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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1504.07983
|
John Bayron Orjuela Quintana
|
Juan C. Bueno-S\'anchez, J. Bayron Orjuela-Quintana and C\'esar A.
Valenzuela-Toledo
|
On the coupling of vector fields to the Gauss-Bonnet invariant
|
Typos corrected, some clarifying comments added. Matches the
published version
|
Rev. Acad. Colomb. Cienc. Ex. Fis. Nat., 45(174), 67-82 (2021)
|
10.18257/raccefyn.1146
| null |
gr-qc astro-ph.CO hep-ph hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Inflationary models including vector fields have attracted a great deal of
attention over the past decade. Such an interest owes to the fact that they
might contribute to, or even be fully responsible for, the curvature
perturbation imprinted in the cosmic microwave background. However, the
necessary breaking of the vector field's conformal invariance during inflation
is not without problems. In recent years, it has been realized that a number of
instabilities endangering the consistency of the theory arise when the
conformal invariance is broken by means of a non-minimal coupling to gravity.
In this paper, we consider a massive vector field non-minimally coupled to
gravity through the Gauss-Bonnet invariant, and investigate whether the vector
can play the role of a curvaton while evading the emergence of instabilities
and preserves the large-scale isotropy.
|
[
{
"created": "Wed, 29 Apr 2015 04:11:18 GMT",
"version": "v1"
},
{
"created": "Mon, 7 Dec 2020 08:09:31 GMT",
"version": "v2"
},
{
"created": "Wed, 9 Dec 2020 16:28:28 GMT",
"version": "v3"
},
{
"created": "Wed, 21 Apr 2021 14:36:31 GMT",
"version": "v4"
}
] |
2023-04-17
|
[
[
"Bueno-Sánchez",
"Juan C.",
""
],
[
"Orjuela-Quintana",
"J. Bayron",
""
],
[
"Valenzuela-Toledo",
"César A.",
""
]
] |
Inflationary models including vector fields have attracted a great deal of attention over the past decade. Such an interest owes to the fact that they might contribute to, or even be fully responsible for, the curvature perturbation imprinted in the cosmic microwave background. However, the necessary breaking of the vector field's conformal invariance during inflation is not without problems. In recent years, it has been realized that a number of instabilities endangering the consistency of the theory arise when the conformal invariance is broken by means of a non-minimal coupling to gravity. In this paper, we consider a massive vector field non-minimally coupled to gravity through the Gauss-Bonnet invariant, and investigate whether the vector can play the role of a curvaton while evading the emergence of instabilities and preserves the large-scale isotropy.
|
1111.5785
|
Bogus{\l}aw Broda
|
Bogus{\l}aw Broda
|
"Microscopic" approach to the Ricci dark energy
|
7 pages
|
International Journal of Modern Physics D 21 No. 6 (2012) 1250053
|
10.1142/S0218271812500538
| null |
gr-qc astro-ph.CO hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
A derivation of the Ricci dark energy from quantum field theory of
fluctuating "matter" fields in a classical gravitational background is
presented. The coupling to the dark energy, the parameter 'a', is estimated in
the framework of our formalism, and qualitatively it appears to be within
observational expectations.
|
[
{
"created": "Thu, 24 Nov 2011 14:52:34 GMT",
"version": "v1"
},
{
"created": "Fri, 2 Dec 2011 15:05:38 GMT",
"version": "v2"
},
{
"created": "Tue, 5 Jun 2012 14:15:03 GMT",
"version": "v3"
}
] |
2012-06-06
|
[
[
"Broda",
"Bogusław",
""
]
] |
A derivation of the Ricci dark energy from quantum field theory of fluctuating "matter" fields in a classical gravitational background is presented. The coupling to the dark energy, the parameter 'a', is estimated in the framework of our formalism, and qualitatively it appears to be within observational expectations.
|
gr-qc/0003037
|
Laszlo A. Gergely
|
L\'aszl\'o \'A. Gergely
|
Second post-Newtonian radiative evolution of the relative orientations
of angular momenta in spinning compact binaries
|
8 pages, to appear in Phys. Rev. D
|
Phys.Rev. D62 (2000) 024007
|
10.1103/PhysRevD.62.024007
| null |
gr-qc
| null |
The radiative evolution of the relative orientations of the spin and orbital
angular momentum vectors ${\bf S}_{{\bf 1}}, {\bf S}_{{\bf 2}}$ and ${\bf L}$,
characterizing a binary system on eccentric orbit is studied up to the second
post-Newtonian order. As an intermediate result, all Burke-Thorne type
instantaneous radiative changes in the spins are shown to average out over a
radial period. It is proved that spin-orbit and spin-spin terms contribute to
the radiative angular evolution equations, while Newtonian, first and second
post-Newtonian terms together with the leading order tail terms do not. In
complement to the spin-orbit contribution, given earlier, the spin-spin
contribution is computed and split into two-body and self-interaction parts.
The latter provide the second post-Newtonian order corrections to the 3/2 order
Lense-Thirring description.
|
[
{
"created": "Thu, 9 Mar 2000 14:31:41 GMT",
"version": "v1"
}
] |
2009-10-31
|
[
[
"Gergely",
"László Á.",
""
]
] |
The radiative evolution of the relative orientations of the spin and orbital angular momentum vectors ${\bf S}_{{\bf 1}}, {\bf S}_{{\bf 2}}$ and ${\bf L}$, characterizing a binary system on eccentric orbit is studied up to the second post-Newtonian order. As an intermediate result, all Burke-Thorne type instantaneous radiative changes in the spins are shown to average out over a radial period. It is proved that spin-orbit and spin-spin terms contribute to the radiative angular evolution equations, while Newtonian, first and second post-Newtonian terms together with the leading order tail terms do not. In complement to the spin-orbit contribution, given earlier, the spin-spin contribution is computed and split into two-body and self-interaction parts. The latter provide the second post-Newtonian order corrections to the 3/2 order Lense-Thirring description.
|
1111.2631
|
Mario Novello
|
M. Novello, F. T. Falciano, E. Goulart
|
Electromagnetic Geometry
| null | null | null | null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We show that Maxwell's electromagnetism can be mapped into the Born-Infeld
theory in a curved space-time, which depends only on the electromagnetic field
in a specific way. This map is valid for any value of the two lorentz
invariants $F$ and $G$ confirming that we have included all possible solutions
of Maxwell's equations. Our result seems to show that specifying the dynamics
and the space-time structure of a given theory can be viewed merely as a choice
of representation to describe the physical system.
|
[
{
"created": "Tue, 8 Nov 2011 17:08:51 GMT",
"version": "v1"
}
] |
2011-11-14
|
[
[
"Novello",
"M.",
""
],
[
"Falciano",
"F. T.",
""
],
[
"Goulart",
"E.",
""
]
] |
We show that Maxwell's electromagnetism can be mapped into the Born-Infeld theory in a curved space-time, which depends only on the electromagnetic field in a specific way. This map is valid for any value of the two lorentz invariants $F$ and $G$ confirming that we have included all possible solutions of Maxwell's equations. Our result seems to show that specifying the dynamics and the space-time structure of a given theory can be viewed merely as a choice of representation to describe the physical system.
|
1909.10328
|
Jackson Levi Said
|
Celia Escamilla-Rivera and Jackson Levi Said
|
Cosmological viable models in $f(T,B)$ gravity as solutions to the $H_0$
tension
|
21 pages, 8 figures
|
Class. Quantum Grav. 37 165002 (2020)
|
10.1088/1361-6382/ab939c
| null |
gr-qc astro-ph.CO hep-th physics.data-an
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
In this work we present a further investigation about Teleparallel Gravity
Cosmology. We demonstrate that according the current astrophysical data
(CC+Pantheon+BAO samplers with late universe measurements SH0ES+H0LiCOW), an
$f(T,B)$ theory can provide another interpretation to the oscillatory behaviour
of the dark energy equation of state when applied to late times. The four
$f(T,B)$ cosmological viable models proposed here can undergo an epoch of
late-time acceleration and reproduce quintessence and phantom regimes with a
transition along the phantom-divided line, making this theory a good approach
to modify the standard $\Lambda$CDM model.
|
[
{
"created": "Fri, 20 Sep 2019 13:50:46 GMT",
"version": "v1"
},
{
"created": "Tue, 2 Jun 2020 09:26:16 GMT",
"version": "v2"
}
] |
2021-05-07
|
[
[
"Escamilla-Rivera",
"Celia",
""
],
[
"Said",
"Jackson Levi",
""
]
] |
In this work we present a further investigation about Teleparallel Gravity Cosmology. We demonstrate that according the current astrophysical data (CC+Pantheon+BAO samplers with late universe measurements SH0ES+H0LiCOW), an $f(T,B)$ theory can provide another interpretation to the oscillatory behaviour of the dark energy equation of state when applied to late times. The four $f(T,B)$ cosmological viable models proposed here can undergo an epoch of late-time acceleration and reproduce quintessence and phantom regimes with a transition along the phantom-divided line, making this theory a good approach to modify the standard $\Lambda$CDM model.
|
2105.01906
|
Chris Stevens
|
J\"org Frauendiener, Jonathan Hakata, Chris Stevens
|
Can gravitational waves halt the expansion of the universe?
|
25 pages, 19 figures
| null | null | null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We numerically investigate the propagation of plane gravitational waves in
the form of an initial boundary value problem with de Sitter initial data. The
full non-linear Einstein equations with positive cosmological constant
$\lambda$ are written in the Friedrich-Nagy gauge which yields a wellposed
system. The propagation of a single wave and the collision of two with colinear
polarization are studied and contrasted with their Minkowskian analogues.
Unlike with $\lambda=0$, critical behaviours are found with $\lambda>0$ and are
based on the relationship between the wave profile and $\lambda$. We find that
choosing boundary data close to one of these bifurcations results in a "false"
steady state which violates the constraints. Simulations containing
(approximate) impulsive wave profiles are run and general features are
discussed. Analytic results of Woodard and Tsamis, which describe how
gravitational waves could affect an expansion rate at an initial instance of
time, are explored and generalized to the entire space-time. Finally we put
forward boundary conditions that, at least locally, slow down the expansion
considerably for a time.
|
[
{
"created": "Wed, 5 May 2021 07:41:11 GMT",
"version": "v1"
}
] |
2021-05-06
|
[
[
"Frauendiener",
"Jörg",
""
],
[
"Hakata",
"Jonathan",
""
],
[
"Stevens",
"Chris",
""
]
] |
We numerically investigate the propagation of plane gravitational waves in the form of an initial boundary value problem with de Sitter initial data. The full non-linear Einstein equations with positive cosmological constant $\lambda$ are written in the Friedrich-Nagy gauge which yields a wellposed system. The propagation of a single wave and the collision of two with colinear polarization are studied and contrasted with their Minkowskian analogues. Unlike with $\lambda=0$, critical behaviours are found with $\lambda>0$ and are based on the relationship between the wave profile and $\lambda$. We find that choosing boundary data close to one of these bifurcations results in a "false" steady state which violates the constraints. Simulations containing (approximate) impulsive wave profiles are run and general features are discussed. Analytic results of Woodard and Tsamis, which describe how gravitational waves could affect an expansion rate at an initial instance of time, are explored and generalized to the entire space-time. Finally we put forward boundary conditions that, at least locally, slow down the expansion considerably for a time.
|
1806.02141
|
Cosimo Bambi
|
Cosimo Bambi, Askar B. Abdikamalov, Dimitry Ayzenberg, Zheng Cao,
Honghui Liu, Sourabh Nampalliwar, Ashutosh Tripathi, Jingyi Wang-Ji, Yerong
Xu
|
RELXILL_NK: a relativistic reflection model for testing Einstein's
gravity
|
8 pages, 6 figures. Talk given at the "International Conference on
Quantum Gravity" (26-28 March 2018, Shenzhen, China). To appear in the
conference proceedings
|
Universe (2018) 4:79
|
10.3390/universe4070079
| null |
gr-qc astro-ph.HE
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Einstein's theory of general relativity was proposed over 100 years ago and
has successfully passed a large number of observational tests in the weak field
regime. However, the strong field regime is largely unexplored, and there are
many modified and alternative theories that have the same predictions as
Einstein's gravity for weak fields and present deviations when gravity becomes
strong. RELXILL_NK is the first relativistic reflection model for probing the
spacetime metric in the vicinity of astrophysical black holes and testing
Einstein's gravity in the strong field regime. Here we present our current
constraints on possible deviations from Einstein's gravity obtained from the
black holes in 1H0707-495, Ark 564, GX 339-4, and GS 1354-645.
|
[
{
"created": "Wed, 6 Jun 2018 12:14:50 GMT",
"version": "v1"
}
] |
2018-07-12
|
[
[
"Bambi",
"Cosimo",
""
],
[
"Abdikamalov",
"Askar B.",
""
],
[
"Ayzenberg",
"Dimitry",
""
],
[
"Cao",
"Zheng",
""
],
[
"Liu",
"Honghui",
""
],
[
"Nampalliwar",
"Sourabh",
""
],
[
"Tripathi",
"Ashutosh",
""
],
[
"Wang-Ji",
"Jingyi",
""
],
[
"Xu",
"Yerong",
""
]
] |
Einstein's theory of general relativity was proposed over 100 years ago and has successfully passed a large number of observational tests in the weak field regime. However, the strong field regime is largely unexplored, and there are many modified and alternative theories that have the same predictions as Einstein's gravity for weak fields and present deviations when gravity becomes strong. RELXILL_NK is the first relativistic reflection model for probing the spacetime metric in the vicinity of astrophysical black holes and testing Einstein's gravity in the strong field regime. Here we present our current constraints on possible deviations from Einstein's gravity obtained from the black holes in 1H0707-495, Ark 564, GX 339-4, and GS 1354-645.
|
1605.08440
|
Shahar Hod
|
Shahar Hod
|
The Hawking cascades of gravitons from higher-dimensional Schwarzschild
black holes
|
6 pages in Physics Letters B 756, 133 (2016)
|
Physics Letters B 756, 133 (2016)
|
10.1016/j.physletb.2016.03.002
| null |
gr-qc astro-ph.HE hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
It has recently been shown that the Hawking evaporation process of
$(3+1)$-dimensional Schwarzschild black holes is characterized by the
dimensionless ratio $\eta\equiv\tau_{\text{gap}}/\tau_{\text{emission}}\gg1$,
where $\tau_{\text{gap}}$ is the characteristic time gap between the emissions
of successive Hawking quanta and $\tau_{\text{emission}}$ is the characteristic
timescale required for an individual Hawking quantum to be emitted from the
Schwarzschild black hole. This strong inequality implies that the Hawking
cascade of gravitons from a $(3+1)$-dimensional Schwarzschild black hole is
extremely {\it sparse}. In the present paper we explore the semi-classical
Hawking evaporation rates of {\it higher}-dimensional Schwarzschild black
holes. We find that the dimensionless ratio
$\eta(D)\equiv{{\tau_{\text{gap}}}/{\tau_{\text{emission}}}}$, which
characterizes the Hawking emission of gravitons from the $(D+1)$-dimensional
Schwarzschild black holes, is a {\it decreasing} function of the spacetime
dimension. In particular, we show that higher-dimensional Schwarzschild black
holes with $D\gtrsim 10$ are characterized by the relation $\eta(D)<1$. Our
results thus imply that, contrary to the $(3+1)$-dimensional case, the
characteristic Hawking cascades of gravitons from these higher-dimensional
black holes have a {\it continuous} character.
|
[
{
"created": "Thu, 26 May 2016 20:00:07 GMT",
"version": "v1"
}
] |
2016-06-06
|
[
[
"Hod",
"Shahar",
""
]
] |
It has recently been shown that the Hawking evaporation process of $(3+1)$-dimensional Schwarzschild black holes is characterized by the dimensionless ratio $\eta\equiv\tau_{\text{gap}}/\tau_{\text{emission}}\gg1$, where $\tau_{\text{gap}}$ is the characteristic time gap between the emissions of successive Hawking quanta and $\tau_{\text{emission}}$ is the characteristic timescale required for an individual Hawking quantum to be emitted from the Schwarzschild black hole. This strong inequality implies that the Hawking cascade of gravitons from a $(3+1)$-dimensional Schwarzschild black hole is extremely {\it sparse}. In the present paper we explore the semi-classical Hawking evaporation rates of {\it higher}-dimensional Schwarzschild black holes. We find that the dimensionless ratio $\eta(D)\equiv{{\tau_{\text{gap}}}/{\tau_{\text{emission}}}}$, which characterizes the Hawking emission of gravitons from the $(D+1)$-dimensional Schwarzschild black holes, is a {\it decreasing} function of the spacetime dimension. In particular, we show that higher-dimensional Schwarzschild black holes with $D\gtrsim 10$ are characterized by the relation $\eta(D)<1$. Our results thus imply that, contrary to the $(3+1)$-dimensional case, the characteristic Hawking cascades of gravitons from these higher-dimensional black holes have a {\it continuous} character.
|
2007.12086
|
Dipanjan Dey
|
Parth Bambhaniya, Divyesh N. Solanki, Dipanjan Dey, Ashok B. Joshi,
Pankaj S. Joshi, Vishwa Patel
|
Precession of timelike bound orbits in Kerr spacetime
|
12 pages, 18 figures
| null |
10.1140/epjc/s10052-021-08997-x
| null |
gr-qc
|
http://creativecommons.org/licenses/by/4.0/
|
Astrometric observations of S-stars provide a unique opportunity to probe the
nature of Sagittarius-A* (Sgr-A*). In view of this, it has become important to
understand the nature and behavior of timelike bound trajectories of particles
around a massive central object. It is known now that whereas the Schwarzschild
black hole does not allow the negative precession for the S-stars, the naked
singularity spacetimes can admit the positive as well as negative precession
for the bound timelike orbits. In this context, we study the perihelion
precession of a test particle in the Kerr spacetime geometry. Considering some
approximations, we investigate whether the timelike bound orbits of a test
particle in Kerr spacetime can have negative precession. In this paper, we only
consider low eccentric timelike equatorial orbits. With these considerations,
we find that in Kerr spacetimes, negative precession of timelike bound orbits
is not allowed.
|
[
{
"created": "Thu, 23 Jul 2020 15:50:40 GMT",
"version": "v1"
}
] |
2021-03-17
|
[
[
"Bambhaniya",
"Parth",
""
],
[
"Solanki",
"Divyesh N.",
""
],
[
"Dey",
"Dipanjan",
""
],
[
"Joshi",
"Ashok B.",
""
],
[
"Joshi",
"Pankaj S.",
""
],
[
"Patel",
"Vishwa",
""
]
] |
Astrometric observations of S-stars provide a unique opportunity to probe the nature of Sagittarius-A* (Sgr-A*). In view of this, it has become important to understand the nature and behavior of timelike bound trajectories of particles around a massive central object. It is known now that whereas the Schwarzschild black hole does not allow the negative precession for the S-stars, the naked singularity spacetimes can admit the positive as well as negative precession for the bound timelike orbits. In this context, we study the perihelion precession of a test particle in the Kerr spacetime geometry. Considering some approximations, we investigate whether the timelike bound orbits of a test particle in Kerr spacetime can have negative precession. In this paper, we only consider low eccentric timelike equatorial orbits. With these considerations, we find that in Kerr spacetimes, negative precession of timelike bound orbits is not allowed.
|
gr-qc/0101069
|
Jerzy Lewandowski
|
Marcin Bobie\'nski, Jerzy Lewandowski and Mariusz Mroczek
|
A 2-Surface Quantization of the Lorentzian Gravity
|
QG1-a session of MG9
| null |
10.1142/9789812777386_0215
| null |
gr-qc
| null |
This is a contribution to the MG9 session QG1-a. A new quantum representation
for the Lorentzian gravity is created from the Pullin vaccum by the operators
assigned to 2-complexes. The representation uses the original, spinorial
Ashtekar variables, the reality conditions are well posed and Thiemann's
Hamiltonian is well defined. The results on the existence of a suitable Hilbert
product are partial. They were derived in collaboration with Abhay Ashtekar.
|
[
{
"created": "Wed, 17 Jan 2001 12:11:36 GMT",
"version": "v1"
}
] |
2017-08-23
|
[
[
"Bobieński",
"Marcin",
""
],
[
"Lewandowski",
"Jerzy",
""
],
[
"Mroczek",
"Mariusz",
""
]
] |
This is a contribution to the MG9 session QG1-a. A new quantum representation for the Lorentzian gravity is created from the Pullin vaccum by the operators assigned to 2-complexes. The representation uses the original, spinorial Ashtekar variables, the reality conditions are well posed and Thiemann's Hamiltonian is well defined. The results on the existence of a suitable Hilbert product are partial. They were derived in collaboration with Abhay Ashtekar.
|
gr-qc/0002052
|
Chamula Marian
|
V. Skalsky
|
The gauge factor increase and the hypothetical emerging of the matter
objects on the horizon in the standard model of universe
|
7 pages
|
Vedecke prace Materialovo-technologickej fakulty Slovenskej
technickej univerzity v Bratislave so sidlom v Trnave, vol. 6, Slovak
University of Technology Press, Bratislava 2000, ISBN 80-227-1424-0, pp.
