towards a unification of gravity and Yang-Mills theory
|
7 pages, CGPG-94/1-3
|
Phys.Rev.Lett.73:1195-1198,1994
|
10.1103/PhysRevLett.73.1195
| null |
gr-qc hep-th
| null |
We introduce a gauge and diffeomorphism invariant theory on Yang-Mills phase
space. The theory is well defined for an arbitrary gauge group with an
invariant bilinear form, it contains only first class constraints, and the
spacetime metric has a simple form in terms of the phase space variables. With
gauge group $SO(3,C)$, the theory equals the Ashtekar formulation of gravity
with a cosmological constant. For Lorentzian signature, the theory is complex,
and we have not found any good reality conditions. In the Euclidean signature
case, everything is real. In a weak field expansion around de Sitter spacetime,
the theory is shown to give the conventional Yang-Mills theory to the lowest
order in the fields.
|
[
{
"created": "Tue, 25 Jan 1994 20:50:10 GMT",
"version": "v1"
}
] |
2010-11-01
|
[
[
"Chakraborty",
"Subenoy",
""
],
[
"Peldan",
"Peter",
""
]
] |
We introduce a gauge and diffeomorphism invariant theory on Yang-Mills phase space. The theory is well defined for an arbitrary gauge group with an invariant bilinear form, it contains only first class constraints, and the spacetime metric has a simple form in terms of the phase space variables. With gauge group $SO(3,C)$, the theory equals the Ashtekar formulation of gravity with a cosmological constant. For Lorentzian signature, the theory is complex, and we have not found any good reality conditions. In the Euclidean signature case, everything is real. In a weak field expansion around de Sitter spacetime, the theory is shown to give the conventional Yang-Mills theory to the lowest order in the fields.
|
gr-qc/9411004
|
Don N. Page
|
Don N. Page (CIAR Cosmology Program, University of Alberta)
|
Probabilities Don't Matter
|
22 pages, LaTeX, references added and other minor changes
| null | null |
Alberta-Thy-28-94
|
gr-qc hep-th quant-ph
| null |
It is suggested that probabilities need not apply at all to matter in the
physical world, which may be entirely described by the amplitudes given by the
quantum mechanical state. Instead, probabilities may apply only to conscious
perceptions in the mental world. Such perceptions may not form unique sequences
that one could call individual minds.
|
[
{
"created": "Tue, 1 Nov 1994 23:41:22 GMT",
"version": "v1"
},
{
"created": "Wed, 2 Nov 1994 18:45:25 GMT",
"version": "v2"
},
{
"created": "Thu, 3 Nov 1994 23:47:08 GMT",
"version": "v3"
},
{
"created": "Sat, 26 Nov 1994 07:42:18 GMT",
"version": "v4"
}
] |
2008-02-03
|
[
[
"Page",
"Don N.",
"",
"CIAR Cosmology Program, University of Alberta"
]
] |
It is suggested that probabilities need not apply at all to matter in the physical world, which may be entirely described by the amplitudes given by the quantum mechanical state. Instead, probabilities may apply only to conscious perceptions in the mental world. Such perceptions may not form unique sequences that one could call individual minds.
|
2212.09375
|
Julio Arrechea
|
Julio Arrechea, Carlos Barcel\'o, Ra\'ul Carballo-Rubio, Luis J. Garay
|
Asymptotically flat vacuum solutions in order-reduced semiclassical
gravity
|
20 pages, 4 figures. v2: Added minor comments and corrected typos to
match published version
| null |
10.1103/PhysRevD.107.085005
| null |
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We investigate the effects of quantum backreaction on the Schwarzschild
geometry in the semiclassical approximation. The renormalized stress-energy
tensor (RSET) of a scalar field is modelled via an order reduction of the
analytical approximation derived by Anderson, Hiscock and Samuel (AHS). As the
resulting AHS semiclassical Einstein equations are of fourth-derivative order
in the metric, we follow a reduction of order prescription to shrink the space
of solutions. Motivated by this prescription, we develop a method that allows
to obtain a novel analytic approximation for the RSET that exhibits all the
desired properties for a well-posed RSET: conservation, regularity, and correct
estimation of vacuum-state contributions. We derive a set of semiclassical
equations sourced by the order-reduced AHS-RSET in the Boulware state. We
classify the self-consistent solutions to this set of field equations, discuss
their main features and address how well they resemble the solutions of the
higher-order semiclassical theory. Finally, we establish a comparison with
previous results in the literature obtained through the Polyakov approximation
for minimally coupled scalar fields.
|
[
{
"created": "Mon, 19 Dec 2022 11:22:48 GMT",
"version": "v1"
},
{
"created": "Tue, 25 Jul 2023 11:29:58 GMT",
"version": "v2"
}
] |
2023-07-26
|
[
[
"Arrechea",
"Julio",
""
],
[
"Barceló",
"Carlos",
""
],
[
"Carballo-Rubio",
"Raúl",
""
],
[
"Garay",
"Luis J.",
""
]
] |
We investigate the effects of quantum backreaction on the Schwarzschild geometry in the semiclassical approximation. The renormalized stress-energy tensor (RSET) of a scalar field is modelled via an order reduction of the analytical approximation derived by Anderson, Hiscock and Samuel (AHS). As the resulting AHS semiclassical Einstein equations are of fourth-derivative order in the metric, we follow a reduction of order prescription to shrink the space of solutions. Motivated by this prescription, we develop a method that allows to obtain a novel analytic approximation for the RSET that exhibits all the desired properties for a well-posed RSET: conservation, regularity, and correct estimation of vacuum-state contributions. We derive a set of semiclassical equations sourced by the order-reduced AHS-RSET in the Boulware state. We classify the self-consistent solutions to this set of field equations, discuss their main features and address how well they resemble the solutions of the higher-order semiclassical theory. Finally, we establish a comparison with previous results in the literature obtained through the Polyakov approximation for minimally coupled scalar fields.
|
2403.13860
|
Abraao Capistrano
|
Abra\~ao J. S. Capistrano, Rafael C. Nunes, Lu\'is A. Cabral
|
Lower tensor-to-scalar ratio as possible signature of modified gravity
|
14 pages, 3 figures, accepted version in PRD
| null |
10.1103/PhysRevD.109.123517
| null |
gr-qc astro-ph.CO
|
http://creativecommons.org/licenses/by/4.0/
|
This paper simplifies the induced four-dimensional gravitational equations
originating from a five-dimensional bulk within the framework of Nash's
embeddings, incorporating them into a well-known $\mu-\Sigma$ modified gravity
(MG) parametrization. By leveraging data from Planck Public Release 4 (PR4),
BICEP/Keck Array 2018, Planck cosmic microwave background lensing, and baryon
acoustic oscillation observations, we establish a stringent lower limit for the
tensor-to-scalar ratio parameter: $r < 0.0303$ at a confidence level (CL) of
95\%. This finding suggests the presence of extrinsic dynamics influencing
standard four-dimensional cosmology. Notably, this limit surpasses those
typically obtained through Bayesian analysis using Markov Chain Monte Carlo
(MCMC) techniques, which yield $r<0.038$, or through the frequentist profile
likelihood method, which yields $r<0.037$ at 95\% CL.