119-124
| null | null |
gr-qc
| null |
In the standard model of universe the increase in mass of our observed
expansive and isotropic relativistic Universe is explained by the hypothetical
assumption of matter objects emerging on the horizon (of the most remote
visibility). However, the mathematical-physical analysis of the increase of
Universe gauge factor shows that this hypothetical assumption is non-compatible
with the variants of the standard model of universe by which - according to the
standard model of universe - can be described the expansive evolution of the
Universe.
|
[
{
"created": "Tue, 15 Feb 2000 15:09:12 GMT",
"version": "v1"
},
{
"created": "Mon, 25 Sep 2000 21:15:08 GMT",
"version": "v2"
}
] |
2008-12-19
|
[
[
"Skalsky",
"V.",
""
]
] |
In the standard model of universe the increase in mass of our observed expansive and isotropic relativistic Universe is explained by the hypothetical assumption of matter objects emerging on the horizon (of the most remote visibility). However, the mathematical-physical analysis of the increase of Universe gauge factor shows that this hypothetical assumption is non-compatible with the variants of the standard model of universe by which - according to the standard model of universe - can be described the expansive evolution of the Universe.
|
0809.0375
|
Neven Bilic
|
Neven Bilic, Gary B. Tupper, and Raoul D. Viollier
|
Cosmological tachyon condensation
|
22 pages, 3 figures, title changed, typos corrected, accepted in
Phys. Rev. D
|
Phys.Rev.D80:023515,2009
|
10.1103/PhysRevD.80.023515
| null |
gr-qc astro-ph hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We consider the prospects for dark matter/energy unification in k-essence
type theories. General mappings are established between the k-essence scalar
field, the hydrodynamic and braneworld descriptions. We develop an extension of
the general relativistic dust model that incorporates the effects of both
pressure and the associated acoustic horizon. Applying this to a tachyon model,
we show that this inhomogeneous "variable Chaplygin gas" does evolve into a
mixed system containing cold dark matter like gravitational condensate in
significant quantities. Our methods can be applied to any dark energy model as
well as to mixtures of dark energy and traditional dark matter.
|
[
{
"created": "Tue, 2 Sep 2008 08:45:39 GMT",
"version": "v1"
},
{
"created": "Sat, 27 Sep 2008 16:53:47 GMT",
"version": "v2"
},
{
"created": "Thu, 26 Mar 2009 08:39:48 GMT",
"version": "v3"
},
{
"created": "Thu, 9 Jul 2009 10:50:23 GMT",
"version": "v4"
}
] |
2009-08-11
|
[
[
"Bilic",
"Neven",
""
],
[
"Tupper",
"Gary B.",
""
],
[
"Viollier",
"Raoul D.",
""
]
] |
We consider the prospects for dark matter/energy unification in k-essence type theories. General mappings are established between the k-essence scalar field, the hydrodynamic and braneworld descriptions. We develop an extension of the general relativistic dust model that incorporates the effects of both pressure and the associated acoustic horizon. Applying this to a tachyon model, we show that this inhomogeneous "variable Chaplygin gas" does evolve into a mixed system containing cold dark matter like gravitational condensate in significant quantities. Our methods can be applied to any dark energy model as well as to mixtures of dark energy and traditional dark matter.
|
1812.01854
|
Liu Zhao
|
Chuanyi Wang and Liu Zhao
|
f(Ricci) gravity
|
12 pages. v2: important corrections and new references. v3: removing
a redundant term in eq. (8) and more references
| null | null | null |
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
f(Ricci) gravity is a special kind of higher curvature gravity whose bulk
Lagrangian density is the trace of a matrix-valued function of the Ricci
tensor. It is shown that, under some mild constraints, f(Ricci) gravity admits
Einstein manifolds as exact vacuum solutions, and can be ghost free around
maximally symmetric Einstein vacua. It is also shown that the entropy for
spherically symmetric black holes in f(Ricci) gravity calculated via Wald's
method and the boundary Noether charge approach proposed by Majhi and
Padmanabhan are in good agreement.
|
[
{
"created": "Wed, 5 Dec 2018 08:29:05 GMT",
"version": "v1"
},
{
"created": "Thu, 6 Dec 2018 03:15:34 GMT",
"version": "v2"
},
{
"created": "Tue, 18 Dec 2018 03:13:28 GMT",
"version": "v3"
}
] |
2018-12-19
|
[
[
"Wang",
"Chuanyi",
""
],
[
"Zhao",
"Liu",
""
]
] |
f(Ricci) gravity is a special kind of higher curvature gravity whose bulk Lagrangian density is the trace of a matrix-valued function of the Ricci tensor. It is shown that, under some mild constraints, f(Ricci) gravity admits Einstein manifolds as exact vacuum solutions, and can be ghost free around maximally symmetric Einstein vacua. It is also shown that the entropy for spherically symmetric black holes in f(Ricci) gravity calculated via Wald's method and the boundary Noether charge approach proposed by Majhi and Padmanabhan are in good agreement.
|
0905.1409
|
Chen Songbai
|
Songbai Chen, Jiliang Jing
|
Quasinormal modes of a black hole in the deformed Ho\v{r}ava-Lifshitz
gravity
|
9 pages, 3 figures and 4 tables
|
Phys.Lett. B687:124-128, 2010
|
10.1016/j.physletb.2010.03.013
| null |
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We study the quasinormal modes of the massless scalar perturbation in the
background of a deformed black hole in the Ho\v{r}ava-Lifshitz gravity with
coupling constant $\lambda=1$. Our results show that the quasinormal
frequencies depend on the parameter in the Ho\v{r}ava-Lifshitz gravity and the
behavior of the quasinormal modes is different from those in the
Reissner-Norstr\"{om} and Einstein-Born-Infeld black hole spacetimes. The
absolute value of imaginary parts is smaller and the scalar perturbations decay
more slowly in the deformed Ho\v{r}ava-Lifshitz black hole spacetime. This
information can help us understand more about the Ho\v{r}ava-Lifshitz gravity.
|
[
{
"created": "Sat, 9 May 2009 13:50:39 GMT",
"version": "v1"
},
{
"created": "Wed, 31 Mar 2010 01:16:59 GMT",
"version": "v2"
}
] |
2015-03-13
|
[
[
"Chen",
"Songbai",
""
],
[
"Jing",
"Jiliang",
""
]
] |
We study the quasinormal modes of the massless scalar perturbation in the background of a deformed black hole in the Ho\v{r}ava-Lifshitz gravity with coupling constant $\lambda=1$. Our results show that the quasinormal frequencies depend on the parameter in the Ho\v{r}ava-Lifshitz gravity and the behavior of the quasinormal modes is different from those in the Reissner-Norstr\"{om} and Einstein-Born-Infeld black hole spacetimes. The absolute value of imaginary parts is smaller and the scalar perturbations decay more slowly in the deformed Ho\v{r}ava-Lifshitz black hole spacetime. This information can help us understand more about the Ho\v{r}ava-Lifshitz gravity.
|
1406.6399
|
Miguel Gustavo de Campos Batista
|
M. Campos
|
The cosmic censorship conjecture in a higher dimensional spacetime with
an interacting vacuum energy
|
16 pages, 3 figures
| null |
10.1007/s10773-015-2813-x
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Presently, the inclusion of the vacuum energy in the energy momentum tensor,
and the inclusion of the extra dimensions in the spacetime, can not be rule out
of the research in gravitation. In this work we study the influence of the
vacuum energy in the collapse process of a stellar fluid, and consequently for
the cosmic censorship conjecture, considering a homogeneous and isotropic
spacetime with arbitrary number of dimensions. We discuss the active
gravitational mass of the black hole formed, where the vacuum energy and the
number of dimensions has a crucial role in the process.
|
[
{
"created": "Tue, 24 Jun 2014 21:52:02 GMT",
"version": "v1"
},
{
"created": "Wed, 28 Jan 2015 23:21:00 GMT",
"version": "v2"
}
] |
2015-10-28
|
[
[
"Campos",
"M.",
""
]
] |
Presently, the inclusion of the vacuum energy in the energy momentum tensor, and the inclusion of the extra dimensions in the spacetime, can not be rule out of the research in gravitation. In this work we study the influence of the vacuum energy in the collapse process of a stellar fluid, and consequently for the cosmic censorship conjecture, considering a homogeneous and isotropic spacetime with arbitrary number of dimensions. We discuss the active gravitational mass of the black hole formed, where the vacuum energy and the number of dimensions has a crucial role in the process.
|
1105.5314
|
Barun Majumder
|
Barun Majumder
|
Quantum Black Hole and the Modified Uncertainty Principle
|
7 pages, comments / criticisms / suggestions welcome. Accepted for
publication in Physics Letters B
|
Phys. Lett. B 701 (2011) 384-387
|
10.1016/j.physletb.2011.05.076
| null |
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Recently Ali et al. (2009) proposed a Generalized Uncertainty Principle (or
GUP) with a linear term in momentum (accompanied by Plank length). Inspired by
this idea we examine the Wheeler-DeWitt equation for a Schwarzschild black hole
with a modified Heisenberg algebra which has a linear term in momentum. We
found that the leading contribution to mass comes from the square root of the
quantum number 'n' which coincides with Bekenstein's proposal. We also found
that the mass of the black hole is directly proportional to the quantum number
'n' when quantum gravity effects are taken into consideration via the modified
uncertainty relation but it reduces the value of mass for a particular value of
the quantum number.
|
[
{
"created": "Thu, 26 May 2011 14:49:03 GMT",
"version": "v1"
},
{
"created": "Tue, 31 May 2011 16:38:21 GMT",
"version": "v2"
}
] |
2011-06-28
|
[
[
"Majumder",
"Barun",
""
]
] |
Recently Ali et al. (2009) proposed a Generalized Uncertainty Principle (or GUP) with a linear term in momentum (accompanied by Plank length). Inspired by this idea we examine the Wheeler-DeWitt equation for a Schwarzschild black hole with a modified Heisenberg algebra which has a linear term in momentum. We found that the leading contribution to mass comes from the square root of the quantum number 'n' which coincides with Bekenstein's proposal. We also found that the mass of the black hole is directly proportional to the quantum number 'n' when quantum gravity effects are taken into consideration via the modified uncertainty relation but it reduces the value of mass for a particular value of the quantum number.
|
1309.7462
|
Shabbir Ghulam
|
Ghulam Shabbir and M. Ramzan
|
Proper curvature symmetry in non-static cylindrically symmetric
Lorentzian manifolds
|
23 pages
| null | null | null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We considered the most general form of non-static cylindrically symmetric
space-times for studying proper curvature symmetry by using the rank of the 6X6
Riemann matrix and direct integration techniques. Studying proper curvature
symmetry in each case of the above space-times it is shown that when the above
space-times admit proper curvature symmetry, they form an infinite dimensional
vector space.
|
[
{
"created": "Sat, 28 Sep 2013 14:05:17 GMT",
"version": "v1"
}
] |
2013-10-01
|
[
[
"Shabbir",
"Ghulam",
""
],
[
"Ramzan",
"M.",
""
]
] |
We considered the most general form of non-static cylindrically symmetric space-times for studying proper curvature symmetry by using the rank of the 6X6 Riemann matrix and direct integration techniques. Studying proper curvature symmetry in each case of the above space-times it is shown that when the above space-times admit proper curvature symmetry, they form an infinite dimensional vector space.
|
2202.10722
|
Yaoguang Zheng
|
Wen-Xiang Chen, Yao-Guang Zheng
|
Analysis on superradiant instability of charged dilaton Black Hole
| null | null | null | null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
In this post, a new variable y($\mu=y\omega$) is added to extend the results
of the above post. We derive a very compact resonance formulation. When y is a
certain limit, the effective potential of the equation exists at the pole, and
the potential well appears outside the event horizon, when ${e}^{-4\alpha \Phi
/(n-1)}\sqrt{\alpha} Q \ll r_{+}\ll 1 / (\frac{4}{n-1}y) $, so charged dilator
black hole is superradiatively unstable at this time.
|
[
{
"created": "Tue, 22 Feb 2022 08:25:58 GMT",
"version": "v1"
}
] |
2022-02-23
|
[
[
"Chen",
"Wen-Xiang",
""
],
[
"Zheng",
"Yao-Guang",
""
]
] |
In this post, a new variable y($\mu=y\omega$) is added to extend the results of the above post. We derive a very compact resonance formulation. When y is a certain limit, the effective potential of the equation exists at the pole, and the potential well appears outside the event horizon, when ${e}^{-4\alpha \Phi /(n-1)}\sqrt{\alpha} Q \ll r_{+}\ll 1 / (\frac{4}{n-1}y) $, so charged dilator black hole is superradiatively unstable at this time.
|
2110.08878
|
Matilde Marcolli
|
Pedro Guicardi and Matilde Marcolli
|
Fractality in Cosmic Topology Models with Spectral Action Gravity
|
55 pages, LaTeX, 14 figures
| null |
10.1088/1361-6382/ac7d8c
| null |
gr-qc math-ph math.MP
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We consider cosmological models based on the spectral action formulation of
(modified) gravity. We analyze the coupled effects, in this model, of the
presence of nontrivial cosmic topology and of fractality in the large scale
structure of spacetime. We show that the topology constrains the possible
fractal structures, and in turn the correction terms to the spectral action due
to fractality distinguish the various cosmic topology candidates, with effects
detectable in a slow-roll inflation scenario, through the power spectra of the
scalar and tensor fluctuations. We also discuss explicit effects of the
presence of fractal structures on the gravitational waves equations.
|
[
{
"created": "Sun, 17 Oct 2021 17:53:43 GMT",
"version": "v1"
}
] |
2022-08-31
|
[
[
"Guicardi",
"Pedro",
""
],
[
"Marcolli",
"Matilde",
""
]
] |
We consider cosmological models based on the spectral action formulation of (modified) gravity. We analyze the coupled effects, in this model, of the presence of nontrivial cosmic topology and of fractality in the large scale structure of spacetime. We show that the topology constrains the possible fractal structures, and in turn the correction terms to the spectral action due to fractality distinguish the various cosmic topology candidates, with effects detectable in a slow-roll inflation scenario, through the power spectra of the scalar and tensor fluctuations. We also discuss explicit effects of the presence of fractal structures on the gravitational waves equations.
|
2406.12510
|
Barry Wardell
|
Barry Wardell, Chris Kavanagh, Sam R. Dolan
|
Sourced metric perturbations of Kerr spacetime in Lorenz gauge
| null | null | null | null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We derive a formalism for solving the Lorenz gauge equations for metric
perturbations of Kerr spacetime sourced by an arbitrary stress-energy tensor.
The metric perturbation is obtained as a sum of differential operators acting
on a set of six scalars, with two of spin-weight $\pm2$, two of spin-weight
$\pm1$, and two of spin-weight $0$. We derive the sourced Teukolsky equations
satisfied by these scalars, with the sources given in terms of differential
operators acting on the stress-energy tensor. The method can be used to obtain
both linear and higher order nonlinear metric perturbations, and it fully
determines the metric perturbation up to a time integral, omitting only static
contributions which must be handled separately.
|
[
{
"created": "Tue, 18 Jun 2024 11:23:35 GMT",
"version": "v1"
}
] |
2024-06-19
|
[
[
"Wardell",
"Barry",
""
],
[
"Kavanagh",
"Chris",
""
],
[
"Dolan",
"Sam R.",
""
]
] |
We derive a formalism for solving the Lorenz gauge equations for metric perturbations of Kerr spacetime sourced by an arbitrary stress-energy tensor. The metric perturbation is obtained as a sum of differential operators acting on a set of six scalars, with two of spin-weight $\pm2$, two of spin-weight $\pm1$, and two of spin-weight $0$. We derive the sourced Teukolsky equations satisfied by these scalars, with the sources given in terms of differential operators acting on the stress-energy tensor. The method can be used to obtain both linear and higher order nonlinear metric perturbations, and it fully determines the metric perturbation up to a time integral, omitting only static contributions which must be handled separately.
|
gr-qc/0502024
|
Stoytcho Yazadjiev
|
Stoytcho S. Yazadjiev
|
Non-asymptotically flat, non-dS/AdS dyonic black holes in dilaton
gravity
|
LaTex, 10 pages; v2 changes in introduction, new references added; v3
new section with n-dimensional solutions is added
|
Class.Quant.Grav. 22 (2005) 3875-3890
|
10.1088/0264-9381/22/19/005
| null |
gr-qc
| null |
We present exact spherically symmetric dyonic black hole solutions in
four-dimensional Einstein-Maxwell-dilaton gravity with Liouville-type
potentials for the dilaton field. These solutions have unusual
asymptotics--they are neither asymptotically flat nor asymptotically (anti-) de
Sitter. The solutions have one or two horizons hiding a curvature singularity
at the origin. A class of topological dyonic black holes with topology of a
torus is also presented. Some basic properties of the black holes are
discussed.
|
[
{
"created": "Sun, 6 Feb 2005 11:15:41 GMT",
"version": "v1"
},
{
"created": "Wed, 16 Feb 2005 15:44:55 GMT",
"version": "v2"
},
{
"created": "Tue, 23 Aug 2005 07:30:19 GMT",
"version": "v3"
}
] |
2009-11-11
|
[
[
"Yazadjiev",
"Stoytcho S.",
""
]
] |
We present exact spherically symmetric dyonic black hole solutions in four-dimensional Einstein-Maxwell-dilaton gravity with Liouville-type potentials for the dilaton field. These solutions have unusual asymptotics--they are neither asymptotically flat nor asymptotically (anti-) de Sitter. The solutions have one or two horizons hiding a curvature singularity at the origin. A class of topological dyonic black holes with topology of a torus is also presented. Some basic properties of the black holes are discussed.
|
2306.07409
|
Peter Hintz
|
Peter Hintz
|
Gluing small black holes along timelike geodesics I: formal solution
|
165 pages, 14 figures. The main change compared to v1 is that
Hypothesis 9.12 from v1 is now proved (Theorem 9.12), and thus we can
unconditionally glue in any subextremal Kerr black hole. Typos corrected,
bibliography updated
| null | null | null |
gr-qc math.AP math.DG
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Given a smooth globally hyperbolic $(3+1)$-dimensional spacetime satisfying
the Einstein vacuum equations (possibly with cosmological constant) and an
inextendible timelike geodesic, we construct a family of metrics depending on a
small parameter $\epsilon>0$ with the following properties. (1) They solve the
Einstein vacuum equations modulo $\mathcal{O}(\epsilon^\infty)$. (2) Away from
the geodesic they tend to the original metric as $\epsilon\to 0$. (3) Their
$\epsilon^{-1}$-rescalings near every point of the geodesic tend to a fixed
subextremal Kerr metric. Our result applies on all spacetimes with noncompact
Cauchy hypersurfaces, and also on spacetimes without nontrivial Killing vector
fields in a neighborhood of a point on the geodesic. If $(M,g)$ is a
neighborhood of the domain of outer communications of subextremal or extremal
Kerr(-anti de~Sitter) spacetime, our metrics model extreme mass ratio mergers
if we choose the timelike geodesic to cross the event horizon.