|
[
{
"created": "Tue, 19 Mar 2024 22:55:49 GMT",
"version": "v1"
},
{
"created": "Mon, 10 Jun 2024 18:17:02 GMT",
"version": "v2"
}
] |
2024-06-12
|
[
[
"Capistrano",
"Abraão J. S.",
""
],
[
"Nunes",
"Rafael C.",
""
],
[
"Cabral",
"Luís A.",
""
]
] |
This paper simplifies the induced four-dimensional gravitational equations originating from a five-dimensional bulk within the framework of Nash's embeddings, incorporating them into a well-known $\mu-\Sigma$ modified gravity (MG) parametrization. By leveraging data from Planck Public Release 4 (PR4), BICEP/Keck Array 2018, Planck cosmic microwave background lensing, and baryon acoustic oscillation observations, we establish a stringent lower limit for the tensor-to-scalar ratio parameter: $r < 0.0303$ at a confidence level (CL) of 95\%. This finding suggests the presence of extrinsic dynamics influencing standard four-dimensional cosmology. Notably, this limit surpasses those typically obtained through Bayesian analysis using Markov Chain Monte Carlo (MCMC) techniques, which yield $r<0.038$, or through the frequentist profile likelihood method, which yields $r<0.037$ at 95\% CL.
|
2103.15891
|
Caroline Owen
|
Caroline B. Owen, Nicol\'as Yunes, Helvi Witek
|
Petrov Type, Principal Null Directions, and Killing Tensors of
Slowly-Rotating Black Holes in Quadratic Gravity
|
23 pages, 2 figures, reuploaded on 01/04/24 to correct small typo in
Eq (C5)
|
Phys. Rev. D 103, 124057 (2021)
|
10.1103/PhysRevD.103.124057
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The ability to test general relativity in extreme gravity regimes using
gravitational wave observations from current ground-based or future space-based
detectors motivates the mathematical study of the symmetries of black holes in
modified theories of gravity. In this paper we focus on spinning black hole
solutions in two quadratic gravity theories: dynamical Chern-Simons and scalar
Gauss-Bonnet gravity. We compute the principal null directions, Weyl scalars,
and complex null tetrad in the small-coupling, slow rotation approximation for
both theories, confirming that both spacetimes are Petrov type I. Additionally,
we solve the Killing equation through rank 6 in dynamical Chern-Simons gravity
and rank 2 in scalar Gauss-Bonnet gravity, showing that there is no nontrivial
Killing tensor through those ranks for each theory. We therefore conjecture
that the still-unknown, exact, quadratic-gravity, black-hole solutions do not
possess a fourth constant of motion.
|
[
{
"created": "Mon, 29 Mar 2021 19:00:11 GMT",
"version": "v1"
},
{
"created": "Thu, 15 Jul 2021 19:08:38 GMT",
"version": "v2"
},
{
"created": "Thu, 22 Jul 2021 14:40:48 GMT",
"version": "v3"
},
{
"created": "Fri, 5 Jan 2024 13:16:27 GMT",
"version": "v4"
}
] |
2024-01-08
|
[
[
"Owen",
"Caroline B.",
""
],
[
"Yunes",
"Nicolás",
""
],
[
"Witek",
"Helvi",
""
]
] |
The ability to test general relativity in extreme gravity regimes using gravitational wave observations from current ground-based or future space-based detectors motivates the mathematical study of the symmetries of black holes in modified theories of gravity. In this paper we focus on spinning black hole solutions in two quadratic gravity theories: dynamical Chern-Simons and scalar Gauss-Bonnet gravity. We compute the principal null directions, Weyl scalars, and complex null tetrad in the small-coupling, slow rotation approximation for both theories, confirming that both spacetimes are Petrov type I. Additionally, we solve the Killing equation through rank 6 in dynamical Chern-Simons gravity and rank 2 in scalar Gauss-Bonnet gravity, showing that there is no nontrivial Killing tensor through those ranks for each theory. We therefore conjecture that the still-unknown, exact, quadratic-gravity, black-hole solutions do not possess a fourth constant of motion.
|
1604.00463
|
Tekin Dereli
|
T.Dereli and C.Yetismisoglu
|
New Improved Massive Gravity and Three Dimensional Spacetimes of
Constant Curvature and Constant Torsion
|
16 pages
|
Phys. Rev. D 94, 064067 (2016)
|
10.1103/PhysRevD.94.064067
| null |
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We derive the field equations for topologically massive gravity coupled with
the most general quadratic curvature terms using the language of exterior
differential forms and a first order constrained variational principle. We find
variational field equations both in the presence and absence of torsion. We
then show that spaces of constant negative curvature (i.e. the anti de-Sitter
space $AdS_3$) and constant torsion provide exact solutions.
|
[
{
"created": "Sat, 2 Apr 2016 05:31:35 GMT",
"version": "v1"
},
{
"created": "Mon, 20 Jun 2016 11:20:14 GMT",
"version": "v2"
}
] |
2016-09-28
|
[
[
"Dereli",
"T.",
""
],
[
"Yetismisoglu",
"C.",
""
]
] |
We derive the field equations for topologically massive gravity coupled with the most general quadratic curvature terms using the language of exterior differential forms and a first order constrained variational principle. We find variational field equations both in the presence and absence of torsion. We then show that spaces of constant negative curvature (i.e. the anti de-Sitter space $AdS_3$) and constant torsion provide exact solutions.
|
2307.04739
|
Orlando Luongo
|
Alessio Belfiglio, Youri Carloni, Orlando Luongo
|
Particle production from non-minimal coupling in a symmetry breaking
potential transporting vacuum energy
|
22 pages, 13 figures, 9 tables
|
Phys. Dark Univ., 44, 101458, (2024)
| null | null |
gr-qc astro-ph.CO
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We propose an inflationary scenario where the inflaton field is non-minimally
coupled to spacetime curvature and inflation is driven by a vacuum energy
symmetry breaking potential without specifying \emph{a priori} whether the
inflaton field is small or large. As we incorporate vacuum energy into our
analysis, we further explore the implications of a non-zero potential offset in
relation to the emergence of inflationary dynamics. Thus, we propose that
vacuum energy can transform into particles as a result of the transition
triggered by spontaneous symmetry breaking. This entails a vacuum energy
cancellation that yields an effective cosmological constant during inflation by
virtue of a quasi-de Sitter evolution and shows that the vacuum energy
contribution can manifest as \emph{geometric particles} produced by inflaton
fluctuations, with particular emphasis on super-Hubble modes. We conjecture
these particles as \emph{quasi-particles} arising from interaction between the
inflaton and spacetime geometry, enhanced by non-minimal coupling.
Specifically, we propose that dark matter arises from a pure geometric
quasi-particle contribution, and we quantify the corresponding dark matter
candidate ranges of mass. In this scenario, we further find that a zero
potential offset leads to a bare cosmological constant at the end of inflation,
while a negative offset would require an additional kinetic (or potential)
contribution in order to be fully-canceled. In this regard, we conclude that
the scenario of large field inflaton is preferred since it necessitates a more
appropriate selection of the offset. Our conclusion is reinforced as small
field inflaton would lead to a significant screening of the Newtonian
gravitational constant as inflation ends.
|
[
{
"created": "Mon, 10 Jul 2023 17:52:04 GMT",
"version": "v1"
},
{
"created": "Mon, 3 Jun 2024 17:07:08 GMT",
"version": "v2"
}
] |
2024-06-04
|
[
[
"Belfiglio",
"Alessio",
""
],
[
"Carloni",
"Youri",
""
],
[
"Luongo",
"Orlando",
""
]
] |
We propose an inflationary scenario where the inflaton field is non-minimally coupled to spacetime curvature and inflation is driven by a vacuum energy symmetry breaking potential without specifying \emph{a priori} whether the inflaton field is small or large. As we incorporate vacuum energy into our analysis, we further explore the implications of a non-zero potential offset in relation to the emergence of inflationary dynamics. Thus, we propose that vacuum energy can transform into particles as a result of the transition triggered by spontaneous symmetry breaking. This entails a vacuum energy cancellation that yields an effective cosmological constant during inflation by virtue of a quasi-de Sitter evolution and shows that the vacuum energy contribution can manifest as \emph{geometric particles} produced by inflaton fluctuations, with particular emphasis on super-Hubble modes. We conjecture these particles as \emph{quasi-particles} arising from interaction between the inflaton and spacetime geometry, enhanced by non-minimal coupling. Specifically, we propose that dark matter arises from a pure geometric quasi-particle contribution, and we quantify the corresponding dark matter candidate ranges of mass. In this scenario, we further find that a zero potential offset leads to a bare cosmological constant at the end of inflation, while a negative offset would require an additional kinetic (or potential) contribution in order to be fully-canceled. In this regard, we conclude that the scenario of large field inflaton is preferred since it necessitates a more appropriate selection of the offset. Our conclusion is reinforced as small field inflaton would lead to a significant screening of the Newtonian gravitational constant as inflation ends.
|
1504.04050
|
Ermis Mitsou
|
Ermis Mitsou
|
Aspects of Infrared Non-local Modifications of General Relativity
|
144 pages, 13 figures, Ph.D. thesis
|
Springer Theses (2016)
|
10.1007/978-3-319-31729-8
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
In this thesis we are interested in the problem of dark energy in cosmology.
In particular, we consider the possibility that this effect is due to an
infrared non-local modification of the theory of General Relativity. Inspired
by massive gravity, we construct non-local theories in which gravity may be
massive, but where the symmetry of diffeomorphisms is preserved. We focus on
the cosmology of these theories and confront them with observational
constraints. On a more theoretical level, we discuss some subtleties of
non-local field theory and address in a novel way the issue of stability. This
thesis is based on both published and original work.
|
[
{
"created": "Wed, 15 Apr 2015 21:05:07 GMT",
"version": "v1"
}
] |
2016-04-26
|
[
[
"Mitsou",
"Ermis",
""
]
] |
In this thesis we are interested in the problem of dark energy in cosmology. In particular, we consider the possibility that this effect is due to an infrared non-local modification of the theory of General Relativity. Inspired by massive gravity, we construct non-local theories in which gravity may be massive, but where the symmetry of diffeomorphisms is preserved. We focus on the cosmology of these theories and confront them with observational constraints. On a more theoretical level, we discuss some subtleties of non-local field theory and address in a novel way the issue of stability. This thesis is based on both published and original work.
|
1806.09129
|
Kourosh Nozari
|
Kourosh Nozari, S. Shafizadeh and N. Rashidi
|
Lowering the self-coupling of the scalar field in a generalized Higgs
inflation
|
13 Pages, 4 Figures
|
Astrophys. Space Sci. 363 (2018) 135
|
10.1007/s10509-018-3358-2
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We study cosmological dynamics of a generalized Higgs inflation. By expanding
the action up to the second and third order in the small perturbations, we
study the primordial perturbation and its non-Gaussian distribution. We study
the non-Gaussian feature in both the equilateral and orthogonal configurations.
By adopting a quartic potential, we perform a numerical analysis on the model's
parameter space and compare the results with Planck2015 observational data. To
obtain some observational constraint, we focus on the self-coupling and the
non-minimal coupling parameters. We show that, in the presence of the
non-minimal coupling and the Galileon-like interaction, the self-coupling
parameter can be reduced to the order of $10^{-6}$ which is much larger than
the value that CMB normalization suggests for this self-coupling.
|
[
{
"created": "Sun, 24 Jun 2018 11:18:30 GMT",
"version": "v1"
}
] |
2018-06-26
|
[
[
"Nozari",
"Kourosh",
""
],
[
"Shafizadeh",
"S.",
""
],
[
"Rashidi",
"N.",
""
]
] |
We study cosmological dynamics of a generalized Higgs inflation. By expanding the action up to the second and third order in the small perturbations, we study the primordial perturbation and its non-Gaussian distribution. We study the non-Gaussian feature in both the equilateral and orthogonal configurations. By adopting a quartic potential, we perform a numerical analysis on the model's parameter space and compare the results with Planck2015 observational data. To obtain some observational constraint, we focus on the self-coupling and the non-minimal coupling parameters. We show that, in the presence of the non-minimal coupling and the Galileon-like interaction, the self-coupling parameter can be reduced to the order of $10^{-6}$ which is much larger than the value that CMB normalization suggests for this self-coupling.
|
1805.08764
|
Yakov Shlapentokh-Rothman
|
Mihalis Dafermos and Yakov Shlapentokh-Rothman
|
Rough initial data and the strength of the blue-shift instability on
cosmological black holes with $\Lambda > 0$
|
references added and minor revisions
| null |
10.1088/1361-6382/aadbcf
| null |
gr-qc math-ph math.AP math.DG math.MP
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We consider the wave equation on Reissner-Nordstr\"om-de Sitter and more
generally Kerr-Newman-de Sitter black hole spacetimes with $\Lambda>0$. The
strength of the blue-shift instability associated to the Cauchy horizon of
these spacetimes has been the subject of much discussion, since-in contrast to
the $\Lambda=0$ case-the competition with the decay associated to the region
between the event and cosmological horizons is delicate. Of particular interest
is the question as to whether generic, admissible initial data posed on a
Cauchy surface lead to solutions whose local energy blows up at the Cauchy
horizon, for this statement holds in the $\Lambda = 0$ case and would
correspond precisely to the blow up required by Christodoulou's formulation of
strong cosmic censorship. Some recent heuristic work suggests that the answer
is in general negative for solutions arising from sufficiently smooth data,
such that for all such data, the arising solutions have finite local energy at
the Cauchy horizon. In this short note, we shall show in contrast that, by
slightly relaxing the smoothness assumption on initial data, we are able to
prove the analogue of the Christodoulou statement in the affirmative, i.e. we
show that for generic data in our allowed class, the local energy blow-up
statement indeed holds at the Cauchy horizon, for all subextremal black hole
parameter ranges. We present two distinct proofs. Our slightly enlarged class
of initial data is still sufficiently regular to ensure both stability and
decay properties in the region between the event and cosmological horizons as
well as the boundedness and continuous extendibility beyond the Cauchy horizon.