The metrics which we construct here depend on $\epsilon$ and the (rescaled)
coordinates on the original spacetime in a log-smooth fashion. This in
particular justifies the formal perturbation theoretic setup in work of
Gralla-Wald on gravitational self-force in the case of small black holes.
|
[
{
"created": "Mon, 12 Jun 2023 20:31:39 GMT",
"version": "v1"
},
{
"created": "Tue, 13 Aug 2024 08:24:31 GMT",
"version": "v2"
}
] |
2024-08-14
|
[
[
"Hintz",
"Peter",
""
]
] |
Given a smooth globally hyperbolic $(3+1)$-dimensional spacetime satisfying the Einstein vacuum equations (possibly with cosmological constant) and an inextendible timelike geodesic, we construct a family of metrics depending on a small parameter $\epsilon>0$ with the following properties. (1) They solve the Einstein vacuum equations modulo $\mathcal{O}(\epsilon^\infty)$. (2) Away from the geodesic they tend to the original metric as $\epsilon\to 0$. (3) Their $\epsilon^{-1}$-rescalings near every point of the geodesic tend to a fixed subextremal Kerr metric. Our result applies on all spacetimes with noncompact Cauchy hypersurfaces, and also on spacetimes without nontrivial Killing vector fields in a neighborhood of a point on the geodesic. If $(M,g)$ is a neighborhood of the domain of outer communications of subextremal or extremal Kerr(-anti de~Sitter) spacetime, our metrics model extreme mass ratio mergers if we choose the timelike geodesic to cross the event horizon. The metrics which we construct here depend on $\epsilon$ and the (rescaled) coordinates on the original spacetime in a log-smooth fashion. This in particular justifies the formal perturbation theoretic setup in work of Gralla-Wald on gravitational self-force in the case of small black holes.
|
1311.0443
|
Jose Manuel Velhinho
|
Jeronimo Cortez, Guillermo A. Mena Marugan, Javier Olmedo, Jose M.
Velhinho
|
Unitary evolution as a uniqueness criterion
|
3 pages, contribution for the Proceedings of MG13, Stockholm, 2012
| null | null | null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We briefly review the use of unitary evolution as a uniqueness criterion in
the selection of quantum representations, in the context of scalar fields in
non-stationary situations.
|
[
{
"created": "Sun, 3 Nov 2013 09:30:46 GMT",
"version": "v1"
}
] |
2013-11-05
|
[
[
"Cortez",
"Jeronimo",
""
],
[
"Marugan",
"Guillermo A. Mena",
""
],
[
"Olmedo",
"Javier",
""
],
[
"Velhinho",
"Jose M.",
""
]
] |
We briefly review the use of unitary evolution as a uniqueness criterion in the selection of quantum representations, in the context of scalar fields in non-stationary situations.
|
0902.4133
|
Stanislav Babak
|
Stanislav Babak, Jonathan R. Gair, Edward K. Porter
|
An algorithm for detection of extreme mass ratio inspirals in LISA data
|
14 pages, 4 figures
|
Class.Quant.Grav.26:135004,2009
|
10.1088/0264-9381/26/13/135004
| null |
gr-qc astro-ph.CO
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The gravitational wave signal from a compact object spiralling toward a
massive black hole (MBH) is thought to be one of the most difficult sources to
detect in the LISA data stream. Due to the large parameter space of possible
signals and many orbital cycles spent in the sensitivity band of LISA, it has
been estimated previously that of the order of 10^{35} templates would be
required for a fully coherent search with a template grid, which is
computationally impossible. Here we describe an algorithm based on a
constrained Metropolis-Hastings stochastic search which allows us to find and
accurately estimate parameters of isolated EMRI signals buried in Gaussian
instrumental noise. We illustrate the effectiveness of the algorithm with
results from searches of the Mock LISA Data Challenge round 1B data sets.
|
[
{
"created": "Tue, 24 Feb 2009 12:17:00 GMT",
"version": "v1"
}
] |
2009-06-25
|
[
[
"Babak",
"Stanislav",
""
],
[
"Gair",
"Jonathan R.",
""
],
[
"Porter",
"Edward K.",
""
]
] |
The gravitational wave signal from a compact object spiralling toward a massive black hole (MBH) is thought to be one of the most difficult sources to detect in the LISA data stream. Due to the large parameter space of possible signals and many orbital cycles spent in the sensitivity band of LISA, it has been estimated previously that of the order of 10^{35} templates would be required for a fully coherent search with a template grid, which is computationally impossible. Here we describe an algorithm based on a constrained Metropolis-Hastings stochastic search which allows us to find and accurately estimate parameters of isolated EMRI signals buried in Gaussian instrumental noise. We illustrate the effectiveness of the algorithm with results from searches of the Mock LISA Data Challenge round 1B data sets.
|
2201.10902
|
Gang Wang
|
Gang Wang, Bin Li, Peng Xu, Xilong Fan
|
Charactering instrumental noises and stochastic gravitational wave
signals from combined time-delay interferometry
|
15 pages, 6 figures, accepted for publication in PRD
| null |
10.1103/PhysRevD.106.044054
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
LISA will detect gravitational waves (GWs) in the milli-Hz frequency band in
space. Time-delay interferometry (TDI) is developed to suppress laser frequency
noise beneath the acceleration noise and optical metrology noise. To identify
stochastic GW signals, it would be required to characterize these noise
components entangled in TDI data streams. In this work, we investigate noises
characterization by combining the first-generation TDI channels from Michelson
and Relay configurations. The Michelson channels are helpful to characterize
acceleration noises in the lower frequency band, and the Relay configuration
could effectively resolve optical path noises in the higher frequencies.
Synergy could be achieved from their combination to determine these
instrumental noises. Based on the characterized noises, we further reconstruct
the power spectrum of noise in the selected TDI channel. Two cases are
performed to characterize the spectrum shape of a stochastic GW signal. For a
modeled signal, its parameter(s) could be directly estimated from the TDI data,
and its spectrum could be recovered from the inferred values. And for an
unexpected signal, its spectrum may be recognized and retrieved from
noise-subtracted residual in which its power spectral density surpasses the
noise level.
|
[
{
"created": "Wed, 26 Jan 2022 12:40:53 GMT",
"version": "v1"
},
{
"created": "Sun, 30 Jan 2022 09:09:39 GMT",
"version": "v2"
},
{
"created": "Tue, 26 Jul 2022 14:58:49 GMT",
"version": "v3"
},
{
"created": "Sun, 28 Aug 2022 02:46:43 GMT",
"version": "v4"
}
] |
2022-08-30
|
[
[
"Wang",
"Gang",
""
],
[
"Li",
"Bin",
""
],
[
"Xu",
"Peng",
""
],
[
"Fan",
"Xilong",
""
]
] |
LISA will detect gravitational waves (GWs) in the milli-Hz frequency band in space. Time-delay interferometry (TDI) is developed to suppress laser frequency noise beneath the acceleration noise and optical metrology noise. To identify stochastic GW signals, it would be required to characterize these noise components entangled in TDI data streams. In this work, we investigate noises characterization by combining the first-generation TDI channels from Michelson and Relay configurations. The Michelson channels are helpful to characterize acceleration noises in the lower frequency band, and the Relay configuration could effectively resolve optical path noises in the higher frequencies. Synergy could be achieved from their combination to determine these instrumental noises. Based on the characterized noises, we further reconstruct the power spectrum of noise in the selected TDI channel. Two cases are performed to characterize the spectrum shape of a stochastic GW signal. For a modeled signal, its parameter(s) could be directly estimated from the TDI data, and its spectrum could be recovered from the inferred values. And for an unexpected signal, its spectrum may be recognized and retrieved from noise-subtracted residual in which its power spectral density surpasses the noise level.
|
gr-qc/9509050
|
Gerard 't Hooft
|
G. 't Hooft
|
Quantum information and information loss in General Relativity
|
Elaborated lecture notes for ISQM-Tokyo'95. 15 pages Plain TeX, 3
Figures
| null | null |
THU-95/22
|
gr-qc
| null |
When it comes to performing thought experiments with black holes,
Einstein-Bohr like discussions have to be re-opened. For instance one can ask
what happens to the quantum state of a black hole when the wave function of a
single ingoing particle is replaced by an other one that is orthogonal to the
first, while keeping the total energy and momentum unaffected. Observers at
$t\rightarrow\infty$ will not notice any difference, or so it seems in certain
calculational schemes.
If one argues that this cannot be correct for the complete theory because a
black hole should behave in accordance with conventional quantum mechanics,
implying a unitary evolution, one is forced to believe that local quantum field
theory near the black hole horizon is very different from what had hitherto
been accepted. This would give us very valuable information concerning physics
in the Planck length region, notably a mathematical structure very close to
that of super string theory, but it does lead to conceptual difficulties.
An approach that is somewhat related to this is to suspect a breakdown of
General Relativity for quantum mechanical systems. It is to some extent
unavoidable that Hilbert space is not invariant under general coordinate
transformations because such transformations add and remove some states.
Finally the cosmological constant problem also suggests that flat space-time
has some special significance in a quantum theory. We suggest that a new
causality principle could lead to further clues on how to handle this problem.
|
[
{
"created": "Tue, 26 Sep 1995 16:37:30 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Hooft",
"G. 't",
""
]
] |
When it comes to performing thought experiments with black holes, Einstein-Bohr like discussions have to be re-opened. For instance one can ask what happens to the quantum state of a black hole when the wave function of a single ingoing particle is replaced by an other one that is orthogonal to the first, while keeping the total energy and momentum unaffected. Observers at $t\rightarrow\infty$ will not notice any difference, or so it seems in certain calculational schemes. If one argues that this cannot be correct for the complete theory because a black hole should behave in accordance with conventional quantum mechanics, implying a unitary evolution, one is forced to believe that local quantum field theory near the black hole horizon is very different from what had hitherto been accepted. This would give us very valuable information concerning physics in the Planck length region, notably a mathematical structure very close to that of super string theory, but it does lead to conceptual difficulties. An approach that is somewhat related to this is to suspect a breakdown of General Relativity for quantum mechanical systems. It is to some extent unavoidable that Hilbert space is not invariant under general coordinate transformations because such transformations add and remove some states. Finally the cosmological constant problem also suggests that flat space-time has some special significance in a quantum theory. We suggest that a new causality principle could lead to further clues on how to handle this problem.
|
1806.01753
|
Lavinia Heisenberg
|
Jose Beltran Jimenez and Lavinia Heisenberg
|
Non-trivial gravitational waves and structure formation phenomenology
from dark energy
|
11 pages, typos corrected and references added
| null |
10.1088/1475-7516/2018/09/035
| null |
gr-qc astro-ph.CO hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The detection of the GW170817/GRB170817A event improved the constraints on
the propagation speed of gravitational waves, thus placing possible variations
caused by dark energy under restraint. For models based on scalar fields
belonging to the family of Horndeski Lagrangians, non-minimal derivative
couplings are now severely constrained, entailing a substantially limited
phenomenology. In this work we want to stress that there is still a plethora of
dark energy models that get around this obstacle while still providing
interesting phenomenologies able to distinguish them from the standard
cosmology. We focus on a class involving vector fields as a proxy, but our
discussion is extensible to a broader class of models. In particular, we show
the possibility of having a non-minimal derivative coupling giving a
non-trivial effect on scalar modes without affecting gravitational waves and
the possibility of having a second tensor mode that can oscillate into
gravitational waves. We also present a novel class of configurations breaking
rotational invariance but with an energy-momentum tensor that is isotropic
on-shell. This peculiar feature makes the scalar and vector sectors of the
perturbations mix so that, even in a perfectly isotropic background cosmology,
preferred direction effects can appear in the perturbations. We also comment on
models that give rise to isotropic solutions when averaging over rapid
oscillations of the vector fields. The explored models are classified according
to distinctive field configurations that provide inequivalent realisations of
the Cosmological Principle.
|
[
{
"created": "Tue, 5 Jun 2018 15:42:41 GMT",
"version": "v1"
},
{
"created": "Fri, 8 Jun 2018 13:04:28 GMT",
"version": "v2"
}
] |
2018-10-03
|
[
[
"Jimenez",
"Jose Beltran",
""
],
[
"Heisenberg",
"Lavinia",
""
]
] |
The detection of the GW170817/GRB170817A event improved the constraints on the propagation speed of gravitational waves, thus placing possible variations caused by dark energy under restraint. For models based on scalar fields belonging to the family of Horndeski Lagrangians, non-minimal derivative couplings are now severely constrained, entailing a substantially limited phenomenology. In this work we want to stress that there is still a plethora of dark energy models that get around this obstacle while still providing interesting phenomenologies able to distinguish them from the standard cosmology. We focus on a class involving vector fields as a proxy, but our discussion is extensible to a broader class of models. In particular, we show the possibility of having a non-minimal derivative coupling giving a non-trivial effect on scalar modes without affecting gravitational waves and the possibility of having a second tensor mode that can oscillate into gravitational waves. We also present a novel class of configurations breaking rotational invariance but with an energy-momentum tensor that is isotropic on-shell. This peculiar feature makes the scalar and vector sectors of the perturbations mix so that, even in a perfectly isotropic background cosmology, preferred direction effects can appear in the perturbations. We also comment on models that give rise to isotropic solutions when averaging over rapid oscillations of the vector fields. The explored models are classified according to distinctive field configurations that provide inequivalent realisations of the Cosmological Principle.
|
2011.03848
|
Arkady A. Popov
|
Sergey G. Rubin, Arkadiy Popov, P. M. Petryakova
|
Gravity with Higher Derivatives in D-Dimensions
|
22 pages, 9 figures, this article belongs to the Special Issue
Selected Papers from the 17th Russian Gravitational Conference -
International Conference on Gravity, Cosmology and Astrophysics (RUSGRAV-17)
|
Universe 2020, 6, 187
|
10.3390/universe6100187
| null |
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The aim of this review is to discuss the ways to obtain results based on
gravity with higher derivatives in D-dimensional world. We considered the
following ways: (1) reduction to scalar tensor gravity, (2) direct solution of
the equations of motion, (3) derivation of approximate equations in the
presence of a small parameter in the system, and (4) the method of test
functions. Some applications are presented to illustrate each method. The
unification of two necessary elements of a future theory is also kept in mind -
the extra dimensions and the extended form of the gravity.
|
[
{
"created": "Sat, 7 Nov 2020 20:57:19 GMT",
"version": "v1"
}
] |
2023-04-20
|
[
[
"Rubin",
"Sergey G.",
""
],
[
"Popov",
"Arkadiy",
""
],
[
"Petryakova",
"P. M.",
""
]
] |
The aim of this review is to discuss the ways to obtain results based on gravity with higher derivatives in D-dimensional world. We considered the following ways: (1) reduction to scalar tensor gravity, (2) direct solution of the equations of motion, (3) derivation of approximate equations in the presence of a small parameter in the system, and (4) the method of test functions. Some applications are presented to illustrate each method. The unification of two necessary elements of a future theory is also kept in mind - the extra dimensions and the extended form of the gravity.
|
gr-qc/0004061
|
Jljing
|
Jiliang Jing, Mu-Lin Yan
|
Entropies of Rotating Charged Black Holes from Conformal Field Theory at
Killing Horizons
|
12 pages, no figure, RevTex
|
Phys.Rev. D62 (2000) 104013
|
10.1103/PhysRevD.62.104013
| null |
gr-qc hep-th
| null |
The covariant phase technique is used to compute the constraint algebra of
the stationary axisymmetric charged black hole. A standard Virasoro subalgebra
with corresponding central charge is constructed at a Killing horizon with
Carlip's boundary conditions. For the Kerr-Newman black hole and the
Kerr-Newman-AdS black hole, the density of states determined by conformal
fields theory methods yields the statistical entropy which agrees with the
Bekenstein-Hawking entropy.
|
[
{
"created": "Wed, 19 Apr 2000 14:23:08 GMT",
"version": "v1"
},
{
"created": "Wed, 24 May 2000 08:19:53 GMT",
"version": "v2"
}
] |
2009-10-31
|
[
[
"Jing",
"Jiliang",
""
],
[
"Yan",
"Mu-Lin",
""
]
] |
The covariant phase technique is used to compute the constraint algebra of the stationary axisymmetric charged black hole. A standard Virasoro subalgebra with corresponding central charge is constructed at a Killing horizon with Carlip's boundary conditions. For the Kerr-Newman black hole and the Kerr-Newman-AdS black hole, the density of states determined by conformal fields theory methods yields the statistical entropy which agrees with the Bekenstein-Hawking entropy.
|
2302.02734
|
Masahiko Taniguchi
|
Tomohiro Inagaki and Masahiko Taniguchi
|
Scalar Mode Quadrupole Radiation from Astronomical Sources in $F(R)$
Modified Gravity
|
16pages, 2figures
| null |
10.1103/PhysRevD.108.024003
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We investigate the scalar mode quadrupole radiation of gravitational waves in
$F(R)$ modified gravity. In $F(R)$ gravity a massive scalar mode appears in the
gravitational waves.
We find explicit expressions for the quadrupole radiation and the energy
current of the scalar mode in general $F(R)$ gravity models.
We consider a binary star and a bouncing star as astronomical sources of the
gravitational waves and calculate the quadrupole radiation of the scalar and
tensor modes.
The scalar mode radiates under spherically symmetric conditions, but the
tensor modes do not.
The scalar mode mass is estimated for some typical energy scales. We show a
possibility to detect the scalar mode in the future gravitational waves
observation.
|
[
{
"created": "Mon, 6 Feb 2023 12:20:34 GMT",
"version": "v1"
}
] |
2023-07-19
|
[
[
"Inagaki",
"Tomohiro",
""
],
[
"Taniguchi",
"Masahiko",
""
]
] |
We investigate the scalar mode quadrupole radiation of gravitational waves in $F(R)$ modified gravity. In $F(R)$ gravity a massive scalar mode appears in the gravitational waves. We find explicit expressions for the quadrupole radiation and the energy current of the scalar mode in general $F(R)$ gravity models. We consider a binary star and a bouncing star as astronomical sources of the gravitational waves and calculate the quadrupole radiation of the scalar and tensor modes. The scalar mode radiates under spherically symmetric conditions, but the tensor modes do not. The scalar mode mass is estimated for some typical energy scales. We show a possibility to detect the scalar mode in the future gravitational waves observation.
|
1106.5152
|
Fernando Oscar Minotti
|
F. O. Minotti
|
Scalar-tensor theory with enhanced gravitational effects
|
8 pages
| null | null | null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
It is shown that a Brans-Dicke scalar-tensor gravitational theory, which also
includes Bekenstein's kind of interaction between the Maxwell and scalar
fields, has a particular kind of solutions with highly enhanced gravitational
effects as compared with General Relativity, prone to laboratory tests.
|
[
{
"created": "Sat, 25 Jun 2011 17:47:24 GMT",
"version": "v1"
},
{
"created": "Wed, 21 Dec 2011 15:11:08 GMT",
"version": "v2"
}
] |
2011-12-22
|
[
[
"Minotti",
"F. O.",
""
]
] |
It is shown that a Brans-Dicke scalar-tensor gravitational theory, which also includes Bekenstein's kind of interaction between the Maxwell and scalar fields, has a particular kind of solutions with highly enhanced gravitational effects as compared with General Relativity, prone to laboratory tests.
|
gr-qc/0012046
|
Dmitri Vassiliev
|
Alastair D. King and Dmitri Vassiliev
|
Torsion waves in metric-affine field theory
|
12 pages, LaTeX2e
|
Class.Quant.Grav. 18 (2001) 2317-2330
|
10.1088/0264-9381/18/12/307
| null |
gr-qc
| null |
The approach of metric-affine field theory is to define spacetime as a real
oriented 4-manifold equipped with a metric and an affine connection. The 10
independent components of the metric tensor and the 64 connection coefficients
are the unknowns of the theory. We write the Yang-Mills action for the affine
connection and vary it both with respect to the metric and the connection. We
find a family of spacetimes which are stationary points. These spacetimes are
waves of torsion in Minkowski space. We then find a special subfamily of
spacetimes with zero Ricci curvature; the latter condition is the Einstein
equation describing the absence of sources of gravitation. A detailed
examination of this special subfamily suggests the possibility of using it to
model the neutrino. Our model naturally contains only two distinct types of
particles which may be identified with left-handed neutrinos and right-handed
antineutrinos.
|
[
{
"created": "Wed, 13 Dec 2000 08:30:42 GMT",
"version": "v1"
}
] |
2009-10-31
|
[
[
"King",
"Alastair D.",
""
],
[
"Vassiliev",
"Dmitri",
""
]
] |
The approach of metric-affine field theory is to define spacetime as a real oriented 4-manifold equipped with a metric and an affine connection. The 10 independent components of the metric tensor and the 64 connection coefficients are the unknowns of the theory. We write the Yang-Mills action for the affine connection and vary it both with respect to the metric and the connection. We find a family of spacetimes which are stationary points. These spacetimes are waves of torsion in Minkowski space. We then find a special subfamily of spacetimes with zero Ricci curvature; the latter condition is the Einstein equation describing the absence of sources of gravitation. A detailed examination of this special subfamily suggests the possibility of using it to model the neutrino. Our model naturally contains only two distinct types of particles which may be identified with left-handed neutrinos and right-handed antineutrinos.
|
1911.00047
|
Peng Zhao
|
David Hilditch, Juan A. Valiente Kroon and Peng Zhao
|
Revisiting the characteristic initial value problem for the vacuum
Einstein field equations
|
58 pages, 4 figures
| null |
10.1007/s10714-020-02747-2
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Using the Newman-Penrose formalism we study the characteristic initial value
problem in vacuum General Relativity. We work in a gauge suggested by Stewart,
and following the strategy taken in the work of Luk, demonstrate local
existence of solutions in a neighbourhood of the set on which data are given.