This suggests thus that it is finally this class which may provide the correct
setting to formulate the genericity condition in strong cosmic censorship.
|
[
{
"created": "Tue, 22 May 2018 17:50:44 GMT",
"version": "v1"
},
{
"created": "Mon, 18 Jun 2018 00:08:55 GMT",
"version": "v2"
}
] |
2018-09-26
|
[
[
"Dafermos",
"Mihalis",
""
],
[
"Shlapentokh-Rothman",
"Yakov",
""
]
] |
We consider the wave equation on Reissner-Nordstr\"om-de Sitter and more generally Kerr-Newman-de Sitter black hole spacetimes with $\Lambda>0$. The strength of the blue-shift instability associated to the Cauchy horizon of these spacetimes has been the subject of much discussion, since-in contrast to the $\Lambda=0$ case-the competition with the decay associated to the region between the event and cosmological horizons is delicate. Of particular interest is the question as to whether generic, admissible initial data posed on a Cauchy surface lead to solutions whose local energy blows up at the Cauchy horizon, for this statement holds in the $\Lambda = 0$ case and would correspond precisely to the blow up required by Christodoulou's formulation of strong cosmic censorship. Some recent heuristic work suggests that the answer is in general negative for solutions arising from sufficiently smooth data, such that for all such data, the arising solutions have finite local energy at the Cauchy horizon. In this short note, we shall show in contrast that, by slightly relaxing the smoothness assumption on initial data, we are able to prove the analogue of the Christodoulou statement in the affirmative, i.e. we show that for generic data in our allowed class, the local energy blow-up statement indeed holds at the Cauchy horizon, for all subextremal black hole parameter ranges. We present two distinct proofs. Our slightly enlarged class of initial data is still sufficiently regular to ensure both stability and decay properties in the region between the event and cosmological horizons as well as the boundedness and continuous extendibility beyond the Cauchy horizon. This suggests thus that it is finally this class which may provide the correct setting to formulate the genericity condition in strong cosmic censorship.
|
gr-qc/0606116
|
Gustav Holzegel
|
G.W. Gibbons, G. Holzegel
|
The Positive Mass and Isoperimetric Inequalities for Axisymmetric Black
Holes in four and five dimensions
|
21 pages, 3 figures
|
Class.Quant.Grav.23:6459-6478,2006
|
10.1088/0264-9381/23/22/022
|
DAMTP-2006-53
|
gr-qc hep-th
| null |
In this paper we revisit Brill's proof of positive mass for
three-dimensional, time-symmetric, axisymmetric initial data and generalise his
argument in various directions. In 3+1 dimensions, we include an apparent
horizon in the initial data and prove the Riemannian Penrose inequality in a
wide number of cases by an elementary argument. In the case of 4+1 dimensions
we obtain the analogue of Brill's formula for initial data admitting a
generalised form of axisymmetry. Including an apparent horizon in the initial
data, the Riemannian Penrose inequality is again proved for a large class of
cases. The results may have applications in numerical relativity.
|
[
{
"created": "Tue, 27 Jun 2006 12:01:34 GMT",
"version": "v1"
}
] |
2009-10-07
|
[
[
"Gibbons",
"G. W.",
""
],
[
"Holzegel",
"G.",
""
]
] |
In this paper we revisit Brill's proof of positive mass for three-dimensional, time-symmetric, axisymmetric initial data and generalise his argument in various directions. In 3+1 dimensions, we include an apparent horizon in the initial data and prove the Riemannian Penrose inequality in a wide number of cases by an elementary argument. In the case of 4+1 dimensions we obtain the analogue of Brill's formula for initial data admitting a generalised form of axisymmetry. Including an apparent horizon in the initial data, the Riemannian Penrose inequality is again proved for a large class of cases. The results may have applications in numerical relativity.
|
1101.1927
|
Hwee Kuan Lee
|
Hwee Kuan Lee
|
A Finite State Model for Time Travel
|
6 pages, 1 figure
| null | null | null |
gr-qc cond-mat.stat-mech math-ph math.MP
|
http://creativecommons.org/licenses/by/3.0/
|
A time machine that sends information back to the past may, in principle, be
built using closed time-like curves. However, the realization of a time machine
must be congruent with apparent paradoxes that arise from traveling back in
time. Using a simple model to analyze the consequences of time travel, we show
that several paradoxes, including the grandfather paradox and Deutsch's
unproven theorem paradox, are precluded by basic axioms of probability.
However, our model does not prohibit traveling back in time to affect past
events in a self-consistent manner.
|
[
{
"created": "Mon, 10 Jan 2011 19:13:01 GMT",
"version": "v1"
}
] |
2011-01-11
|
[
[
"Lee",
"Hwee Kuan",
""
]
] |
A time machine that sends information back to the past may, in principle, be built using closed time-like curves. However, the realization of a time machine must be congruent with apparent paradoxes that arise from traveling back in time. Using a simple model to analyze the consequences of time travel, we show that several paradoxes, including the grandfather paradox and Deutsch's unproven theorem paradox, are precluded by basic axioms of probability. However, our model does not prohibit traveling back in time to affect past events in a self-consistent manner.
|
0912.2812
|
Vladimir Dzhunushaliev
|
V. Dzhunushaliev, V. Folomeev, B. Kleihaus and J. Kunz
|
Some thick brane solutions in $f(R)$-gravity
|
final version
|
JHEP 1004:130,2010
|
10.1007/JHEP04(2010)130
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The thick brane model is considered in $f(R)\sim R^n$ gravity. It is shown
that regular asymptotically anti-de Sitter solutions exist in some range of
values of the parameter $n$. A peculiar feature of this model is the existence
of a fixed point in the phase plane where all solutions start, and the brane
can be placed at this point. The presence of the fixed point allows to avoid
fine tuning of the model parameters to obtain thick brane solutions.
|
[
{
"created": "Tue, 15 Dec 2009 07:06:48 GMT",
"version": "v1"
},
{
"created": "Thu, 6 May 2010 12:22:56 GMT",
"version": "v2"
}
] |
2010-05-12
|
[
[
"Dzhunushaliev",
"V.",
""
],
[
"Folomeev",
"V.",
""
],
[
"Kleihaus",
"B.",
""
],
[
"Kunz",
"J.",
""
]
] |
The thick brane model is considered in $f(R)\sim R^n$ gravity. It is shown that regular asymptotically anti-de Sitter solutions exist in some range of values of the parameter $n$. A peculiar feature of this model is the existence of a fixed point in the phase plane where all solutions start, and the brane can be placed at this point. The presence of the fixed point allows to avoid fine tuning of the model parameters to obtain thick brane solutions.