These data are given on intersecting null hypersurfaces. Existence near their
intersection is achieved by combining the observation that the field equations
are symmetric hyperbolic in this gauge with the results of Rendall. To obtain
existence all the way along the null-hypersurfaces themselves, a bootstrap
argument involving the Newman-Penrose variables is performed.
|
[
{
"created": "Thu, 31 Oct 2019 18:34:35 GMT",
"version": "v1"
}
] |
2020-10-14
|
[
[
"Hilditch",
"David",
""
],
[
"Kroon",
"Juan A. Valiente",
""
],
[
"Zhao",
"Peng",
""
]
] |
Using the Newman-Penrose formalism we study the characteristic initial value problem in vacuum General Relativity. We work in a gauge suggested by Stewart, and following the strategy taken in the work of Luk, demonstrate local existence of solutions in a neighbourhood of the set on which data are given. These data are given on intersecting null hypersurfaces. Existence near their intersection is achieved by combining the observation that the field equations are symmetric hyperbolic in this gauge with the results of Rendall. To obtain existence all the way along the null-hypersurfaces themselves, a bootstrap argument involving the Newman-Penrose variables is performed.
|
1410.4671
|
Vladimir S. Manko
|
H. Garc\'ia-Compe\'an and V. S. Manko
|
Comment on "Global Structure of the Kerr Family of Gravitational Fields"
|
4 pages, no figures
| null | null | null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We comment on the role of the Cartesian-type Kerr-Schild coordinates in
developing a faulty maximal extension of the Kerr-Newman solution in the
well-known paper of Carter.
|
[
{
"created": "Fri, 17 Oct 2014 09:28:31 GMT",
"version": "v1"
}
] |
2014-10-20
|
[
[
"García-Compeán",
"H.",
""
],
[
"Manko",
"V. S.",
""
]
] |
We comment on the role of the Cartesian-type Kerr-Schild coordinates in developing a faulty maximal extension of the Kerr-Newman solution in the well-known paper of Carter.
|
1307.3640
|
Marco Crisostomi
|
Eugeny Babichev and Marco Crisostomi
|
Restoring General Relativity in massive bi-gravity theory
|
18 pages, 10 figures, typos corrected, version published in PRD
|
Phys. Rev. D 88, 084002 (2013)
|
10.1103/PhysRevD.88.084002
|
LPT-ORSAY-13-72
|
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We study static spherically symmetric solutions of massive bi-gravity theory,
free from the Boulware-Deser ghost. We show the recovery of General Relativity
via the Vainshtein mechanism, in the weak limit of the physical metric. We find
a single polynomial equation determining the behavior of the solution for
distances smaller than the inverse graviton mass. This equation is generically
of the seventh order, while for a specific choice of the parameters of the
theory it can be reduced to lower orders. The solution is analytic in different
regimes: for distances below the Vainshtein radius (where General Relativity is
recovered), and in the opposite regime, beyond the Vainshtein radius, where the
solution approaches the flat metric.
|
[
{
"created": "Sat, 13 Jul 2013 10:39:16 GMT",
"version": "v1"
},
{
"created": "Fri, 2 Aug 2013 09:45:49 GMT",
"version": "v2"
},
{
"created": "Thu, 21 Nov 2013 08:58:56 GMT",
"version": "v3"
}
] |
2013-11-22
|
[
[
"Babichev",
"Eugeny",
""
],
[
"Crisostomi",
"Marco",
""
]
] |
We study static spherically symmetric solutions of massive bi-gravity theory, free from the Boulware-Deser ghost. We show the recovery of General Relativity via the Vainshtein mechanism, in the weak limit of the physical metric. We find a single polynomial equation determining the behavior of the solution for distances smaller than the inverse graviton mass. This equation is generically of the seventh order, while for a specific choice of the parameters of the theory it can be reduced to lower orders. The solution is analytic in different regimes: for distances below the Vainshtein radius (where General Relativity is recovered), and in the opposite regime, beyond the Vainshtein radius, where the solution approaches the flat metric.
|
2212.10290
|
Marco Galoppo
|
Marco Galoppo, Sergio Luigi Cacciatori, Vittorio Gorini and Mariarosa
Mazza
|
Equatorial Lensing in the Balasin-Grumiller Galaxy Model
|
19 pages and 6 figures
| null | null | null |
gr-qc
|
http://creativecommons.org/licenses/by/4.0/
|
The Balasin-Grumiller model has been the first model employed as an attempt
towards providing a fully general relativistic description of the dynamics of a
disc galaxy. In this paper, we compute the equatorial gravitational lensing
observables of the model. Indeed, our purpose is to investigate the role that
gravitational lensing plays as an observable in distinguishing between the
state-of-the-art galaxy models and the fully general relativistic ones, with
the latter stressing the role of frame-dragging and hence conceivably pointing
to a possible re-weighting of the dark matter content of disc galaxies. We
obtain for the Balasin-Grumiller model the exact formula for the bending angle
of light and we provide a corresponding estimate for the time delay between
images in the equatorial plane. For a reasonable choice for the values of the
parameters of the solution (bulge and scale radiuses, and average rotational
star speeds), the values that we obtain for the bending angle are in agreement
with those observed for typical disc galaxies. On the other hand, the
calculated time delay, which is directly tied to the frame-dragging generated
by the angular momentum of the galaxy, turns out to be some orders of magnitude
larger than the ones measured for the class of galaxies that the
Balasin-Grumiller model would claim to describe. We believe this abnormal
discrepancy to be due to the very nature of the Balasin-Grumiller model.
Namely, it being rigidly rotating, hence providing an unphysical amount of
frame-dragging. Therefore, we conclude that, in spite of its simplicity and its
unquestionable didactical value, the Balasin-Grumiller model is far too crude
to provide an instrument for a reliable general relativistic description of a
disc galaxy and that further work in the fully general relativistic modelling
of galaxies is required to reach a satisfactory stage.
|
[
{
"created": "Tue, 20 Dec 2022 14:34:35 GMT",
"version": "v1"
},
{
"created": "Sat, 19 Aug 2023 02:31:07 GMT",
"version": "v2"
}
] |
2023-08-22
|
[
[
"Galoppo",
"Marco",
""
],
[
"Cacciatori",
"Sergio Luigi",
""
],
[
"Gorini",
"Vittorio",
""
],
[
"Mazza",
"Mariarosa",
""
]
] |
The Balasin-Grumiller model has been the first model employed as an attempt towards providing a fully general relativistic description of the dynamics of a disc galaxy. In this paper, we compute the equatorial gravitational lensing observables of the model. Indeed, our purpose is to investigate the role that gravitational lensing plays as an observable in distinguishing between the state-of-the-art galaxy models and the fully general relativistic ones, with the latter stressing the role of frame-dragging and hence conceivably pointing to a possible re-weighting of the dark matter content of disc galaxies. We obtain for the Balasin-Grumiller model the exact formula for the bending angle of light and we provide a corresponding estimate for the time delay between images in the equatorial plane. For a reasonable choice for the values of the parameters of the solution (bulge and scale radiuses, and average rotational star speeds), the values that we obtain for the bending angle are in agreement with those observed for typical disc galaxies. On the other hand, the calculated time delay, which is directly tied to the frame-dragging generated by the angular momentum of the galaxy, turns out to be some orders of magnitude larger than the ones measured for the class of galaxies that the Balasin-Grumiller model would claim to describe. We believe this abnormal discrepancy to be due to the very nature of the Balasin-Grumiller model. Namely, it being rigidly rotating, hence providing an unphysical amount of frame-dragging. Therefore, we conclude that, in spite of its simplicity and its unquestionable didactical value, the Balasin-Grumiller model is far too crude to provide an instrument for a reliable general relativistic description of a disc galaxy and that further work in the fully general relativistic modelling of galaxies is required to reach a satisfactory stage.
|
1201.3171
|
Muhammad Sharif
|
M. Sharif and Wajiha Javed
|
Black Hole Evaporation in a Noncommutative Charged Vaidya Model
|
25 pages, 36 figures, accepted for publication in J. Exp. Theor. Phys
|
J. Exp. Theor. Phys. 114(2012)933-945
|
10.1134/S1063776112050123
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The aim of this paper is to study the black hole evaporation and Hawking
radiation for a noncommutative charged Vaidya black hole. For this purpose, we
determine spherically symmetric charged Vaidya model and then formulate a
noncommutative Reissner-Nordstr$\ddot{o}$m-like solution of this model which
leads to an exact $(t-r)$ dependent metric. The behavior of temporal component
of this metric and the corresponding Hawking temperature is investigated. The
results are shown in the form of graphs. Further, we examine the tunneling
process of the charged massive particles through the quantum horizon. It is
found that the tunneling amplitude is modified due to noncommutativity. Also,
it turns out that black hole evaporates completely in the limits of large time
and horizon radius. The effect of charge is to reduce the temperature from
maximum value to zero. It is mentioned here that the final stage of black hole
evaporation turns out to be a naked singularity.
|
[
{
"created": "Mon, 16 Jan 2012 07:56:23 GMT",
"version": "v1"
}
] |
2015-06-03
|
[
[
"Sharif",
"M.",
""
],
[
"Javed",
"Wajiha",
""
]
] |
The aim of this paper is to study the black hole evaporation and Hawking radiation for a noncommutative charged Vaidya black hole. For this purpose, we determine spherically symmetric charged Vaidya model and then formulate a noncommutative Reissner-Nordstr$\ddot{o}$m-like solution of this model which leads to an exact $(t-r)$ dependent metric. The behavior of temporal component of this metric and the corresponding Hawking temperature is investigated. The results are shown in the form of graphs. Further, we examine the tunneling process of the charged massive particles through the quantum horizon. It is found that the tunneling amplitude is modified due to noncommutativity. Also, it turns out that black hole evaporates completely in the limits of large time and horizon radius. The effect of charge is to reduce the temperature from maximum value to zero. It is mentioned here that the final stage of black hole evaporation turns out to be a naked singularity.
|
1211.6903
|
Keiju Murata Dr
|
Keiju Murata
|
Instability of higher dimensional extreme black holes
|
19 pages
| null |
10.1088/0264-9381/30/7/075002
| null |
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We study linearized gravitational perturbations of extreme black hole
solutions of the vacuum Einstein equation in any number of dimensions. We find
that the equations governing such perturbations can be decoupled at the future
event horizon. Using these equations, we show that transverse derivatives of
certain gauge invariant quantities blow up at late time along the horizon if
the black hole solution satisfies certain conditions. We find that these
conditions are indeed satisfied by many extreme Myers-Perry solutions,
including all such solutions in five dimensions.
|
[
{
"created": "Thu, 29 Nov 2012 13:02:36 GMT",
"version": "v1"
}
] |
2015-06-12
|
[
[
"Murata",
"Keiju",
""
]
] |
We study linearized gravitational perturbations of extreme black hole solutions of the vacuum Einstein equation in any number of dimensions. We find that the equations governing such perturbations can be decoupled at the future event horizon. Using these equations, we show that transverse derivatives of certain gauge invariant quantities blow up at late time along the horizon if the black hole solution satisfies certain conditions. We find that these conditions are indeed satisfied by many extreme Myers-Perry solutions, including all such solutions in five dimensions.
|
1501.07537
|
Joel Franklin
|
J. Franklin, Y. Guo, A. McNutt, A. Morgan
|
The Schrodinger-Newton System with Self-Field Coupling
|
to appear, Class. Quant. Grav
| null |
10.1088/0264-9381/32/6/065010
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We study the Schrodinger-Newton system of equations with the addition of
gravitational field energy sourcing - such additional nonlinearity is to be
expected from a theory of gravity (like general relativity), and its appearance
in this simplified scalar setting (one of Einstein's precursors to general
relativity) leads to significant changes in the spectrum of the
self-gravitating theory. Using an iterative technique, we compare the mass
dependence of the ground state energies of both Schrodinger-Newton and the new,
self-sourced system and find that they are dramatically different. The Bohr
method approach from old quantization provides a qualitative description of the
difference, which comes from the additional nonlinearity introduced in the
self-sourced case. In addition to comparison of ground state energies, we
calculate the transition energy between the ground state and first excited
state to compare emission frequencies between Schrodinger-Newton and the
self-coupled scalar case.
|
[
{
"created": "Thu, 29 Jan 2015 18:28:58 GMT",
"version": "v1"
}
] |
2015-06-23
|
[
[
"Franklin",
"J.",
""
],
[
"Guo",
"Y.",
""
],
[
"McNutt",
"A.",
""
],
[
"Morgan",
"A.",
""
]
] |
We study the Schrodinger-Newton system of equations with the addition of gravitational field energy sourcing - such additional nonlinearity is to be expected from a theory of gravity (like general relativity), and its appearance in this simplified scalar setting (one of Einstein's precursors to general relativity) leads to significant changes in the spectrum of the self-gravitating theory. Using an iterative technique, we compare the mass dependence of the ground state energies of both Schrodinger-Newton and the new, self-sourced system and find that they are dramatically different. The Bohr method approach from old quantization provides a qualitative description of the difference, which comes from the additional nonlinearity introduced in the self-sourced case. In addition to comparison of ground state energies, we calculate the transition energy between the ground state and first excited state to compare emission frequencies between Schrodinger-Newton and the self-coupled scalar case.
|
1906.11859
|
T. Damour
|
Thibault Damour and Vasilisa Nikiforova
|
Spherically symmetric solutions in torsion bigravity
|
28 pages, 3 figures
|
Phys. Rev. D 100, 024065 (2019)
|
10.1103/PhysRevD.100.024065
| null |
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We study spherically symmetric solutions in a four-parameter
Einstein-Cartan-type class of theories. These theories include torsion, as well
as the metric, as dynamical fields, and contain only two physical excitations
(around flat spacetime): a massless spin-2 excitation and a massive spin-2 one
(of mass $ m_2 \equiv \kappa$). They offer a geometric framework (which we
propose to call "torsion bigravity") for a modification of Einstein's theory
that has the same spectrum as bimetric gravity models. We find that the
spherically symmetric solutions of torsion bigravity theories exhibit several
remarkable features: (i) they have the same number of degrees of freedom as
their analogs in ghost-free bimetric gravity theories ( i.e. one less than in
ghost-full bimetric gravity theories); (ii) in the limit of small mass for the
spin-2 field ($ \kappa \to 0$), no inverse powers of $\kappa$ arise at the
first two orders of perturbation theory (contrary to what happens in bimetric
gravity where $1/\kappa^2$ factors arise at linear order, and $1/\kappa^4$ ones
at quadratic order). We numerically construct a high-compactness
(asymptotically flat) star model in torsion bigravity and show that its
geometrical and physical properties are significantly different from those of a
general relativistic star having the same observable Keplerian mass.
|
[
{
"created": "Thu, 27 Jun 2019 18:04:42 GMT",
"version": "v1"
}
] |
2019-08-07
|
[
[
"Damour",
"Thibault",
""
],
[
"Nikiforova",
"Vasilisa",
""
]
] |
We study spherically symmetric solutions in a four-parameter Einstein-Cartan-type class of theories. These theories include torsion, as well as the metric, as dynamical fields, and contain only two physical excitations (around flat spacetime): a massless spin-2 excitation and a massive spin-2 one (of mass $ m_2 \equiv \kappa$). They offer a geometric framework (which we propose to call "torsion bigravity") for a modification of Einstein's theory that has the same spectrum as bimetric gravity models. We find that the spherically symmetric solutions of torsion bigravity theories exhibit several remarkable features: (i) they have the same number of degrees of freedom as their analogs in ghost-free bimetric gravity theories ( i.e. one less than in ghost-full bimetric gravity theories); (ii) in the limit of small mass for the spin-2 field ($ \kappa \to 0$), no inverse powers of $\kappa$ arise at the first two orders of perturbation theory (contrary to what happens in bimetric gravity where $1/\kappa^2$ factors arise at linear order, and $1/\kappa^4$ ones at quadratic order). We numerically construct a high-compactness (asymptotically flat) star model in torsion bigravity and show that its geometrical and physical properties are significantly different from those of a general relativistic star having the same observable Keplerian mass.
|
0811.0558
|
Alexey Toporensky
|
S. A. Pavluchenko and A. V. Toporensky
|
A note on differences between (4+1)- and (5+1)-dimensional anisotropic
cosmology in the presence of the Gauss-Bonnet term
|
9 pages with 3 eps figures; typos corrected, references added; final
version to appear in MPLA
|
Mod.Phys.Lett.A24:513-521,2009
|
10.1142/S0217732309030187
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We investigate a flat anisotropic (5+1)-dimensional cosmological model in the
presence of the Gauss-Bonnet (GB) contribution in addition to usual Einstein
term in the action. We compared it with (4+1)-dimensional case and found a
substantial difference in corresponding cosmological dynamics. This difference
is manifested in the probability of the model to have smooth transition from
GB-term-dominated to Einstein-term-dominated phases--this probability in a
reasonable measure on the initial condition space is almost zero for (4+1) case
and about 60% for (5+1) case. We discuss this difference as well as some
features of the dynamics of the considered model.
|
[
{
"created": "Tue, 4 Nov 2008 17:25:10 GMT",
"version": "v1"
},
{
"created": "Wed, 4 Mar 2009 13:39:24 GMT",
"version": "v2"
}
] |
2009-04-17
|
[
[
"Pavluchenko",
"S. A.",
""
],
[
"Toporensky",
"A. V.",
""
]
] |
We investigate a flat anisotropic (5+1)-dimensional cosmological model in the presence of the Gauss-Bonnet (GB) contribution in addition to usual Einstein term in the action. We compared it with (4+1)-dimensional case and found a substantial difference in corresponding cosmological dynamics. This difference is manifested in the probability of the model to have smooth transition from GB-term-dominated to Einstein-term-dominated phases--this probability in a reasonable measure on the initial condition space is almost zero for (4+1) case and about 60% for (5+1) case. We discuss this difference as well as some features of the dynamics of the considered model.
|
2107.12488
|
Valerio Faraoni
|
Valerio Faraoni, Sonia Jose, and Steve Dussault (Bishop's University)
|
Multi-fluid cosmology in Einstein gravity: analytical solutions
|
Bibliography expanded and typographical errors corrected. Matches the
version to appear in Gen. Relativ. Gravit
| null |
10.1007/s10714-021-02879-z
| null |
gr-qc astro-ph.CO hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We review analytical solutions of the Einstein equations which are expressed
in terms of elementary functions and describe
Friedmann-Lema\^itre-Robertson-Walker universes sourced by multiple (real or
effective) perfect fluids with constant equations of state. Effective fluids
include spatial curvature, the cosmological constant, and scalar fields. We
provide a description with unified notation, explicit and parametric forms of
the solutions, and relations between different expressions present in the
literature. Interesting solutions from a modern point of view include
interacting fluids and scalar fields. Old solutions, integrability conditions,
and solution methods keep being rediscovered, which motivates a review with
modern eyes.
|
[
{
"created": "Mon, 26 Jul 2021 21:28:50 GMT",
"version": "v1"
},
{
"created": "Fri, 5 Nov 2021 18:49:32 GMT",
"version": "v2"
}
] |
2021-12-15
|
[
[
"Faraoni",
"Valerio",
"",
"Bishop's University"
],
[
"Jose",
"Sonia",
"",
"Bishop's University"
],
[
"Dussault",
"Steve",
"",
"Bishop's University"
]
] |
We review analytical solutions of the Einstein equations which are expressed in terms of elementary functions and describe Friedmann-Lema\^itre-Robertson-Walker universes sourced by multiple (real or effective) perfect fluids with constant equations of state. Effective fluids include spatial curvature, the cosmological constant, and scalar fields. We provide a description with unified notation, explicit and parametric forms of the solutions, and relations between different expressions present in the literature. Interesting solutions from a modern point of view include interacting fluids and scalar fields. Old solutions, integrability conditions, and solution methods keep being rediscovered, which motivates a review with modern eyes.
|
2210.02634
|
Amanda Guerrieri
|
Amanda Guerrieri and Mario Novello
|
Photon propagation in a material medium on a curved spacetime
|
21 pages, 1 figure
| null |
10.1088/1361-6382/aca23a
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We consider a nonlinear dielectric medium surrounding a static, charged and
spherically symmetric compact body which gravitational field is driven by
General Relativity (GR). Considering the propagating waves on the dielectric
medium, we describe the trajectory of light as geodesics on an effective
geometry given by Hadamard's discontinuities. We analyze some consequences of
the effective geometry in the propagation of light, with relation to the
predictions of the background gravitational field, that includes corrections on
the geometrical redshift and on the gravitational deflection of light. We show
that the background electromagnetic field polarize the material medium, such
that different polarizations of light are distinguished by different
corrections on these quantities. As a consequence, we have two possible paths
for the trajectory of light in such configuration, that coincide if we turn off
the electromagnetic field or if the permittivity is constant. We show that the
effective metric associated to the negative polarization, for a given
dependence of the dielectric permittivity, is conformally flat.
|
[
{
"created": "Thu, 6 Oct 2022 01:59:11 GMT",
"version": "v1"
}
] |
2022-12-07
|
[
[
"Guerrieri",
"Amanda",
""
],
[
"Novello",
"Mario",
""
]
] |
We consider a nonlinear dielectric medium surrounding a static, charged and spherically symmetric compact body which gravitational field is driven by General Relativity (GR). Considering the propagating waves on the dielectric medium, we describe the trajectory of light as geodesics on an effective geometry given by Hadamard's discontinuities. We analyze some consequences of the effective geometry in the propagation of light, with relation to the predictions of the background gravitational field, that includes corrections on the geometrical redshift and on the gravitational deflection of light. We show that the background electromagnetic field polarize the material medium, such that different polarizations of light are distinguished by different corrections on these quantities. As a consequence, we have two possible paths for the trajectory of light in such configuration, that coincide if we turn off the electromagnetic field or if the permittivity is constant. We show that the effective metric associated to the negative polarization, for a given dependence of the dielectric permittivity, is conformally flat.
|
2103.04468
|
Carl Diether
|
Carl F. Diether, III and Joy Christian
|
Comment on `Relativistic wave-particle duality for spinors'
|
4 page, no figures; Note added to proof
| null | null | null |
gr-qc quant-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
In a recent paper [1], it has been proposed that relativistic wave-particle
duality can be embodied in a relation that shows that the four-velocity of a
particle is proportional to the Dirac four-current. In this note we bring out
some problems with that idea. In particular, we point out that, in line with
existing literature on Einstein-Cartan gravity with torsion, the spin-torsion
term should represent negative energy. Moreover, if what is proposed in Eq.