|
gr-qc/0507133
|
Filimonova Irina V
|
V.A.Petrov
|
Plenary talk presented at Workshop on High Energy Physics&Field Theory
(Protvino, Russia, 2004)
|
Plenary talk presented at Workshop on High Energy Physics&Field
Theory (Protvino, Russia, 2004)
| null | null |
HEPFT/2004/14
|
gr-qc
| null |
The problems concerning a possible discovery of the mini block holes at
earthly accelerators are discussed.
|
[
{
"created": "Fri, 29 Jul 2005 08:39:40 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Petrov",
"V. A.",
""
]
] |
The problems concerning a possible discovery of the mini block holes at earthly accelerators are discussed.
|
gr-qc/9702036
|
P. S. Joshi
|
P. S. Joshi
|
Gravitational Collapse
|
40pages, latex, one eps figure included, appeared in `Singularities,
Black Holes and Cosmic Censorship' (On the fortieth anniversary of the
Raychaudhuri Equation), IUCAA publication, Pune, India
| null | null | null |
gr-qc hep-th
| null |
We review here some recent developments on the issue of final fate of
gravitational collapse within the framework of Einstein theory of gravity. The
structure of collapsed object is discussed in terms of either a black hole or a
singularity having causal connection with outside universe. Implications for
cosmic censorship are discussed.
|
[
{
"created": "Wed, 19 Feb 1997 08:18:02 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Joshi",
"P. S.",
""
]
] |
We review here some recent developments on the issue of final fate of gravitational collapse within the framework of Einstein theory of gravity. The structure of collapsed object is discussed in terms of either a black hole or a singularity having causal connection with outside universe. Implications for cosmic censorship are discussed.
|
gr-qc/0501047
|
Dan-Tao Peng
|
Dan-Tao Peng
|
The Cosmological Perturbation of Braneworld with An Anisotropic Bulk
|
no figures, revised version, some references added
| null | null |
USTC-ICTS-05-02
|
gr-qc
| null |
The braneworld cosmological model was constructed by embedding a 3-brane into
a higher dimensional bulk background geometry and the usual matter of our
universe was assumed to be confined in the brane while the gravity can
propagate in the bulk. By considering that the bulk geometry is anisotropic,
after reviewed the separable solution for the bulk metric and the result that
the anisotropic property of the bulk can support the perfect fluid kind of the
matter in the brane, we develop a formalism of the cosmological perturbation
for this kind of anisotropic braneworld model. As in isotropic case, we can
also decompose the perturbation into scalar, vector and tensor modes, we find
that the formalism for the anisotropic braneworld cosmological perturbation are
very different from the isotropic case. The anisotropic effect can be reflected
in the tensor modes which dominated the cosmological gravitation waves.
Finally, we also discussed the perturbed Einstein equations governed the
dynamics of the bulk geometry and the brane with the junction conditions.
|
[
{
"created": "Fri, 14 Jan 2005 08:40:35 GMT",
"version": "v1"
},
{
"created": "Tue, 18 Jan 2005 05:04:53 GMT",
"version": "v2"
}
] |
2007-05-23
|
[
[
"Peng",
"Dan-Tao",
""
]
] |
The braneworld cosmological model was constructed by embedding a 3-brane into a higher dimensional bulk background geometry and the usual matter of our universe was assumed to be confined in the brane while the gravity can propagate in the bulk. By considering that the bulk geometry is anisotropic, after reviewed the separable solution for the bulk metric and the result that the anisotropic property of the bulk can support the perfect fluid kind of the matter in the brane, we develop a formalism of the cosmological perturbation for this kind of anisotropic braneworld model. As in isotropic case, we can also decompose the perturbation into scalar, vector and tensor modes, we find that the formalism for the anisotropic braneworld cosmological perturbation are very different from the isotropic case. The anisotropic effect can be reflected in the tensor modes which dominated the cosmological gravitation waves. Finally, we also discussed the perturbed Einstein equations governed the dynamics of the bulk geometry and the brane with the junction conditions.
|
gr-qc/9710110
|
Dario Nunez
|
Dario Nunez
|
Oscillating shells: A model for a variable cosmic object
| null |
Astrophys.J. 482 (1997) 963-970
|
10.1086/304190
| null |
gr-qc
| null |
A model for a possible variable cosmic object is presented. The model
consists of a massive shell surrounding a compact object. The gravitational and
self-gravitational forces tend to collapse the shell, but the internal
tangential stresses oppose the collapse. The combined action of the two types
of forces is studied and several cases are presented. In particular, we
investigate the spherically symmetric case in which the shell oscillates
radially around a central compact object.
|
[
{
"created": "Thu, 23 Oct 1997 14:52:51 GMT",
"version": "v1"
}
] |
2009-10-30
|
[
[
"Nunez",
"Dario",
""
]
] |
A model for a possible variable cosmic object is presented. The model consists of a massive shell surrounding a compact object. The gravitational and self-gravitational forces tend to collapse the shell, but the internal tangential stresses oppose the collapse. The combined action of the two types of forces is studied and several cases are presented. In particular, we investigate the spherically symmetric case in which the shell oscillates radially around a central compact object.
|
2111.13270
|
Orfeu Bertolami
|
Riccardo March, Orfeu Bertolami, Marco Muccino, Claudio Gomes, Simone
Dell'Agnello
|
Cassini and extra force constraints to nonminimally coupled gravity with
screening mechanism
|
27 pages, 11 figuures
| null |
10.1103/PhysRevD.105.044048
| null |
gr-qc
|
http://creativecommons.org/licenses/by/4.0/
|
We consider a nonminimally coupled curvature-matter gravity theory at the
Solar System scale. Both a fifth force of Yukawa type and a further
non-Newtonian extra force that arises from the nonminimal coupling are present
in the solar interior and in the solar atmosphere up to interplanetary space.