(20) of [1] is correct, then the spin torsion term would be zero in the rest
frame of the fermion. We suggest a possible resolution of that dilemma.
|
[
{
"created": "Sun, 7 Mar 2021 22:09:55 GMT",
"version": "v1"
},
{
"created": "Thu, 19 Aug 2021 14:20:37 GMT",
"version": "v2"
}
] |
2022-02-13
|
[
[
"Diether",
"Carl F.",
""
],
[
"III",
"",
""
],
[
"Christian",
"Joy",
""
]
] |
In a recent paper [1], it has been proposed that relativistic wave-particle duality can be embodied in a relation that shows that the four-velocity of a particle is proportional to the Dirac four-current. In this note we bring out some problems with that idea. In particular, we point out that, in line with existing literature on Einstein-Cartan gravity with torsion, the spin-torsion term should represent negative energy. Moreover, if what is proposed in Eq. (20) of [1] is correct, then the spin torsion term would be zero in the rest frame of the fermion. We suggest a possible resolution of that dilemma.
|
gr-qc/0612025
|
Johan Hansson
|
Johan Hansson
|
Newtonian Quantum Gravity
| null |
Phys. Essays 23:53,2010
|
10.4006/1.3291188
| null |
gr-qc astro-ph quant-ph
| null |
A Newtonian approach to quantum gravity is studied. At least for weak
gravitational fields it should be a valid approximation. Such an approach could
be used to point out problems and prospects inherent in a more exact theory of
quantum gravity, yet to be discovered. Newtonian quantum gravity, e.g., shows
promise for prohibiting black holes altogether (which would eliminate
singularities and also solve the black hole information paradox), breaks the
equivalence principle of general relativity, and supports non-local
interactions (quantum entanglement). Its predictions should also be testable at
length scales well above the "Planck scale", by high-precision experiments
feasible even with existing technology. As an illustration of the theory, it
turns out that the solar system, superficially, perfectly well can be described
as a quantum gravitational system, provided that the $l$ quantum number has its
maximum value, $n-1$. This results exactly in Kepler's third law. If also the
$m$ quantum number has its maximum value ($\pm l$) the probability density has
a very narrow torus-like form, centered around the classical planetary orbits.
However, as the probability density is independent of the azimuthal angle
$\phi$ there is, from quantum gravity arguments, no reason for planets to be
located in any unique place along the orbit (or even \textit{in} an orbit for
$m \neq \pm l$). This is, in essence, a reflection of the "measurement problem"
inherent in all quantum descriptions.
|
[
{
"created": "Mon, 4 Dec 2006 11:01:44 GMT",
"version": "v1"
}
] |
2011-04-07
|
[
[
"Hansson",
"Johan",
""
]
] |
A Newtonian approach to quantum gravity is studied. At least for weak gravitational fields it should be a valid approximation. Such an approach could be used to point out problems and prospects inherent in a more exact theory of quantum gravity, yet to be discovered. Newtonian quantum gravity, e.g., shows promise for prohibiting black holes altogether (which would eliminate singularities and also solve the black hole information paradox), breaks the equivalence principle of general relativity, and supports non-local interactions (quantum entanglement). Its predictions should also be testable at length scales well above the "Planck scale", by high-precision experiments feasible even with existing technology. As an illustration of the theory, it turns out that the solar system, superficially, perfectly well can be described as a quantum gravitational system, provided that the $l$ quantum number has its maximum value, $n-1$. This results exactly in Kepler's third law. If also the $m$ quantum number has its maximum value ($\pm l$) the probability density has a very narrow torus-like form, centered around the classical planetary orbits. However, as the probability density is independent of the azimuthal angle $\phi$ there is, from quantum gravity arguments, no reason for planets to be located in any unique place along the orbit (or even \textit{in} an orbit for $m \neq \pm l$). This is, in essence, a reflection of the "measurement problem" inherent in all quantum descriptions.
|
1512.08447
|
Paul R. Anderson
|
Alessandro Fabbri, Roberto Balbinot, and Paul R. Anderson
|
Scattering coefficients and gray-body factor for 1D BEC acoustic black
holes: exact results
|
13 pages, 1 figure, Final version, to appear in Phys. Rev. D
|
Phys. Rev. D 93, 064046 (2016)
|
10.1103/PhysRevD.93.064046
| null |
gr-qc cond-mat.quant-gas hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
A complete set of exact analytic solutions to the mode equation is found in
the region exterior to the acoustic horizon for a class of 1D Bose-Einstein
condensate (BEC) acoustic black holes. From these, analytic expressions for the
scattering coefficients and gray-body factor are obtained. The results are used
to verify previous predictions regarding the behaviors of the scattering
coefficients and gray-body factor in the low frequency limit.
|
[
{
"created": "Mon, 28 Dec 2015 16:28:36 GMT",
"version": "v1"
},
{
"created": "Wed, 17 Feb 2016 20:32:00 GMT",
"version": "v2"
}
] |
2016-03-23
|
[
[
"Fabbri",
"Alessandro",
""
],
[
"Balbinot",
"Roberto",
""
],
[
"Anderson",
"Paul R.",
""
]
] |
A complete set of exact analytic solutions to the mode equation is found in the region exterior to the acoustic horizon for a class of 1D Bose-Einstein condensate (BEC) acoustic black holes. From these, analytic expressions for the scattering coefficients and gray-body factor are obtained. The results are used to verify previous predictions regarding the behaviors of the scattering coefficients and gray-body factor in the low frequency limit.
|
2403.10439
|
Praveen Kumar
|
Praveen Kumar, Thomas Dent (IGFAE, Universidade de Santiago de
Compostela)
|
Optimized Search for a Binary Black Hole Merger Population in LIGO-Virgo
O3 Data
|
22 pages, 6 figures, 2 tables
| null | null | null |
gr-qc astro-ph.HE
|
http://creativecommons.org/licenses/by/4.0/
|
Maximizing the number of detections in matched filter searches for compact
binary coalescence (CBC) gravitational wave (GW) signals requires a model of
the source population distribution. In previous searches using the PyCBC
framework, sensitivity to the population of binary black hole (BBH) mergers was
improved by restricting the range of filter template mass ratios and use of a
simple one-dimensional population model. However, this approach does not make
use of our full knowledge of the population and cannot be extended to a full
parameter space search. Here, we introduce a new ranking method, based on
kernel density estimation (KDE) with adaptive bandwidth, to accurately model
the probability distributions of binary source parameters over a template bank,
both for signals and for noise events. We demonstrate this ranking method by
conducting a search over LIGO-Virgo O3 data for BBH with unrestricted mass
ratio, using a signal model derived from previous significant detected events.
We achieve over 10% increase in sensitive volume for a simple power-law
simulated signal population, compared to the previous BBH search.
Correspondingly, with the new ranking, 8 additional candidate events above an
inverse false alarm rate (IFAR) threshold 0.5 yr are identified.
|
[
{
"created": "Fri, 15 Mar 2024 16:24:53 GMT",
"version": "v1"
},
{
"created": "Wed, 24 Apr 2024 15:21:32 GMT",
"version": "v2"
}
] |
2024-04-25
|
[
[
"Kumar",
"Praveen",
"",
"IGFAE, Universidade de Santiago de\n Compostela"
],
[
"Dent",
"Thomas",
"",
"IGFAE, Universidade de Santiago de\n Compostela"
]
] |
Maximizing the number of detections in matched filter searches for compact binary coalescence (CBC) gravitational wave (GW) signals requires a model of the source population distribution. In previous searches using the PyCBC framework, sensitivity to the population of binary black hole (BBH) mergers was improved by restricting the range of filter template mass ratios and use of a simple one-dimensional population model. However, this approach does not make use of our full knowledge of the population and cannot be extended to a full parameter space search. Here, we introduce a new ranking method, based on kernel density estimation (KDE) with adaptive bandwidth, to accurately model the probability distributions of binary source parameters over a template bank, both for signals and for noise events. We demonstrate this ranking method by conducting a search over LIGO-Virgo O3 data for BBH with unrestricted mass ratio, using a signal model derived from previous significant detected events. We achieve over 10% increase in sensitive volume for a simple power-law simulated signal population, compared to the previous BBH search. Correspondingly, with the new ranking, 8 additional candidate events above an inverse false alarm rate (IFAR) threshold 0.5 yr are identified.
|
1112.6391
|
Parampreet Singh
|
Parampreet Singh
|
Curvature invariants, geodesics and the strength of singularities in
Bianchi-I loop quantum cosmology
|
Discussion on a possible existence of a non-singularity theorem
added. To appear in PRD
|
Phys. Rev. D 85, 104011 (2012)
|
10.1103/PhysRevD.85.104011
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We investigate the effects of the underlying quantum geometry in loop quantum
cosmology on spacetime curvature invariants and the extendibility of geodesics
in the Bianchi-I model for matter with a vanishing anisotropic stress. Using
the effective Hamiltonian approach, we find that even though quantum geometric
effects bound the energy density and expansion and shear scalars, divergences
of curvature invariants are potentially possible under special conditions.
However, as in the isotropic models in LQC, these do not necessarily imply a
physical singularity. Analysis of geodesics and strength of such singular
events, point towards a general resolution of all known types of strong
singularities. We illustrate these results for the case of a perfect fluid with
an arbitrary finite equation of state $w > -1$, and show that curvature
invariants turn out to be bounded, leading to the absence of strong
singularities. Unlike classical theory, geodesic evolution does not break down.
We also discuss possible generalizations of sudden singularities which may
arise at a non-vanishing volume, causing a divergence in curvature invariants.
Such finite volume singularities are shown to be weak and harmless.
|
[
{
"created": "Thu, 29 Dec 2011 19:32:42 GMT",
"version": "v1"
},
{
"created": "Wed, 11 Apr 2012 14:26:56 GMT",
"version": "v2"
}
] |
2012-07-05
|
[
[
"Singh",
"Parampreet",
""
]
] |
We investigate the effects of the underlying quantum geometry in loop quantum cosmology on spacetime curvature invariants and the extendibility of geodesics in the Bianchi-I model for matter with a vanishing anisotropic stress. Using the effective Hamiltonian approach, we find that even though quantum geometric effects bound the energy density and expansion and shear scalars, divergences of curvature invariants are potentially possible under special conditions. However, as in the isotropic models in LQC, these do not necessarily imply a physical singularity. Analysis of geodesics and strength of such singular events, point towards a general resolution of all known types of strong singularities. We illustrate these results for the case of a perfect fluid with an arbitrary finite equation of state $w > -1$, and show that curvature invariants turn out to be bounded, leading to the absence of strong singularities. Unlike classical theory, geodesic evolution does not break down. We also discuss possible generalizations of sudden singularities which may arise at a non-vanishing volume, causing a divergence in curvature invariants. Such finite volume singularities are shown to be weak and harmless.
|
1706.07413
|
Steven L. Liebling
|
Steven L. Liebling, Gaurav Khanna
|
Scalar collapse in AdS with an OpenCL open source code
|
6 pages, 3 figures; Updated fixing an incorrect sentence about the
initial data and matching to published version
|
Classical and Quantum Gravity 34, 205012 (2017)
|
10.1088/1361-6382/aa8b43
| null |
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We study the spherically symmetric collapse of a scalar field in anti-de
Sitter spacetime using a newly constructed, open-source code which parallelizes
over heterogeneous architectures using the open standard OpenCL. An open
question for this scenario concerns how to tell, a priori, whether some form of
initial data will be stable or will instead develop under the turbulent
instability into a black hole in the limit of vanishing amplitude. Previous
work suggested the existence of islands of stability around quasiperiodic
solutions, and we use this new code to examine the stability properties of
approximately quasiperiodic solutions which balance energy transfer to higher
modes with energy transfer to lower modes. The evolutions provide some
evidence, though not conclusively, for stability of initial data sufficiently
close to quasiperiodic solutions.
|
[
{
"created": "Thu, 22 Jun 2017 17:39:15 GMT",
"version": "v1"
},
{
"created": "Sat, 30 Sep 2017 17:46:44 GMT",
"version": "v2"
}
] |
2017-10-03
|
[
[
"Liebling",
"Steven L.",
""
],
[
"Khanna",
"Gaurav",
""
]
] |
We study the spherically symmetric collapse of a scalar field in anti-de Sitter spacetime using a newly constructed, open-source code which parallelizes over heterogeneous architectures using the open standard OpenCL. An open question for this scenario concerns how to tell, a priori, whether some form of initial data will be stable or will instead develop under the turbulent instability into a black hole in the limit of vanishing amplitude. Previous work suggested the existence of islands of stability around quasiperiodic solutions, and we use this new code to examine the stability properties of approximately quasiperiodic solutions which balance energy transfer to higher modes with energy transfer to lower modes. The evolutions provide some evidence, though not conclusively, for stability of initial data sufficiently close to quasiperiodic solutions.
|
1603.09443
|
Christine Gruber
|
Christine Gruber, Orlando Luongo and Hernando Quevedo
|
Geometric approaches to the thermodynamics of black holes
|
Reviwew of BH5-session prepared for the MG14 Proceedings
| null | null | null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
In this summary, we present the main topics of the talks presented in the
parallel session "Black holes - 5" of the 14th Marcel Grossmann Meeting held in
Rome, Italy in July 2015. We first present a short review of the main
approaches used to understand thermodynamics by using differential geometry.
Then, we present a brief summary of each presentation, including some general
remarks and comments.
|
[
{
"created": "Thu, 31 Mar 2016 02:44:41 GMT",
"version": "v1"
},
{
"created": "Mon, 30 May 2016 23:02:20 GMT",
"version": "v2"
}
] |
2016-06-01
|
[
[
"Gruber",
"Christine",
""
],
[
"Luongo",
"Orlando",
""
],
[
"Quevedo",
"Hernando",
""
]
] |
In this summary, we present the main topics of the talks presented in the parallel session "Black holes - 5" of the 14th Marcel Grossmann Meeting held in Rome, Italy in July 2015. We first present a short review of the main approaches used to understand thermodynamics by using differential geometry. Then, we present a brief summary of each presentation, including some general remarks and comments.
|
0912.4944
|
Cosimo Bambi
|
Cosimo Bambi
|
Numerical simulations of the accretion process in Kerr space-times with
arbitrary value of the Kerr parameter
|
4 pages, 1 figure. To appear in the proceedings of "JGRG19" (Tokyo,
Japan, 30 November - 4 December 2009)
| null | null |
IPMU09-0164
|
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
According to the Cosmic Censorship Conjecture, all the singularities produced
by the collapsing matter must be hidden behind an event horizon. In 4D general
relativity, this implies that the final product of the collapse is a
Kerr-Newman black hole. Here I consider the possibility that the Cosmic
Censorship Conjecture can be violated. I present the results of some numerical
simulations of the accretion process onto Kerr black holes (objects with event
horizon) and Kerr super-spinars (fast-rotating objects without event horizon).
This is a preliminary study to investigate how the Cosmic Censorship Conjecture
can be tested by astrophysical observations.
|
[
{
"created": "Fri, 25 Dec 2009 07:03:08 GMT",
"version": "v1"
},
{
"created": "Mon, 4 Jan 2010 07:37:15 GMT",
"version": "v2"
}
] |
2010-01-04
|
[
[
"Bambi",
"Cosimo",
""
]
] |
According to the Cosmic Censorship Conjecture, all the singularities produced by the collapsing matter must be hidden behind an event horizon. In 4D general relativity, this implies that the final product of the collapse is a Kerr-Newman black hole. Here I consider the possibility that the Cosmic Censorship Conjecture can be violated. I present the results of some numerical simulations of the accretion process onto Kerr black holes (objects with event horizon) and Kerr super-spinars (fast-rotating objects without event horizon). This is a preliminary study to investigate how the Cosmic Censorship Conjecture can be tested by astrophysical observations.
|
1311.6384
|
Anastasia Golubtsova
|
J.-M. Alimi, A. A. Golubtsova and V. Reverdy
|
Elliptic solutions of generalized Brans-Dicke gravity with a
non-universal coupling
|
24 pages, 3 figures; v2: typos fixed, few remarks and references
added; version to appear in EPJC
| null |
10.1140/epjc/s10052-014-3125-7
|
IGC-13/11
|
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We study a model of the generalized Brans-Dicke gravity presented in both the
Jordan and in the Einstein frames, which are conformally related. We show that
the scalar field equations in the Einstein frame are reduced to the geodesics
equations on the target space of the nonlinear sigma-model. The analytical
solutions in elliptical functions are obtained when the conformal couplings are
given by reciprocal exponential functions. The behavior of the scale factor in
the Jordan frame is studied using numerical computations. For certain
parameters the solutions can describe an accelerated expansion. We also derive
an analytical approximation in exponential functions.
|
[
{
"created": "Mon, 25 Nov 2013 18:02:11 GMT",
"version": "v1"
},
{
"created": "Tue, 7 Oct 2014 13:35:52 GMT",
"version": "v2"
}
] |
2015-06-18
|
[
[
"Alimi",
"J. -M.",
""
],
[
"Golubtsova",
"A. A.",
""
],
[
"Reverdy",
"V.",
""
]
] |
We study a model of the generalized Brans-Dicke gravity presented in both the Jordan and in the Einstein frames, which are conformally related. We show that the scalar field equations in the Einstein frame are reduced to the geodesics equations on the target space of the nonlinear sigma-model. The analytical solutions in elliptical functions are obtained when the conformal couplings are given by reciprocal exponential functions. The behavior of the scale factor in the Jordan frame is studied using numerical computations. For certain parameters the solutions can describe an accelerated expansion. We also derive an analytical approximation in exponential functions.
|
0912.0090
|
Sabine Hossenfelder
|
S. Hossenfelder
|
The Box-Problem in Deformed Special Relativity
|
20 pages, 3 figures
| null | null | null |
gr-qc hep-ph hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We examine the transformation of particle trajectories in models with
deformations of Special Relativity that have an energy-dependent and
observer-independent speed of light. These transformations necessarily imply
that the notion of what constitutes the same space-time event becomes dependent
on the observer's inertial frame. To preserve observer-independence, the such
arising nonlocality should not be in conflict with our knowledge of particle
interactions. This requirement allows us to derive strong bounds on
deformations of Special Relativity and rule out a modification to first order
in energy over the Planck mass.
|
[
{
"created": "Tue, 1 Dec 2009 07:29:43 GMT",
"version": "v1"
}
] |
2009-12-03
|
[
[
"Hossenfelder",
"S.",
""
]
] |
We examine the transformation of particle trajectories in models with deformations of Special Relativity that have an energy-dependent and observer-independent speed of light. These transformations necessarily imply that the notion of what constitutes the same space-time event becomes dependent on the observer's inertial frame. To preserve observer-independence, the such arising nonlocality should not be in conflict with our knowledge of particle interactions. This requirement allows us to derive strong bounds on deformations of Special Relativity and rule out a modification to first order in energy over the Planck mass.
|
gr-qc/0602008
|
Sophie Pireaux Dr
|
S. Pireaux (Observatoire de la Cote d'Azur, Department ARTEMIS,
Grasse, France), J-P. Barriot (Observatoire Midi-Pyrenees, UMR 5562-DTP,
Toulouse, France), P. Rosenblatt (Observatoire Royal de Belgique, Bruxelles,
Belgique)
|
(SC)RMI: A (S)emi-(C)lassical (R)elativistic (M)otion (I)integrator, to
model the orbits of space probes around the Earth and other planets
|
13 pages, 5 eps figures, 1 table, accepted in Acta Astronautica,
presented at the International Astronautical Congress, Vancouver 2004,
reference IAC-04-A.7.08
| null |
10.1016/j.actaastro.2006.04.006
| null |
gr-qc
| null |
Today, the motion of spacecrafts is still described according to the
classical Newtonian equations plus the so-called "relativistic corrections",
computed with the required precision using the Post-(Post-)Newtonian formalism.