The extra force depends on the spatial gradient of space-time curvature R. The
conditions under which the effects of such forces can be screened by the
chameleon mechanism and be made consistent with Cassini measurement of PPN
parameter $\gamma$ are examined. This consistency analysis requires a specific
study of Sun's dynamical contribution to the arising forces at all its layers.
|
[
{
"created": "Thu, 25 Nov 2021 23:11:05 GMT",
"version": "v1"
}
] |
2022-03-09
|
[
[
"March",
"Riccardo",
""
],
[
"Bertolami",
"Orfeu",
""
],
[
"Muccino",
"Marco",
""
],
[
"Gomes",
"Claudio",
""
],
[
"Dell'Agnello",
"Simone",
""
]
] |
We consider a nonminimally coupled curvature-matter gravity theory at the Solar System scale. Both a fifth force of Yukawa type and a further non-Newtonian extra force that arises from the nonminimal coupling are present in the solar interior and in the solar atmosphere up to interplanetary space. The extra force depends on the spatial gradient of space-time curvature R. The conditions under which the effects of such forces can be screened by the chameleon mechanism and be made consistent with Cassini measurement of PPN parameter $\gamma$ are examined. This consistency analysis requires a specific study of Sun's dynamical contribution to the arising forces at all its layers.
|
0902.3652
|
David Brown
|
J. David Brown
|
Covariant formulations of BSSN and the standard gauge
|
6 pages, no figures. Notation has been improved and typos have been
corrected
|
Phys.Rev.D79:104029,2009
|
10.1103/PhysRevD.79.104029
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The BSSN and standard gauge equations are written in covariant form with
respect to spatial coordinate transformations. The BSSN variables are defined
as tensors with no density weights. This allows us to evolve a given set of
initial data using two different coordinate systems and to relate the results
using the familiar tensor transformation rules. Two variants of the covariant
equations are considered. These differ from one another in the way that the
determinant of the conformal metric is evolved.
|
[
{
"created": "Fri, 20 Feb 2009 20:31:49 GMT",
"version": "v1"
},
{
"created": "Fri, 22 May 2009 13:20:16 GMT",
"version": "v2"
}
] |
2009-07-30
|
[
[
"Brown",
"J. David",
""
]
] |
The BSSN and standard gauge equations are written in covariant form with respect to spatial coordinate transformations. The BSSN variables are defined as tensors with no density weights. This allows us to evolve a given set of initial data using two different coordinate systems and to relate the results using the familiar tensor transformation rules. Two variants of the covariant equations are considered. These differ from one another in the way that the determinant of the conformal metric is evolved.
|
2405.06197
|
Yitian Chen
|
Yitian Chen, Michael Boyle, Nils Deppe, Lawrence E. Kidder, Keefe
Mitman, Jordan Moxon, Kyle C. Nelli, Harald P. Pfeiffer, Mark A. Scheel,
William Throwe, Nils L. Vu, Saul A. Teukolsky
|
Improved frequency spectra of gravitational waves with memory in a
binary-black-hole simulation
|
24 pages, 11 figures, 5 tables
| null | null | null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Numerical relativists can now produce gravitational waveforms with memory
effects routinely and accurately. The gravitational-wave memory effect contains
very low-frequency components, including a persistent offset. The presence of
these components violates basic assumptions about time-shift behavior
underpinning standard data-analysis techniques in gravitational-wave astronomy.
This poses a challenge to the analysis of waveform spectra: How to preserve the
low-frequency characteristics when transforming a time-domain waveform to the
frequency domain. To tackle this challenge, we revisit the preprocessing
procedures applied to the waveforms that contain memory effects. We find
inconsistency between the zero-frequency limit of displacement memory and the
low- frequency spectrum of the same memory preprocessed using the common scheme
in literature. To resolve the inconsistency, we propose a new robust
preprocessing scheme that produces the spectra of memory waveforms more
faithfully. Using this new scheme, we inspect several characteristics of the
spectrum of a memory waveform. In particular, we find a discernible beating
pattern formed by the dominant oscillatory mode and the displacement memory.
This pattern is absent in the spectrum of a waveform without memory. The
difference between the memory and no-memory waveforms is too small to be
observed by current-generation detectors in a single binary-black-hole event.
Detecting the memory in a single event is likely to occur in the era of
next-generation detectors.
|
[
{
"created": "Fri, 10 May 2024 02:24:01 GMT",
"version": "v1"
}
] |
2024-05-13
|
[
[
"Chen",
"Yitian",
""
],
[
"Boyle",
"Michael",
""
],
[
"Deppe",
"Nils",
""
],
[
"Kidder",
"Lawrence E.",
""
],
[
"Mitman",
"Keefe",
""
],
[
"Moxon",
"Jordan",
""
],
[
"Nelli",
"Kyle C.",
""
],
[
"Pfeiffer",
"Harald P.",
""
],
[
"Scheel",
"Mark A.",
""
],
[
"Throwe",
"William",
""
],
[
"Vu",
"Nils L.",
""
],
[
"Teukolsky",
"Saul A.",
""
]
] |
Numerical relativists can now produce gravitational waveforms with memory effects routinely and accurately. The gravitational-wave memory effect contains very low-frequency components, including a persistent offset. The presence of these components violates basic assumptions about time-shift behavior underpinning standard data-analysis techniques in gravitational-wave astronomy. This poses a challenge to the analysis of waveform spectra: How to preserve the low-frequency characteristics when transforming a time-domain waveform to the frequency domain. To tackle this challenge, we revisit the preprocessing procedures applied to the waveforms that contain memory effects. We find inconsistency between the zero-frequency limit of displacement memory and the low- frequency spectrum of the same memory preprocessed using the common scheme in literature. To resolve the inconsistency, we propose a new robust preprocessing scheme that produces the spectra of memory waveforms more faithfully. Using this new scheme, we inspect several characteristics of the spectrum of a memory waveform. In particular, we find a discernible beating pattern formed by the dominant oscillatory mode and the displacement memory. This pattern is absent in the spectrum of a waveform without memory. The difference between the memory and no-memory waveforms is too small to be observed by current-generation detectors in a single binary-black-hole event. Detecting the memory in a single event is likely to occur in the era of next-generation detectors.
|
gr-qc/0408017
|
Schmidt H.-J.
|
H.-J. Schmidt
|
Schwarzschild and Synge once again
|
2 pages, LaTeX, submitted for publication; 2 references, one Note,
and an Acknowledgement are added
|
Gen.Rel.Grav. 37 (2005) 1157-1158
|
10.1007/s10714-005-0100-5
| null |
gr-qc
| null |
We complete the historical overview about the geometry of a Schwarzschild
black hole at its horizon by emphasizing the contribution made by J. L. Synge
in 1950 to its clarification.
|
[
{
"created": "Fri, 6 Aug 2004 06:54:15 GMT",
"version": "v1"
},
{
"created": "Tue, 24 Aug 2004 14:29:12 GMT",
"version": "v2"
}
] |
2009-11-10
|
[
[
"Schmidt",
"H. -J.",
""
]
] |
We complete the historical overview about the geometry of a Schwarzschild black hole at its horizon by emphasizing the contribution made by J. L. Synge in 1950 to its clarification.