The current approach, with the increase of tracking precision (Ka-Band Doppler,
interplanetary lasers) and clock stabilities (atomic fountains) is reaching its
limits in terms of complexity, and is furthermore error prone. In the
appropriate framework of General Relativity, we study a method to numerically
integrate the native relativistic equations of motion for a weak gravitational
field, also taking into account small non-gravitational forces. The latter are
treated as perturbations, in the sense that we assume that both the local
structure of space-time is not modified by these forces, and that the
unperturbed satellite motion follows the geodesics of the local space-time. The
use of a symplectic integrator to compute the unperturbed geodesic motion
insures the constancy of the norm of the proper velocity quadrivector. We
further show how this general relativistic framework relates to the classical
one.
|
[
{
"created": "Thu, 2 Feb 2006 11:32:39 GMT",
"version": "v1"
}
] |
2009-11-11
|
[
[
"Pireaux",
"S.",
"",
"Observatoire de la Cote d'Azur, Department ARTEMIS,\n Grasse, France"
],
[
"Barriot",
"J-P.",
"",
"Observatoire Midi-Pyrenees, UMR 5562-DTP,\n Toulouse, France"
],
[
"Rosenblatt",
"P.",
"",
"Observatoire Royal de Belgique, Bruxelles,\n Belgique"
]
] |
Today, the motion of spacecrafts is still described according to the classical Newtonian equations plus the so-called "relativistic corrections", computed with the required precision using the Post-(Post-)Newtonian formalism. The current approach, with the increase of tracking precision (Ka-Band Doppler, interplanetary lasers) and clock stabilities (atomic fountains) is reaching its limits in terms of complexity, and is furthermore error prone. In the appropriate framework of General Relativity, we study a method to numerically integrate the native relativistic equations of motion for a weak gravitational field, also taking into account small non-gravitational forces. The latter are treated as perturbations, in the sense that we assume that both the local structure of space-time is not modified by these forces, and that the unperturbed satellite motion follows the geodesics of the local space-time. The use of a symplectic integrator to compute the unperturbed geodesic motion insures the constancy of the norm of the proper velocity quadrivector. We further show how this general relativistic framework relates to the classical one.
|
0812.2491
|
M. B. Paranjape
|
Luca Fabbri and M. B. Paranjape
|
Monochromatic plane-fronted waves in conformal gravity are pure gauge
|
5 pages, no figures, version published, substantial changes to the
presentation, conclusions unaltered, title changed
|
Phys.Rev.D83:104046,2011
|
10.1103/PhysRevD.83.104046
|
UdeM-GPP-TH-08-173
|
gr-qc hep-th math-ph math.MP
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We consider plane-fronted, monochromatic gravitational waves on a Minkowski
background, in a conformally invariant theory of general relativity. By this we
mean waves of the form: $g_{\mu\nu}=\eta_{\mu\nu}+\epsilon_{\mu\nu}F(k\cdotx)$,
where $\epsilon_{\mu\nu}$ is a constant polarization tensor, and $k_\mu$ is a
lightlike vector. We also assume the coordinate gauge condition
$|g|-1/4\partial_\tau(|g|1/4g^{\sigma\tau})=0$ which is the conformal analog of
the harmonic gauge condition
$g^{\mu\nu}\Gamma_{\mu\nu}^\sigma=-|g|-1/2\partial_\tau(|g|1/2g^{\sigma\tau})=0,
where $\det[g_{\mu\nu}]\equivg$. Requiring additionally the conformal gauge
condition $g=-1$ surprisingly implies that the waves are both transverse and
traceless. Although the ansatz for the metric is eminently reasonable when
considering perturbative gravitational waves, we show that the metric is
reducible to the metric of Minkowski space-time via a sequence of coordinate
transformations which respect the gauge conditions, without any perturbative
approximation that \in{\mu}{\nu} be small. This implies that we have, in fact,
exact plane-wave solutions; however, they are simply coordinate/conformal
artifacts. As a consequence, they carry no energy. Our result does not imply
that conformal gravity does not have gravitational wave phenomena. A different,
more generalized ansatz for the deviation, taking into account the fourth-order
nature of the field equation, which has the form
$g_{\mu\nu}=\eta_{\mu\nu}+B_{\mu\nu}(n\cdotx)G(k\cdotx)$, indeed yields waves
which carry energy and momentum [P.D. Mannheim, Gen. Relativ. Gravit. 43, 703
(2010)]. It is just surprising that transverse, traceless, plane-fronted
gravitational waves, those that would be used in any standard, perturbative,
quantum analysis of the theory, simply do not exist.
|
[
{
"created": "Fri, 12 Dec 2008 21:52:22 GMT",
"version": "v1"
},
{
"created": "Thu, 26 May 2011 20:52:42 GMT",
"version": "v2"
}
] |
2011-06-07
|
[
[
"Fabbri",
"Luca",
""
],
[
"Paranjape",
"M. B.",
""
]
] |
We consider plane-fronted, monochromatic gravitational waves on a Minkowski background, in a conformally invariant theory of general relativity. By this we mean waves of the form: $g_{\mu\nu}=\eta_{\mu\nu}+\epsilon_{\mu\nu}F(k\cdotx)$, where $\epsilon_{\mu\nu}$ is a constant polarization tensor, and $k_\mu$ is a lightlike vector. We also assume the coordinate gauge condition $|g|-1/4\partial_\tau(|g|1/4g^{\sigma\tau})=0$ which is the conformal analog of the harmonic gauge condition $g^{\mu\nu}\Gamma_{\mu\nu}^\sigma=-|g|-1/2\partial_\tau(|g|1/2g^{\sigma\tau})=0, where $\det[g_{\mu\nu}]\equivg$. Requiring additionally the conformal gauge condition $g=-1$ surprisingly implies that the waves are both transverse and traceless. Although the ansatz for the metric is eminently reasonable when considering perturbative gravitational waves, we show that the metric is reducible to the metric of Minkowski space-time via a sequence of coordinate transformations which respect the gauge conditions, without any perturbative approximation that \in{\mu}{\nu} be small. This implies that we have, in fact, exact plane-wave solutions; however, they are simply coordinate/conformal artifacts. As a consequence, they carry no energy. Our result does not imply that conformal gravity does not have gravitational wave phenomena. A different, more generalized ansatz for the deviation, taking into account the fourth-order nature of the field equation, which has the form $g_{\mu\nu}=\eta_{\mu\nu}+B_{\mu\nu}(n\cdotx)G(k\cdotx)$, indeed yields waves which carry energy and momentum [P.D. Mannheim, Gen. Relativ. Gravit. 43, 703 (2010)]. It is just surprising that transverse, traceless, plane-fronted gravitational waves, those that would be used in any standard, perturbative, quantum analysis of the theory, simply do not exist.
|
gr-qc/0407045
|
Chang Jun Gao
|
Chang Jun Gao and Shuang Nan Zhang
|
Reissner-Nordstr\"om Metric in the Friedman-Robertson-Walker Universe
|
8 pages, no figures
|
Phys.Lett. B595 (2004) 28
|
10.1016/j.physletb.2004.05.076
| null |
gr-qc astro-ph
| null |
The metric for a Reissner-Nordstr$\ddot{o}$m black hole in the background of
the Friedman-Robertson-Walker universe is obtained. Then we verified it and
discussed the influence of the evolution of the universe on the size of the
black hole. To study the problem of the orbits of a planet in the expanding
universe, we rewrote the metric in the Schwarzschild coordinates system and
deduced the equation of motion for a planet.
|
[
{
"created": "Tue, 13 Jul 2004 08:00:07 GMT",
"version": "v1"
},
{
"created": "Wed, 17 Nov 2004 07:58:14 GMT",
"version": "v2"
}
] |
2009-11-10
|
[
[
"Gao",
"Chang Jun",
""
],
[
"Zhang",
"Shuang Nan",
""
]
] |
The metric for a Reissner-Nordstr$\ddot{o}$m black hole in the background of the Friedman-Robertson-Walker universe is obtained. Then we verified it and discussed the influence of the evolution of the universe on the size of the black hole. To study the problem of the orbits of a planet in the expanding universe, we rewrote the metric in the Schwarzschild coordinates system and deduced the equation of motion for a planet.
|
1512.04113
|
Victor Shchigolev Konstantinovich
|
V. K. Shchigolev
|
Testing Fractional Action Cosmology
|
9 pages, 7 figures; minor typos corrected
|
Eur. Phys. J. Plus (2016) 131: 256
|
10.1140/epjp/i2016-16256-6
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The present work deals with a combined test of the so-called Fractional
Action Cosmology (FAC) on the example of a specific model obtained by the
author earlier. In this model, the effective cosmological term is proportional
to the Hubble parameter squared through the so-called kinematic induction. The
reason of studying this cosmological model could be explained by its ability to
describe two periods of accelerated expansion, that is in agreement with the
recent observations and the cosmological inflation paradigm. First of all, we
put our model through the theoretical tests that gives a general conception of
the influence of the model parameters on its behavior. Then, we obtain some
restrictions on the principal parameters of the model, including the fractional
index, by means of the observational data. Finally, the cosmography parameters
and the observational data compared to the theoretical predictions are
presented both analytically and graphically.
|
[
{
"created": "Sun, 13 Dec 2015 20:03:44 GMT",
"version": "v1"
},
{
"created": "Fri, 18 Dec 2015 19:19:15 GMT",
"version": "v2"
}
] |
2016-08-04
|
[
[
"Shchigolev",
"V. K.",
""
]
] |
The present work deals with a combined test of the so-called Fractional Action Cosmology (FAC) on the example of a specific model obtained by the author earlier. In this model, the effective cosmological term is proportional to the Hubble parameter squared through the so-called kinematic induction. The reason of studying this cosmological model could be explained by its ability to describe two periods of accelerated expansion, that is in agreement with the recent observations and the cosmological inflation paradigm. First of all, we put our model through the theoretical tests that gives a general conception of the influence of the model parameters on its behavior. Then, we obtain some restrictions on the principal parameters of the model, including the fractional index, by means of the observational data. Finally, the cosmography parameters and the observational data compared to the theoretical predictions are presented both analytically and graphically.
|
2404.16146
|
Rajesh Nayak K
|
Santanu Tripathy and K Rajesh Nayak
|
Static Blackhole with Cosmological Influence: Whittaker Solutions
| null | null | null | null |
gr-qc
|
http://creativecommons.org/licenses/by/4.0/
|
In this article, we investigate the impact of cosmological parameters on
black holes using an exact solution to Einstein's equations that satisfies the
Whittaker equation of state. We examine a spherically symmetric black hole in
the background of a static Einstein Universe with a perfect fluid source with
the cosmological constant. This solution is characterized by two independent
parameters, namely the size of the universe~($R$) and the cosmological
constant~(Lambda), representing the cosmological influences. We explore
phenomena such as periastron precession and the scattering of massless scalar
fields to determine how these cosmological parameters affect the physics around
black holes.
|
[
{
"created": "Wed, 24 Apr 2024 19:06:00 GMT",
"version": "v1"
}
] |
2024-04-26
|
[
[
"Tripathy",
"Santanu",
""
],
[
"Nayak",
"K Rajesh",
""
]
] |
In this article, we investigate the impact of cosmological parameters on black holes using an exact solution to Einstein's equations that satisfies the Whittaker equation of state. We examine a spherically symmetric black hole in the background of a static Einstein Universe with a perfect fluid source with the cosmological constant. This solution is characterized by two independent parameters, namely the size of the universe~($R$) and the cosmological constant~(Lambda), representing the cosmological influences. We explore phenomena such as periastron precession and the scattering of massless scalar fields to determine how these cosmological parameters affect the physics around black holes.
|
gr-qc/9711087
|
Niall O. Murchadha
|
Edward Malec (Jagiellonian University, Institute of Physics), Niall
O'Murchadha (Physics Department, University College, Cork)
|
Backscattering: an overlooked effect of General Relativity?
|
Revtex file, 4 pages
| null | null | null |
gr-qc
| null |
The total flux of outgoing radiation in a strong gravitational field
decreases due to backscattering if the sources are close to an apparent
horizon. It can cause detectable changes in the shape of signals.
Backscattering could well be of relevance to astrophysics and would constitute
a new test of the validity of general relativity. An explicit bound for this
effect is derived for scalar fields.
|
[
{
"created": "Fri, 28 Nov 1997 12:07:12 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Malec",
"Edward",
"",
"Jagiellonian University, Institute of Physics"
],
[
"O'Murchadha",
"Niall",
"",
"Physics Department, University College, Cork"
]
] |
The total flux of outgoing radiation in a strong gravitational field decreases due to backscattering if the sources are close to an apparent horizon. It can cause detectable changes in the shape of signals. Backscattering could well be of relevance to astrophysics and would constitute a new test of the validity of general relativity. An explicit bound for this effect is derived for scalar fields.
|
1711.08743
|
Soumen Roy
|
Soumen Roy, Anand S. Sengupta, Parameswaran Ajith
|
Effectual gravitational-wave template banks for coalescing compact
binaries using a hybrid placement algorithm
|
The new title: Effectual template banks for upcoming compact binary
searches in Advanced-LIGO Virgo data
|
Phys. Rev. D 99, 024048 (2019)
|
10.1103/PhysRevD.99.024048
|
LIGO Document P1700396
|
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Recent discoveries of gravitational wave (GW) signals from astrophysical
compact binary systems of neutron stars and black holes have firmly established
them as prime sources for advanced GW detectors. Theoretical templates of
expected signals from such systems have been used to filter the detector data
using the \emph{matched filtering} technique. An efficient grid over the
parameter space at a fixed minimal match has a direct impact on improving the
computational efficiency of these searches. We present the construction of
three-dimensional template banks (in component masses and an effective spin
parameter) by incorporating several new optimizations to the hybrid
geometric-random template placement algorithm that we proposed recently. These
optimizations allow us to create more efficient template banks in future
compact binary searches by shrinking the hybrid banks by $\sim 34\%$ in
comparison to the basic algorithm. Such optimized banks are also found to be
$\sim 22\%$ smaller than the optimized stochastic bank constructed over a
nominal range of parameters. We also construct an explicit hybrid template bank
with parameters identical to the `uber-bank' used in the recently-concluded CBC
searches in the second observation run of the Advanced LIGO and Virgo
detectors. We demonstrate a reduction of more than 53,000 templates over the
stochastic template bank at a near-identical coverage as determined by fitting
factor studies. A computationally efficient technique for semi-numerical
calculation of the parameter space metric, applicable for aligned-spin waveform
family, is also outlined. The resulting hybrid template banks can be generated
much faster in comparison to the stochastic banks, and are ready to be used in
the upcoming observation runs of Advanced LIGO and Virgo.
|
[
{
"created": "Thu, 23 Nov 2017 15:49:20 GMT",
"version": "v1"
},
{
"created": "Tue, 18 Dec 2018 13:06:40 GMT",
"version": "v2"
}
] |
2019-02-04
|
[
[
"Roy",
"Soumen",
""
],
[
"Sengupta",
"Anand S.",
""
],
[
"Ajith",
"Parameswaran",
""
]
] |
Recent discoveries of gravitational wave (GW) signals from astrophysical compact binary systems of neutron stars and black holes have firmly established them as prime sources for advanced GW detectors. Theoretical templates of expected signals from such systems have been used to filter the detector data using the \emph{matched filtering} technique. An efficient grid over the parameter space at a fixed minimal match has a direct impact on improving the computational efficiency of these searches. We present the construction of three-dimensional template banks (in component masses and an effective spin parameter) by incorporating several new optimizations to the hybrid geometric-random template placement algorithm that we proposed recently. These optimizations allow us to create more efficient template banks in future compact binary searches by shrinking the hybrid banks by $\sim 34\%$ in comparison to the basic algorithm. Such optimized banks are also found to be $\sim 22\%$ smaller than the optimized stochastic bank constructed over a nominal range of parameters. We also construct an explicit hybrid template bank with parameters identical to the `uber-bank' used in the recently-concluded CBC searches in the second observation run of the Advanced LIGO and Virgo detectors. We demonstrate a reduction of more than 53,000 templates over the stochastic template bank at a near-identical coverage as determined by fitting factor studies. A computationally efficient technique for semi-numerical calculation of the parameter space metric, applicable for aligned-spin waveform family, is also outlined. The resulting hybrid template banks can be generated much faster in comparison to the stochastic banks, and are ready to be used in the upcoming observation runs of Advanced LIGO and Virgo.
|
2106.09630
|
Adrian Ka-Wai Chung
|
Ka-Wai Chung, Tjonnie Guang Feng Li
|
Lensing of Gravitational Waves as a Novel Probe of Graviton Mass
|
6 pages, 4 figures; match the version published by Phys. Rev. D
| null |
10.1103/PhysRevD.104.124060
|
KCL-PH-TH 2021/41, LIGO Document number of P2100192-v2
|
gr-qc astro-ph.HE
|
http://creativecommons.org/licenses/by/4.0/
|
The diffraction patterns of lensed gravitational waves encode information
about their propagation speeds. If gravitons have mass, the dispersion relation
and speed of gravitational waves will be affected in a frequency-dependent
manner, which would leave traces in the diffraction pattern if the waves are
lensed. In this paper, we study how the alternative dispersion relation induced
by massive gravitons affects gravitational waves lensed by point-mass lenses,
such as intermediate-mass black holes. We find that the waveform morphology of
lensed dispersive gravitational waves depends on the graviton mass more
sensitively than their unlensed counterpart. Together with lensing
amplification, the waveform-morphology modifications due to lensing can improve
the measurement accuracy of the graviton mass. A single lensed
gravitational-wave signal enables us to measure the graviton mass with an
accuracy comparable with the combined measurement across $\mathcal{O}(10^3)$
unlensed signals. Our method allows us to incorporate lensed gravitational-wave
signals into existing graviton-mass measurements. Our method can also be
generalized to other lens types, gravitational-wave sources, and detector
networks, preparing ourselves for thoroughly understanding the nature of
gravitational waves in the era of lensed gravitational-wave astronomy.
|
[
{
"created": "Thu, 17 Jun 2021 16:15:08 GMT",
"version": "v1"
},
{
"created": "Mon, 15 Nov 2021 12:23:14 GMT",
"version": "v2"
},
{
"created": "Wed, 22 Dec 2021 09:42:54 GMT",
"version": "v3"
}
] |
2021-12-23
|
[
[
"Chung",
"Ka-Wai",
""
],
[
"Li",
"Tjonnie Guang Feng",
""
]
] |
The diffraction patterns of lensed gravitational waves encode information about their propagation speeds. If gravitons have mass, the dispersion relation and speed of gravitational waves will be affected in a frequency-dependent manner, which would leave traces in the diffraction pattern if the waves are lensed. In this paper, we study how the alternative dispersion relation induced by massive gravitons affects gravitational waves lensed by point-mass lenses, such as intermediate-mass black holes. We find that the waveform morphology of lensed dispersive gravitational waves depends on the graviton mass more sensitively than their unlensed counterpart. Together with lensing amplification, the waveform-morphology modifications due to lensing can improve the measurement accuracy of the graviton mass. A single lensed gravitational-wave signal enables us to measure the graviton mass with an accuracy comparable with the combined measurement across $\mathcal{O}(10^3)$ unlensed signals. Our method allows us to incorporate lensed gravitational-wave signals into existing graviton-mass measurements. Our method can also be generalized to other lens types, gravitational-wave sources, and detector networks, preparing ourselves for thoroughly understanding the nature of gravitational waves in the era of lensed gravitational-wave astronomy.
|
gr-qc/9910034
|
Sumati Surya
|
H.F.Dowker, R.S.Garcia and S.Surya
|
Morse index and causal continuity. A criterion for topology change in
quantum gravity
|
Latex, 20 pages, 3 figures
|
Class.Quant.Grav. 17 (2000) 697-712
|
10.1088/0264-9381/17/3/308
| null |
gr-qc hep-th
| null |
Studies in 1+1 dimensions suggest that causally discontinuous topology
changing spacetimes are suppressed in quantum gravity. Borde and Sorkin have
conjectured that causal discontinuities are associated precisely with index 1
or n-1 Morse points in topology changing spacetimes built from Morse functions.
We establish a weaker form of this conjecture. Namely, if a Morse function f on
a compact cobordism has critical points of index 1 or n-1, then all the Morse
geometries associated with f are causally discontinuous, while if f has no
critical points of index 1 or n-1, then there exist associated Morse geometries
which are causally continuous.
|
[
{
"created": "Mon, 11 Oct 1999 05:42:35 GMT",
"version": "v1"
}
] |
2009-10-31
|
[
[
"Dowker",
"H. F.",
""
],
[
"Garcia",
"R. S.",
""
],
[
"Surya",
"S.",
""
]
] |
Studies in 1+1 dimensions suggest that causally discontinuous topology changing spacetimes are suppressed in quantum gravity. Borde and Sorkin have conjectured that causal discontinuities are associated precisely with index 1 or n-1 Morse points in topology changing spacetimes built from Morse functions. We establish a weaker form of this conjecture. Namely, if a Morse function f on a compact cobordism has critical points of index 1 or n-1, then all the Morse geometries associated with f are causally discontinuous, while if f has no critical points of index 1 or n-1, then there exist associated Morse geometries which are causally continuous.
|
1102.5192
|
Clifford M. Will
|
Clifford M. Will
|
On the unreasonable effectiveness of the post-Newtonian approximation in
gravitational physics
|
9 pages, 2 figures, submitted to Proceedings of the National Academy
of Sciences (US)
|
Proc. Nat. Acad. Sci. (US) 108, 5938 (2011)
|
10.1073/pnas.1103127108
| null |
gr-qc astro-ph.HE hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The post-Newtonian approximation is a method for solving Einstein's field
equations for physical systems in which motions are slow compared to the speed
of light and where gravitational fields are weak. Yet it has proven to be
remarkably effective in describing certain strong-field, fast-motion systems,
including binary pulsars containing dense neutron stars and binary black hole
systems inspiraling toward a final merger. The reasons for this effectiveness
are largely unknown. When carried to high orders in the post-Newtonian
sequence, predictions for the gravitational-wave signal from inspiraling
compact binaries will play a key role in gravitational-wave detection by
laser-interferometric observatories.
|
[
{
"created": "Fri, 25 Feb 2011 08:51:15 GMT",
"version": "v1"
}
] |
2015-05-27
|
[
[
"Will",
"Clifford M.",
""
]
] |
The post-Newtonian approximation is a method for solving Einstein's field equations for physical systems in which motions are slow compared to the speed of light and where gravitational fields are weak. Yet it has proven to be remarkably effective in describing certain strong-field, fast-motion systems, including binary pulsars containing dense neutron stars and binary black hole systems inspiraling toward a final merger. The reasons for this effectiveness are largely unknown. When carried to high orders in the post-Newtonian sequence, predictions for the gravitational-wave signal from inspiraling compact binaries will play a key role in gravitational-wave detection by laser-interferometric observatories.
|
2101.00266
|
Valerio Faraoni
|
Valerio Faraoni (Bishop's U.), Andrea Giusti (ETH Zurich), and Bardia
H. Fahim (Bishop's U.)
|
Spherical inhomogeneous solutions of Einstein and scalar-tensor gravity:
a map of the land
|
140 pages, one figure. Explanation text and bibliography expanded,
typographical errors corrected. Matches version to appear in Physics Reports
| null |
10.1016/j.physrep.2021.04.003
| null |
gr-qc astro-ph.HE
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We review spherical and inhomogeneous analytic solutions of the field
equations of Einstein and of scalar-tensor gravity, including Brans-Dicke
theory, non-minimally (possibly conformally) coupled scalar fields, Horndeski,
and beyond Horndeski/DHOST gravity. The zoo includes both static and dynamic
solutions, asymptotically flat, and asymptotically
Friedmann-Lema\^itre-Robertson-Walker ones. We minimize overlap with existing
books and reviews and we place emphasis on scalar field spacetimes and on
geometries that are "general" within certain classes. Relations between various
solutions, which have largely emerged during the last decade, are pointed out.
|
[
{
"created": "Fri, 1 Jan 2021 16:35:39 GMT",
"version": "v1"
},
{
"created": "Tue, 27 Apr 2021 12:43:26 GMT",
"version": "v2"
}
] |
2021-07-28
|
[
[
"Faraoni",
"Valerio",
"",
"Bishop's U."
],
[
"Giusti",
"Andrea",
"",
"ETH Zurich"
],
[
"Fahim",
"Bardia H.",
"",
"Bishop's U."
]
] |
We review spherical and inhomogeneous analytic solutions of the field equations of Einstein and of scalar-tensor gravity, including Brans-Dicke theory, non-minimally (possibly conformally) coupled scalar fields, Horndeski, and beyond Horndeski/DHOST gravity. The zoo includes both static and dynamic solutions, asymptotically flat, and asymptotically Friedmann-Lema\^itre-Robertson-Walker ones. We minimize overlap with existing books and reviews and we place emphasis on scalar field spacetimes and on geometries that are "general" within certain classes. Relations between various solutions, which have largely emerged during the last decade, are pointed out.
|
1911.12521
|
Mahamat Saleh
|
Ragil Tsafack Ndongmo, Saleh Mahamat, Thomas Bouetou Bouetou and
Timoleon Crepin Kofane
|
Thermodynamic of a rotating and Non-linear magnetic-charged black hole
in the quintessence field
|
8 pages, 12 figures
| null | null | null |
gr-qc
|
http://creativecommons.org/publicdomain/zero/1.0/
|
We purpose an approach for the thermodynamic analysis of rotating and
non-linear magnetic-charged black hole with quintessence. Accordingly, we
compute various thermodynamics quantities of the black hole, such as mass,
temperature, potential provided from the magnetic charge, and the heat
capacity. Moreover, we study phase transitions of this black hole, analyzing
the plot of its heat capacity. Then, we have shown that the black hole mass
would have a phase of decrease, while the temperature increases from negative
absolute temperatures. From the behavior of the heat capacity, we point out
that the black hole undergoes to a second-order phase transition, which is
shifted towards the higher values of entropy as we increase the rotating
parameter $a$ or the magnetic parameter $Q$.
|
[
{
"created": "Thu, 28 Nov 2019 04:28:39 GMT",
"version": "v1"
}
] |
2019-12-02
|
[
[
"Ndongmo",
"Ragil Tsafack",
""
],
[
"Mahamat",
"Saleh",
""
],
[
"Bouetou",
"Thomas Bouetou",
""
],
[
"Kofane",
"Timoleon Crepin",
""
]
] |
We purpose an approach for the thermodynamic analysis of rotating and non-linear magnetic-charged black hole with quintessence. Accordingly, we compute various thermodynamics quantities of the black hole, such as mass, temperature, potential provided from the magnetic charge, and the heat capacity. Moreover, we study phase transitions of this black hole, analyzing the plot of its heat capacity. Then, we have shown that the black hole mass would have a phase of decrease, while the temperature increases from negative absolute temperatures. From the behavior of the heat capacity, we point out that the black hole undergoes to a second-order phase transition, which is shifted towards the higher values of entropy as we increase the rotating parameter $a$ or the magnetic parameter $Q$.
|
1111.4661
|
Julien Ribassin
|
J. Ribassin, E. Huguet and K. Ganga
|
Simple fluid models for super-inflation in effective LQC and effects on
the CMB B-modes
|
8 pages, 15 figures
| null | null | null |
gr-qc astro-ph.CO hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Loop quantum cosmology allows to replace the original singularity by a
quantum bounce followed by a phase of fast expansion called super-inflation. In
this paper, we use a simple analytic description of super-inflation using the
equation of state of a fluid. We then derive the power spectrum of tensor
perturbations produced. The effects on the B-mode polarization of the
cosmological background radiation are discussed. For a large region of phase
space, the spectrum should be distinguishable from the standard inflationary
prediction for future observations.
|
[
{
"created": "Sun, 20 Nov 2011 18:36:34 GMT",
"version": "v1"
}
] |
2015-03-19
|
[
[
"Ribassin",
"J.",
""
],
[
"Huguet",
"E.",
""
],
[
"Ganga",
"K.",
""
]
] |
Loop quantum cosmology allows to replace the original singularity by a quantum bounce followed by a phase of fast expansion called super-inflation. In this paper, we use a simple analytic description of super-inflation using the equation of state of a fluid. We then derive the power spectrum of tensor perturbations produced. The effects on the B-mode polarization of the cosmological background radiation are discussed. For a large region of phase space, the spectrum should be distinguishable from the standard inflationary prediction for future observations.
|
1505.04568
|
Peng Wang
|
Peng Wang, Haitang Yang and Shuxuan Ying
|
Black Hole Radiation with Modified Dispersion Relation in Tunneling
Paradigm: Free-fall Frame
|
28 pages. arXiv admin note: substantial text overlap with
arXiv:1505.03045
| null |
10.1140/epjc/s10052-015-3858-y
|
CTP-SCU/2015009
|
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Due to the exponential high gravitational red shift near the event horizon of
a black hole, it might appear that the Hawking radiation would be highly
sensitive to some unknown high energy physics. To study effects of any unknown
physics at the Planck scale on the Hawking radiation, the dispersive field
theory models have been proposed, which are variations of Unruh's sonic black
hole analogy. In this paper, we use the Hamilton-Jacobi method to investigate
the dispersive field theory models. The preferred frame is the free-fall frame
of the black hole. The dispersion relation adopted agrees with the relativistic
one at low energy but is modified near the Planck mass $m_{p}$. The corrections
to the Hawking temperature are calculated for massive and charged particles to
$\mathcal{O}\left( m_{p}^{-2}\right) $ and neutral and massless particles with
$\lambda=0$ to all orders. The Hawking temperature of radiation agrees with the
standard one at the leading order. After the spectrum of radiation near the
horizon is obtained, we use the brick wall model to compute the thermal entropy
of a massless scalar field near the horizon of a 4D spherically symmetric black
hole and a 2D one. Finally, the luminosity of a Schwarzschild black hole is
calculated by using the geometric optics approximation.
|
[
{
"created": "Mon, 18 May 2015 09:30:59 GMT",
"version": "v1"
}
] |
2016-02-17
|
[
[
"Wang",
"Peng",
""
],
[
"Yang",
"Haitang",
""
],
[
"Ying",
"Shuxuan",
""
]
] |
Due to the exponential high gravitational red shift near the event horizon of a black hole, it might appear that the Hawking radiation would be highly sensitive to some unknown high energy physics. To study effects of any unknown physics at the Planck scale on the Hawking radiation, the dispersive field theory models have been proposed, which are variations of Unruh's sonic black hole analogy. In this paper, we use the Hamilton-Jacobi method to investigate the dispersive field theory models. The preferred frame is the free-fall frame of the black hole. The dispersion relation adopted agrees with the relativistic one at low energy but is modified near the Planck mass $m_{p}$. The corrections to the Hawking temperature are calculated for massive and charged particles to $\mathcal{O}\left( m_{p}^{-2}\right) $ and neutral and massless particles with $\lambda=0$ to all orders. The Hawking temperature of radiation agrees with the standard one at the leading order. After the spectrum of radiation near the horizon is obtained, we use the brick wall model to compute the thermal entropy of a massless scalar field near the horizon of a 4D spherically symmetric black hole and a 2D one. Finally, the luminosity of a Schwarzschild black hole is calculated by using the geometric optics approximation.
|
1312.3759
|
Masato Minamitsuji
|
Masato Minamitsuji
|
Solutions in the scalar-tensor theory with nonminimal derivative
coupling
|
Phys.Rev.D 89, 064017 (2014)
| null |
10.1103/PhysRevD.89.064017
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We present black hole type solutions in the scalar-tensor theory with
nonminimal derivative coupling to the Einstein tensor. The effects of the
nonminimal derivative coupling appear in the large scales, while the solutions
approach those in the Einstein gravity in the small scales. For the particular
coupling constant tuned to the inverse of the cosmological constant, the scalar
field becomes trivial and the solutions in the Einstein gravity are recovered.
For the other coupling constant, more general solutions can be obtained. If the
two-dimensional maximally symmetric space is a two-sphere, the spacetime
structure approaches anti-de Sitter spacetime in the large scales. On the other
hand, if the two-dimensional space is a two-hyperboloid, the spacetime
approaches de Sitter (AdS) spacetime. If it is a flat space, the cosmological
constant affects only the amplitude of the scalar field. The extension to the
higher-dimensional case is also straightforward. For a certain range of the
negative cosmological constant, thermodynamic properties of a black hole are
very similar to those of the Schwarzschild-AdS black hole in the Einstein
gravity.
|
[
{
"created": "Fri, 13 Dec 2013 10:29:09 GMT",
"version": "v1"
},
{
"created": "Tue, 3 Jun 2014 05:41:48 GMT",
"version": "v2"
}
] |
2015-06-18
|
[
[
"Minamitsuji",
"Masato",
""
]
] |
We present black hole type solutions in the scalar-tensor theory with nonminimal derivative coupling to the Einstein tensor. The effects of the nonminimal derivative coupling appear in the large scales, while the solutions approach those in the Einstein gravity in the small scales. For the particular coupling constant tuned to the inverse of the cosmological constant, the scalar field becomes trivial and the solutions in the Einstein gravity are recovered. For the other coupling constant, more general solutions can be obtained. If the two-dimensional maximally symmetric space is a two-sphere, the spacetime structure approaches anti-de Sitter spacetime in the large scales. On the other hand, if the two-dimensional space is a two-hyperboloid, the spacetime approaches de Sitter (AdS) spacetime. If it is a flat space, the cosmological constant affects only the amplitude of the scalar field. The extension to the higher-dimensional case is also straightforward. For a certain range of the negative cosmological constant, thermodynamic properties of a black hole are very similar to those of the Schwarzschild-AdS black hole in the Einstein gravity.
|
0802.0459
|
Janna Levin
|
Janna Levin and Gabe Perez-Giz
|
A Periodic Table for Black Hole Orbits
|
42 pages, lots of figures
| null |
10.1103/PhysRevD.77.103005
| null |
gr-qc astro-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Understanding the dynamics around rotating black holes is imperative to the
success of the future gravitational wave observatories. Although integrable in
principle, test particle orbits in the Kerr spacetime can also be elaborate,
and while they have been studied extensively, classifying their general
properties has been a challenge. This is the first in a series of papers that
adopts a dynamical systems approach to the study of Kerr orbits, beginning with
equatorial orbits. We define a taxonomy of orbits that hinges on a
correspondence between periodic orbits and rational numbers. The taxonomy
defines the entire dynamics, including aperiodic motion, since every orbit is
in or near the periodic set. A remarkable implication of this periodic orbit
taxonomy is that the simple precessing ellipse familiar from planetary orbits
is not allowed in the strong-field regime. Instead, eccentric orbits trace out
precessions of multi-leaf clovers in the final stages of inspiral. Furthermore,
for any black hole, there is some point in the strong-field regime past which
zoom-whirl behavior becomes unavoidable. Finally, we sketch the potential
application of the taxonomy to problems of astrophysical interest, in
particular its utility for computationally intensive gravitational wave
calculations.
|
[
{
"created": "Mon, 4 Feb 2008 17:22:43 GMT",
"version": "v1"
}
] |
2009-11-13
|
[
[
"Levin",
"Janna",
""
],
[
"Perez-Giz",
"Gabe",
""
]
] |
Understanding the dynamics around rotating black holes is imperative to the success of the future gravitational wave observatories. Although integrable in principle, test particle orbits in the Kerr spacetime can also be elaborate, and while they have been studied extensively, classifying their general properties has been a challenge. This is the first in a series of papers that adopts a dynamical systems approach to the study of Kerr orbits, beginning with equatorial orbits. We define a taxonomy of orbits that hinges on a correspondence between periodic orbits and rational numbers. The taxonomy defines the entire dynamics, including aperiodic motion, since every orbit is in or near the periodic set. A remarkable implication of this periodic orbit taxonomy is that the simple precessing ellipse familiar from planetary orbits is not allowed in the strong-field regime. Instead, eccentric orbits trace out precessions of multi-leaf clovers in the final stages of inspiral. Furthermore, for any black hole, there is some point in the strong-field regime past which zoom-whirl behavior becomes unavoidable. Finally, we sketch the potential application of the taxonomy to problems of astrophysical interest, in particular its utility for computationally intensive gravitational wave calculations.
|
2003.12179
|
Matthew Fox
|
Matthew S. Fox
|
Electric Multipole Fields of Higher-Dimensional Massive Bodies
|
11 pages; updated references; accepted to PRD
|
Phys. Rev. D 102, 044008 (2020)
|
10.1103/PhysRevD.102.044008
| null |
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
It was shown in a recent paper [J. Math. Phys. 60, 102502 (2019)] that slowly
lowering an electric charge into a Schwarzschild-Tangherlini (ST) black hole
endows the final state with electric multipole fields, which implies the final
state geometry is not Reissner-Nordstr\"om-Tangherlini in nature. This
conclusion departs from the four-dimensional case in which the no-hair theorem
(NHT) requires the final state to be a Reissner-Nordstr\"om black hole. To
better understand this discrepancy clearly requires a deeper understanding of
the origin of the multipole hair in the higher-dimensional case. In this paper,
we advance the conjecture that charged, static, and asymptotically-flat
higher-dimensional black holes can acquire electric multipole hair only after
they form. This supposition derives from studying the asymptotic behavior of
the field of a multipole charge onto which a massive and hyperspherical shell
with an exterior ST geometry is collapsing. In the mathematical limit as the
shell approaches its ST radius, we find that the multipole fields (except the
monopole) vanish. This implies that the only information of an arbitrary (but
finite) charge distribution inside the collapsing shell that is available to an
asymptotic observer is the total electric charge. Our results yield
considerable insight into how higher-dimensional black holes acquire electric
multipole hair, and also imply that, in four dimensions, the fadeaway of
multipole moments during gravitational collapse is not strictly because of the
NHT.
|
[
{
"created": "Thu, 26 Mar 2020 22:42:20 GMT",
"version": "v1"
},
{
"created": "Tue, 28 Jul 2020 03:53:29 GMT",
"version": "v2"
}
] |
2020-08-06
|
[
[
"Fox",
"Matthew S.",
""
]
] |
It was shown in a recent paper [J. Math. Phys. 60, 102502 (2019)] that slowly lowering an electric charge into a Schwarzschild-Tangherlini (ST) black hole endows the final state with electric multipole fields, which implies the final state geometry is not Reissner-Nordstr\"om-Tangherlini in nature. This conclusion departs from the four-dimensional case in which the no-hair theorem (NHT) requires the final state to be a Reissner-Nordstr\"om black hole. To better understand this discrepancy clearly requires a deeper understanding of the origin of the multipole hair in the higher-dimensional case. In this paper, we advance the conjecture that charged, static, and asymptotically-flat higher-dimensional black holes can acquire electric multipole hair only after they form. This supposition derives from studying the asymptotic behavior of the field of a multipole charge onto which a massive and hyperspherical shell with an exterior ST geometry is collapsing. In the mathematical limit as the shell approaches its ST radius, we find that the multipole fields (except the monopole) vanish. This implies that the only information of an arbitrary (but finite) charge distribution inside the collapsing shell that is available to an asymptotic observer is the total electric charge. Our results yield considerable insight into how higher-dimensional black holes acquire electric multipole hair, and also imply that, in four dimensions, the fadeaway of multipole moments during gravitational collapse is not strictly because of the NHT.
|
1108.4012
|
Alexandre Baranov
|
Alexandre M.Baranov
|
The Demonstration of Gravitational Phase Transition inside of Fluid
Static Ball
|
7 pages, 1 figure, Journal of Siberian Federal University.