|
gr-qc/0507068
|
Andrea Nerozzi Mr
|
Andrea Nerozzi, Marco Bruni, Virginia Re, Lior M. Burko
|
Towards a wave-extraction method for numerical relativity: IV. Testing
the quasi-Kinnersley method in the Bondi-Sachs framework
|
12 pages, 11 figures
|
Phys.Rev. D73 (2006) 044020
|
10.1103/PhysRevD.73.044020
| null |
gr-qc
| null |
We present a numerical study of the evolution of a non-linearly disturbed
black hole described by the Bondi--Sachs metric, for which the outgoing
gravitational waves can readily be found using the news function. We compare
the gravitational wave output obtained with the use of the news function in the
Bondi--Sachs framework, with that obtained from the Weyl scalars, where the
latter are evaluated in a quasi-Kinnersley tetrad. The latter method has the
advantage of being applicable to any formulation of Einstein's
equations---including the ADM formulation and its various descendants---in
addition to being robust. Using the non-linearly disturbed Bondi--Sachs black
hole as a test-bed, we show that the two approaches give wave-extraction
results which are in very good agreement. When wave extraction through the Weyl
scalars is done in a non quasi-Kinnersley tetrad, the results are markedly
different from those obtained using the news function.
|
[
{
"created": "Fri, 15 Jul 2005 20:46:27 GMT",
"version": "v1"
},
{
"created": "Wed, 15 Feb 2006 18:23:22 GMT",
"version": "v2"
}
] |
2009-11-11
|
[
[
"Nerozzi",
"Andrea",
""
],
[
"Bruni",
"Marco",
""
],
[
"Re",
"Virginia",
""
],
[
"Burko",
"Lior M.",
""
]
] |
We present a numerical study of the evolution of a non-linearly disturbed black hole described by the Bondi--Sachs metric, for which the outgoing gravitational waves can readily be found using the news function. We compare the gravitational wave output obtained with the use of the news function in the Bondi--Sachs framework, with that obtained from the Weyl scalars, where the latter are evaluated in a quasi-Kinnersley tetrad. The latter method has the advantage of being applicable to any formulation of Einstein's equations---including the ADM formulation and its various descendants---in addition to being robust. Using the non-linearly disturbed Bondi--Sachs black hole as a test-bed, we show that the two approaches give wave-extraction results which are in very good agreement. When wave extraction through the Weyl scalars is done in a non quasi-Kinnersley tetrad, the results are markedly different from those obtained using the news function.
|
1401.0327
|
Seth A. Major
|
Jeremy Adelman, Franz Hinterleitner, Seth Major
|
Quantum volume and length fluctuations in a midi-superspace model of
Minkowski space
|
43 pages
|
Class. Quantum Grav. 32 (2015) 055009
|
10.1088/0264-9381/32/5/055009
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
In a (1+1)-dimensional midi-superspace model for gravitational plane waves, a
flat space-time condition is imposed with constraints derived from null Killing
vectors. Solutions to a straightforward regularization of these constraints
have diverging length and volume expectation values. Physically acceptable
solutions in the kinematic Hilbert space are obtained from the original
constraint by multiplying with a power of the volume operator and by a similar
modification of the Hamiltonian constraint, which is used in a regularization
of the constraints. The solutions of the modified Killing constraint have
finite expectation values of geometric quantities. Further, the expectation
value of the original Killing constraint vanishes, but its moment is
non-vanishing. As the power of the volume grows the moment of the original
constraint grows, while the moments of volume and length both decrease. Thus,
these states provide possible kinematic states for flat space, with
fluctuations. As a consequence of the regularization of operators the quantum
uncertainty relations between geometric quantities such as length and its
conjugate momentum do not reflect naive expectations from the classical Poisson
bracket relations.
|
[
{
"created": "Wed, 1 Jan 2014 20:46:24 GMT",
"version": "v1"
},
{
"created": "Thu, 27 Feb 2014 20:24:08 GMT",
"version": "v2"
},
{
"created": "Thu, 25 Sep 2014 21:09:44 GMT",
"version": "v3"
},
{
"created": "Thu, 28 Apr 2016 09:38:30 GMT",
"version": "v4"
}
] |
2016-04-29
|
[
[
"Adelman",
"Jeremy",
""
],
[
"Hinterleitner",
"Franz",
""
],
[
"Major",
"Seth",
""
]
] |
In a (1+1)-dimensional midi-superspace model for gravitational plane waves, a flat space-time condition is imposed with constraints derived from null Killing vectors. Solutions to a straightforward regularization of these constraints have diverging length and volume expectation values. Physically acceptable solutions in the kinematic Hilbert space are obtained from the original constraint by multiplying with a power of the volume operator and by a similar modification of the Hamiltonian constraint, which is used in a regularization of the constraints. The solutions of the modified Killing constraint have finite expectation values of geometric quantities. Further, the expectation value of the original Killing constraint vanishes, but its moment is non-vanishing. As the power of the volume grows the moment of the original constraint grows, while the moments of volume and length both decrease. Thus, these states provide possible kinematic states for flat space, with fluctuations. As a consequence of the regularization of operators the quantum uncertainty relations between geometric quantities such as length and its conjugate momentum do not reflect naive expectations from the classical Poisson bracket relations.
|
gr-qc/0106096
|
Charles Hellaby
|
Andrzej Krasinski and Charles Hellaby
|
Structure formation in the Lemaitre-Tolman model
|
LaTeX 2e plus 14 .eps & .ps figure files. 33 pages including figures.
Minor revisions of text and data make it more precise and consistent.
Currently scheduled for Phys Rev D vol 64, December 15 issue
|
Phys.Rev.D65:023501,2002
|
10.1103/PhysRevD.65.023501
|
uct-cosmology-01/06
|
gr-qc astro-ph
| null |
Structure formation within the Lemaitre-Tolman model is investigated in a
general manner. We seek models such that the initial density perturbation
within a homogeneous background has a smaller mass than the structure into
which it will develop, and the perturbation then accretes more mass during
evolution. This is a generalisation of the approach taken by Bonnor in 1956. It
is proved that any two spherically symmetric density profiles specified on any
two constant time slices can be joined by a Lemaitre-Tolman evolution, and
exact implicit formulae for the arbitrary functions that determine the
resulting L-T model are obtained. Examples of the process are investigated
numerically.
|
[
{
"created": "Fri, 29 Jun 2001 17:05:28 GMT",
"version": "v1"
},
{
"created": "Wed, 31 Oct 2001 12:06:00 GMT",
"version": "v2"
}
] |
2008-11-26
|
[
[
"Krasinski",
"Andrzej",
""
],
[
"Hellaby",
"Charles",
""
]
] |
Structure formation within the Lemaitre-Tolman model is investigated in a general manner. We seek models such that the initial density perturbation within a homogeneous background has a smaller mass than the structure into which it will develop, and the perturbation then accretes more mass during evolution. This is a generalisation of the approach taken by Bonnor in 1956. It is proved that any two spherically symmetric density profiles specified on any two constant time slices can be joined by a Lemaitre-Tolman evolution, and exact implicit formulae for the arbitrary functions that determine the resulting L-T model are obtained. Examples of the process are investigated numerically.
|
0811.1799
|
Thomas Sotiriou
|
Thomas P. Sotiriou
|
Covariant Effective Action for Loop Quantum Cosmology from Order
Reduction
|
minor changes to match published version
|
Phys.Rev.D79:044035,2009
|
10.1103/PhysRevD.79.044035
| null |
gr-qc astro-ph hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Loop quantum cosmology (LQC) seems to be predicting modified effective
Friedmann equations without extra degrees of freedom. A puzzle arises if one
decides to seek for a covariant effective action which would lead to the given
Friedmann equation: The Einstein--Hilbert action is the only action that leads
to second order field equations and, hence, there exists no covariant action
which, under metric variation, leads to modified Friedmann equation without
extra degrees of freedom. It is shown that, at least for isotropic models in
LQC, this issue is naturally resolved and a covariant effective action can be
found if one considers higher order theories of gravity but faithfully follows
effective field theory techniques. However, our analysis also raises doubts on
whether a covariant description without background structures can be found for
anisotropic models.
|
[
{
"created": "Tue, 11 Nov 2008 23:45:10 GMT",
"version": "v1"
},
{
"created": "Thu, 26 Feb 2009 21:33:36 GMT",
"version": "v2"
}
] |
2009-02-26
|
[
[
"Sotiriou",
"Thomas P.",
""
]
] |
Loop quantum cosmology (LQC) seems to be predicting modified effective Friedmann equations without extra degrees of freedom. A puzzle arises if one decides to seek for a covariant effective action which would lead to the given Friedmann equation: The Einstein--Hilbert action is the only action that leads to second order field equations and, hence, there exists no covariant action which, under metric variation, leads to modified Friedmann equation without extra degrees of freedom. It is shown that, at least for isotropic models in LQC, this issue is naturally resolved and a covariant effective action can be found if one considers higher order theories of gravity but faithfully follows effective field theory techniques. However, our analysis also raises doubts on whether a covariant description without background structures can be found for anisotropic models.
|
2203.00619
|
Manuel Hohmann
|
Sebastian Bahamonde, Konstantinos F. Dialektopoulos, Manuel Hohmann,
Jackson Levi Said, Christian Pfeifer, Emmanuel N. Saridakis
|
Perturbations in Non-Flat Cosmology for $f(T)$ gravity
|
21 pagers, no figures
| null |
10.1140/epjc/s10052-023-11322-3
| null |
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The study of cosmological perturbation theory in $f(T)$ gravity is a topic of
great interest in teleparallel gravity since this is one of the simplest
generalizations of the theory that modifies the teleparallel equivalent of
general relativity. In this work, we explore the possibility of a non-flat FLRW
background solution and perform perturbations for positively as well as
negatively curved spatial geometries, together with a comparison to the flat
case. We determine the generalized behaviour of the perturbative modes for this
non-flat FLRW setting for arbitrary $f(T)$ models, when the most general
homogeneous and isotropic background tetrads are used. We also identify
propagating modes in this setup, and relate this with the case of a flat
cosmology.
|
[
{
"created": "Tue, 1 Mar 2022 17:00:58 GMT",
"version": "v1"
},
{
"created": "Tue, 29 Mar 2022 17:40:00 GMT",
"version": "v2"
}
] |
2023-03-22
|
[
[
"Bahamonde",
"Sebastian",
""
],
[
"Dialektopoulos",
"Konstantinos F.",
""
],
[
"Hohmann",
"Manuel",
""
],
[
"Said",
"Jackson Levi",
""
],
[
"Pfeifer",
"Christian",
""
],
[
"Saridakis",
"Emmanuel N.",
""
]
] |
The study of cosmological perturbation theory in $f(T)$ gravity is a topic of great interest in teleparallel gravity since this is one of the simplest generalizations of the theory that modifies the teleparallel equivalent of general relativity. In this work, we explore the possibility of a non-flat FLRW background solution and perform perturbations for positively as well as negatively curved spatial geometries, together with a comparison to the flat case. We determine the generalized behaviour of the perturbative modes for this non-flat FLRW setting for arbitrary $f(T)$ models, when the most general homogeneous and isotropic background tetrads are used. We also identify propagating modes in this setup, and relate this with the case of a flat cosmology.
|
1807.11807
|
Matteo Luca Ruggiero
|
Lorenzo Iorio, Matteo Luca Ruggiero
|
Constraining some $r^{-n}$ extra-potentials in modified gravity models
with LAGEOS-type laser-ranged geodetic satellites
|
20 pages, 4 figures; revised to match the version accepted for
publication in JCAP
|
JCAP10(2018)021
|
10.1088/1475-7516/2018/10/021
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We focus on several models of modified gravity which share the characteristic
of leading to perturbations of the Newtonian potential $\propto K_2~r^{-2}$ and
$\propto K_3~r^{-3}$. In particular, by using existing long data records of the
LAGEOS satellites, tracked on an almost continuous basis with the Satellite
Laser Ranging (SLR) technique, we set preliminary constraints on the free
parameters $K_2,~K_3$ in a model-independent, phenomenological way. We obtain
$\left|K_2\right|\lesssim 2.1\times 10^6~\textrm{m}^4~\textrm{s}^{-2},~
-2.5\times 10^{12}~\textrm{m}^5~\textrm{s}^{-2}\lesssim K_3 \lesssim 4.1\times
10^{12}~\textrm{m}^5~\textrm{s}^{-2}.$ They are several orders of magnitude
tighter than corresponding bounds existing in the literature inferred with
different techniques and in other astronomical and astrophysical scenarios.
Then, we specialize them to the different parameters characterizing the various
models considered. The availability of SLR data records of increasing length
and accuracy will allow to further refine and strengthen the present results.
|
[
{
"created": "Tue, 31 Jul 2018 13:25:47 GMT",
"version": "v1"
},
{
"created": "Thu, 4 Oct 2018 15:14:50 GMT",
"version": "v2"
}
] |
2018-10-17
|
[
[
"Iorio",
"Lorenzo",
""
],
[
"Ruggiero",
"Matteo Luca",
""
]
] |
We focus on several models of modified gravity which share the characteristic of leading to perturbations of the Newtonian potential $\propto K_2~r^{-2}$ and $\propto K_3~r^{-3}$. In particular, by using existing long data records of the LAGEOS satellites, tracked on an almost continuous basis with the Satellite Laser Ranging (SLR) technique, we set preliminary constraints on the free parameters $K_2,~K_3$ in a model-independent, phenomenological way. We obtain $\left|K_2\right|\lesssim 2.1\times 10^6~\textrm{m}^4~\textrm{s}^{-2},~ -2.5\times 10^{12}~\textrm{m}^5~\textrm{s}^{-2}\lesssim K_3 \lesssim 4.1\times 10^{12}~\textrm{m}^5~\textrm{s}^{-2}.$ They are several orders of magnitude tighter than corresponding bounds existing in the literature inferred with different techniques and in other astronomical and astrophysical scenarios. Then, we specialize them to the different parameters characterizing the various models considered. The availability of SLR data records of increasing length and accuracy will allow to further refine and strengthen the present results.
|
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