Mathematics & Physics
|
J.Sib.Fed.U.4(3):275-281,2011
| null | null |
gr-qc hep-th math-ph math.MP
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
It is shown that at the center of gravitating fluid ball there is the phase
transition of second kind of gravitational field as a change of field's
algebraic type.
|
[
{
"created": "Fri, 19 Aug 2011 17:20:35 GMT",
"version": "v1"
}
] |
2011-08-22
|
[
[
"Baranov",
"Alexandre M.",
""
]
] |
It is shown that at the center of gravitating fluid ball there is the phase transition of second kind of gravitational field as a change of field's algebraic type.
|
gr-qc/9807031
|
Frank Wilczek
|
Maulik K. Parikh and Frank Wilczek
|
Global Structure of Evaporating Black Holes
|
LaTeX, 10 pages, 1 figure; v2: references added, uncorrupted figure
file
|
Phys.Lett. B449 (1999) 24-29
|
10.1016/S0370-2693(99)00071-4
|
PUPT-1801 and IASSNS-HEP-98-57
|
gr-qc hep-th
| null |
By extending the charged Vaidya metric to cover all of spacetime, we obtain a
Penrose diagram for the formation and evaporation of a charged black hole. In
this construction, the singularity is time-like. The entire spacetime can be
predicted from initial conditions if boundary conditions at the singularity are
known.
|
[
{
"created": "Tue, 14 Jul 1998 20:41:51 GMT",
"version": "v1"
},
{
"created": "Fri, 4 Feb 2000 17:29:24 GMT",
"version": "v2"
}
] |
2009-10-31
|
[
[
"Parikh",
"Maulik K.",
""
],
[
"Wilczek",
"Frank",
""
]
] |
By extending the charged Vaidya metric to cover all of spacetime, we obtain a Penrose diagram for the formation and evaporation of a charged black hole. In this construction, the singularity is time-like. The entire spacetime can be predicted from initial conditions if boundary conditions at the singularity are known.
|
gr-qc/9508042
| null |
Walter Simon
|
Nuts have no hair
|
8 pages, Latex file, no figures
|
Class.Quant.Grav.12:L125-L130,1995
|
10.1088/0264-9381/12/12/004
| null |
gr-qc
| null |
We show that the Riemannian Kerr solutions are the only Riemannian,
Ricci-flat and asymptotically flat ${\rm C}^{2}$-metrics $g_{\mu\nu}$ on a
4-dimensional complete manifold ${\cal M}$ of topology ${\rm R}^{2} \times {\rm
S}^{2}$ which have (at least) a 1-parameter group of periodic isometries with
only isolated fixed points ("nuts") and with orbits of bounded length at
infinity.
|
[
{
"created": "Fri, 18 Aug 1995 18:32:00 GMT",
"version": "v1"
}
] |
2010-04-06
|
[
[
"Simon",
"Walter",
""
]
] |
We show that the Riemannian Kerr solutions are the only Riemannian, Ricci-flat and asymptotically flat ${\rm C}^{2}$-metrics $g_{\mu\nu}$ on a 4-dimensional complete manifold ${\cal M}$ of topology ${\rm R}^{2} \times {\rm S}^{2}$ which have (at least) a 1-parameter group of periodic isometries with only isolated fixed points ("nuts") and with orbits of bounded length at infinity.
|
2207.01464
|
Wen-Biao Han
|
Cheng Zhang, Wen-Biao Han, Shu-Cheng Yang
|
Gravitational-wave bursts from spin-precessing black holes in binary
systems
|
5 pages, 2 figures
|
MNRAS 516, L107, 2022
|
10.1093/mnrasl/slac100
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Gravitational waves from precessing binary black holes exhibit new features
that are absent in non-precessionary systems. All current waveform models take
into account only the modulation of the signal due to precession. In this
letter, we find that this effect has its own signature, by gravitational
emission of a short and transient signal, or burst. The frequency of the burst
is comparable to that of the late stage of the inspiral. We show that under
certain conditions, this signal is strong enough to be detected by Advanced
LIGO. For third-generation detectors like the Einstein telescope, the
calculated signal-to-noise ratio can reach higher values. Measurements of
precession would provide valuable insights into the intrinsic structure of
black holes, and therefore into astrophysical binary formation mechanisms.
|
[
{
"created": "Mon, 4 Jul 2022 14:50:56 GMT",
"version": "v1"
},
{
"created": "Mon, 28 Nov 2022 07:16:29 GMT",
"version": "v2"
},
{
"created": "Wed, 21 Dec 2022 09:00:58 GMT",
"version": "v3"
}
] |
2022-12-22
|
[
[
"Zhang",
"Cheng",
""
],
[
"Han",
"Wen-Biao",
""
],
[
"Yang",
"Shu-Cheng",
""
]
] |
Gravitational waves from precessing binary black holes exhibit new features that are absent in non-precessionary systems. All current waveform models take into account only the modulation of the signal due to precession. In this letter, we find that this effect has its own signature, by gravitational emission of a short and transient signal, or burst. The frequency of the burst is comparable to that of the late stage of the inspiral. We show that under certain conditions, this signal is strong enough to be detected by Advanced LIGO. For third-generation detectors like the Einstein telescope, the calculated signal-to-noise ratio can reach higher values. Measurements of precession would provide valuable insights into the intrinsic structure of black holes, and therefore into astrophysical binary formation mechanisms.
|
1012.1738
|
Wolfgang Wieland
|
Wolfgang Wieland
|
Complex Ashtekar variables and reality conditions for Holst's action
|
24 pages, 2 pictures
|
Annales H. Poincar\'e (2011), 1-24
|
10.1007/s00023-011-0134-z
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
From the Holst action in terms of complex valued Ashtekar variables
additional reality conditions mimicking the linear simplicity constraints of
spin foam gravity are found. In quantum theory with the results of You and
Rovelli we are able to implement these constraints weakly, that is in the sense
of Gupta and Bleuler. The resulting kinematical Hilbert space matches the
original one of loop quantum gravity, that is for real valued Ashtekar
connection. Our result perfectly fit with recent developments of Rovelli and
Speziale concerning Lorentz covariance within spin-form gravity.
|
[
{
"created": "Wed, 8 Dec 2010 11:17:43 GMT",
"version": "v1"
},
{
"created": "Tue, 24 Jan 2012 11:30:05 GMT",
"version": "v2"
}
] |
2012-01-25
|
[
[
"Wieland",
"Wolfgang",
""
]
] |
From the Holst action in terms of complex valued Ashtekar variables additional reality conditions mimicking the linear simplicity constraints of spin foam gravity are found. In quantum theory with the results of You and Rovelli we are able to implement these constraints weakly, that is in the sense of Gupta and Bleuler. The resulting kinematical Hilbert space matches the original one of loop quantum gravity, that is for real valued Ashtekar connection. Our result perfectly fit with recent developments of Rovelli and Speziale concerning Lorentz covariance within spin-form gravity.
|
gr-qc/0302024
|
Allan Widom
|
Y.N. Srivastava, A. Widom, G. Pizzella
|
Electronic Enhancements in the Detection of Gravitational Waves by
Metallic Antennae
|
15 pages, one figure
| null | null | null |
gr-qc
| null |
For mechanical Weber gravitational wave antennae, it is thought that gravity
waves are weakly converted into acoustic vibrations. Acoustic vibrations in
metals (such as Aluminum) are experimentally known to be attenuated by the
creation of electron-hole pairs described via the electronic viscosity. These
final state electronic excitations give rise to gravitational wave absorption
cross sections which are considerably larger (by four orders of magnitude) than
those in previous theories which have not explicitly considered electronic
excitations.
|
[
{
"created": "Fri, 7 Feb 2003 18:02:51 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Srivastava",
"Y. N.",
""
],
[
"Widom",
"A.",
""
],
[
"Pizzella",
"G.",
""
]
] |
For mechanical Weber gravitational wave antennae, it is thought that gravity waves are weakly converted into acoustic vibrations. Acoustic vibrations in metals (such as Aluminum) are experimentally known to be attenuated by the creation of electron-hole pairs described via the electronic viscosity. These final state electronic excitations give rise to gravitational wave absorption cross sections which are considerably larger (by four orders of magnitude) than those in previous theories which have not explicitly considered electronic excitations.
|
1305.2932
|
Joshua Cooperman
|
Joshua H. Cooperman, Jonah Miller
|
A first look at transition amplitudes in (2+1)-dimensional causal
dynamical triangulations
|
27 pages, 14 figures, 1 table; reflects published version
|
Classical and Quantum Gravity 31 (2014) 035012
|
10.1088/0264-9381/31/3/035012
| null |
gr-qc hep-lat hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We study a lattice regularization of the gravitational path integral--causal
dynamical triangulations--for (2+1)-dimensional Einstein gravity with positive
cosmological constant in the presence of past and future spacelike boundaries
of fixed intrinsic geometries. For spatial topology of a 2-sphere, we determine
the form of the Einstein-Hilbert action supplemented by the
Gibbons-Hawking-York boundary terms within the Regge calculus of causal
triangulations. Employing this action we numerically simulate a variety of
transition amplitudes from the past boundary to the future boundary. To the
extent that we have so far investigated them, these transition amplitudes
appear consistent with the gravitational effective action previously found to
characterize the ground state of quantum spacetime geometry within the
Euclidean de Sitter-like phase. Certain of these transition amplitudes
convincingly demonstrate that the so-called stalks present in this phase are
numerical artifacts of the lattice regularization, seemingly indicate that the
quantization technique of causal dynamical triangulations differs in detail
from that of the no-boundary proposal of Hartle and Hawking, and possibly
represent the first numerical simulations of portions of temporally unbounded
quantum spacetime geometry within the causal dynamical triangulations approach.
We also uncover tantalizing evidence suggesting that Lorentzian not Euclidean
de Sitter spacetime dominates the ground state on sufficiently large scales.
|
[
{
"created": "Mon, 13 May 2013 20:01:04 GMT",
"version": "v1"
},
{
"created": "Mon, 10 Jun 2013 05:14:06 GMT",
"version": "v2"
},
{
"created": "Wed, 15 Jan 2014 10:35:20 GMT",
"version": "v3"
}
] |
2014-01-16
|
[
[
"Cooperman",
"Joshua H.",
""
],
[
"Miller",
"Jonah",
""
]
] |
We study a lattice regularization of the gravitational path integral--causal dynamical triangulations--for (2+1)-dimensional Einstein gravity with positive cosmological constant in the presence of past and future spacelike boundaries of fixed intrinsic geometries. For spatial topology of a 2-sphere, we determine the form of the Einstein-Hilbert action supplemented by the Gibbons-Hawking-York boundary terms within the Regge calculus of causal triangulations. Employing this action we numerically simulate a variety of transition amplitudes from the past boundary to the future boundary. To the extent that we have so far investigated them, these transition amplitudes appear consistent with the gravitational effective action previously found to characterize the ground state of quantum spacetime geometry within the Euclidean de Sitter-like phase. Certain of these transition amplitudes convincingly demonstrate that the so-called stalks present in this phase are numerical artifacts of the lattice regularization, seemingly indicate that the quantization technique of causal dynamical triangulations differs in detail from that of the no-boundary proposal of Hartle and Hawking, and possibly represent the first numerical simulations of portions of temporally unbounded quantum spacetime geometry within the causal dynamical triangulations approach. We also uncover tantalizing evidence suggesting that Lorentzian not Euclidean de Sitter spacetime dominates the ground state on sufficiently large scales.
|
1204.2122
|
Bindu Anubha Bambah
|
Bindu A. Bambah, C. Mukku, T. Shreecharan and K. Siva Prasad
|
Entanglement in a model for Hawking radiation: An Application of
Quadratic Algebras
|
20 pages, 15 figures. revised version with one figure removed
| null |
10.1016/j.aop.2012.11.015
| null |
gr-qc math-ph math.MP quant-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Quadratic polynomially deformed $su(1,1)$ and $su(2)$ algebras are utilised
in model Hamiltonians to show how the gravitational system consisting of a
black hole, infalling radiation and outgoing (Hawking) radiation can be solved
exactly. The models allow us to study the long-time behaviour of the black hole
and its outgoing modes. In particular, we calculate the bipartite entanglement
entropies of subsystems consisting of a) infalling plus outgoing modes and b)
black hole modes plus the infalling modes,using the Janus-faced nature of the
model.The long-time behaviour also gives us glimpses of modifications in the
character of Hawking radiation. Lastly, we study the phenomenon of
superradiance in our model in analogy with atomic Dicke superradiance.
|
[
{
"created": "Tue, 10 Apr 2012 12:30:43 GMT",
"version": "v1"
},
{
"created": "Wed, 25 Apr 2012 04:56:26 GMT",
"version": "v2"
}
] |
2015-06-04
|
[
[
"Bambah",
"Bindu A.",
""
],
[
"Mukku",
"C.",
""
],
[
"Shreecharan",
"T.",
""
],
[
"Prasad",
"K. Siva",
""
]
] |
Quadratic polynomially deformed $su(1,1)$ and $su(2)$ algebras are utilised in model Hamiltonians to show how the gravitational system consisting of a black hole, infalling radiation and outgoing (Hawking) radiation can be solved exactly. The models allow us to study the long-time behaviour of the black hole and its outgoing modes. In particular, we calculate the bipartite entanglement entropies of subsystems consisting of a) infalling plus outgoing modes and b) black hole modes plus the infalling modes,using the Janus-faced nature of the model.The long-time behaviour also gives us glimpses of modifications in the character of Hawking radiation. Lastly, we study the phenomenon of superradiance in our model in analogy with atomic Dicke superradiance.
|
0803.0268
|
Nobuyuki Sakai
|
Eduardo I. Guendelman (Ben Gurion U), Nobuyuki Sakai (Yamagata U)
|
The universe out of a breathing bubble
|
12 pages, 5 figures, discussions and 2 figures added, to appear in
PRD
|
Phys.Rev.D77:125002,2008; Erratum-ibid.D80:049901,2009
|
10.1103/PhysRevD.77.125002 10.1103/PhysRevD.80.049901
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We consider the model of a false vacuum bubble with a thin wall where the
surface energy density is composed of two different components, "domain-wall"
type and "dust" type, with opposite signs. We find stably oscillating
solutions, which we call "breathing bubbles". By decay to a lower mass state,
such a breathing bubble could become either i) a child universe or ii) a bubble
that "eats up" the original universe, depending on the sign of the surface
energy of the "domain-wall" component. We also discuss the effect of the
finite-thickness corrections to the thin-wall approximation and possible
origins of the energy contents of our model.
|
[
{
"created": "Mon, 3 Mar 2008 15:53:00 GMT",
"version": "v1"
},
{
"created": "Mon, 14 Apr 2008 15:06:58 GMT",
"version": "v2"
}
] |
2014-11-18
|
[
[
"Guendelman",
"Eduardo I.",
"",
"Ben Gurion U"
],
[
"Sakai",
"Nobuyuki",
"",
"Yamagata U"
]
] |
We consider the model of a false vacuum bubble with a thin wall where the surface energy density is composed of two different components, "domain-wall" type and "dust" type, with opposite signs. We find stably oscillating solutions, which we call "breathing bubbles". By decay to a lower mass state, such a breathing bubble could become either i) a child universe or ii) a bubble that "eats up" the original universe, depending on the sign of the surface energy of the "domain-wall" component. We also discuss the effect of the finite-thickness corrections to the thin-wall approximation and possible origins of the energy contents of our model.
|
gr-qc/0612141
|
M Iftime
|
M.D. Iftime
|
Gauge and General Relativity
|
12 pages, submitted
| null | null | null |
gr-qc
| null |
One of the main features of covariant theories, in particular general
relativity, is that the field equation possesses gauge freedom associated with
global diffeomorphisms of the underlying manifold. I shall explain here how the
hole argument is a reflection of this gauge freedom.
Finally I shall point out some implications of the hole argument and extend
the hole argument to the case of permutable theories. As covariant theories
provides a general mathematical framework for classical physics, permutable
theories provide the language for quantum physics. Permutable theories are
defined functorially on the category of sets and permutations with values into
the category of fibered sets and fiber-preserving automorphisms, and rules of
selecting sections. The hole argument for permutable theories is intimately
related with the individuation problem of the base elements (e.g., elementary
particles). This is a consequence of the fact that the automorphisms of the
base space provides the gauge freedom of the fields.
|
[
{
"created": "Fri, 22 Dec 2006 02:47:47 GMT",
"version": "v1"
},
{
"created": "Thu, 1 Mar 2007 16:49:51 GMT",
"version": "v2"
},
{
"created": "Tue, 29 Jan 2008 20:49:38 GMT",
"version": "v3"
}
] |
2008-01-29
|
[
[
"Iftime",
"M. D.",
""
]
] |
One of the main features of covariant theories, in particular general relativity, is that the field equation possesses gauge freedom associated with global diffeomorphisms of the underlying manifold. I shall explain here how the hole argument is a reflection of this gauge freedom. Finally I shall point out some implications of the hole argument and extend the hole argument to the case of permutable theories. As covariant theories provides a general mathematical framework for classical physics, permutable theories provide the language for quantum physics. Permutable theories are defined functorially on the category of sets and permutations with values into the category of fibered sets and fiber-preserving automorphisms, and rules of selecting sections. The hole argument for permutable theories is intimately related with the individuation problem of the base elements (e.g., elementary particles). This is a consequence of the fact that the automorphisms of the base space provides the gauge freedom of the fields.
|
1502.07105
|
Branislav Cvetkovi\"A
|
M. Blagojevi\'c and B. Cvetkovi\'c
|
Vaidya-like exact solutions with torsion
|
LaTeX, 15 pages, 2 figures; v2 minor revisions
|
JHEP05(2015)101
|
10.1007/JHEP05(2015)101
| null |
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Starting from the Oliva--Tempo--Troncoso black hole, a solution of the
Bergshoeff--Hohm--Townsend massive gravity, a class of the Vaidya-like exact
vacuum solutions with torsion is constructed in the three-dimensional
Poincar\'e gauge theory. A particular subclass of these solutions is shown to
possess the asymptotic conformal symmetry. The related canonical energy
contains a contribution stemming from torsion.
|
[
{
"created": "Wed, 25 Feb 2015 10:11:18 GMT",
"version": "v1"
},
{
"created": "Thu, 16 Apr 2015 16:11:32 GMT",
"version": "v2"
}
] |
2016-08-08
|
[
[
"Blagojević",
"M.",
""
],
[
"Cvetković",
"B.",
""
]
] |
Starting from the Oliva--Tempo--Troncoso black hole, a solution of the Bergshoeff--Hohm--Townsend massive gravity, a class of the Vaidya-like exact vacuum solutions with torsion is constructed in the three-dimensional Poincar\'e gauge theory. A particular subclass of these solutions is shown to possess the asymptotic conformal symmetry. The related canonical energy contains a contribution stemming from torsion.
|
1910.12262
|
Che-Yu Chen
|
Che-Yu Chen, Pisin Chen
|
Eikonal black hole ringings in generalized energy-momentum squared
gravity
|
11 pages. Updated to match the published version
|
Phys. Rev. D 101, 064021 (2020)
|
10.1103/PhysRevD.101.064021
| null |
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
In the scope of black hole spectroscopy, several attempts have been made in
the past decades in order to test black holes or gravitational theories via
black hole quasinormal modes. In the eikonal approximation, the quasinormal
modes are generically associated with the photon ring of the black hole. This
correspondence is valid for most cases in general relativity, but may not be
true in other theories of gravity. In this paper, we consider the generalized
energy-momentum squared gravity in which matter fields are non-minimally
coupled to geometry. We investigate the axial perturbations of the charged
black holes in this model, without assuming any explicit expression of the
action functional. After obtaining the modified Klein-Gordon equation and the
modified Maxwell equations, we perturb the gravitational equations and the
modified Maxwell equations to derive the coupled master equations of the axial
perturbations. In the presence of the non-minimal coupling between matter and
geometry, the correspondence between the eikonal quasinormal modes and the
photon ring is not satisfied in general. Also, the two coupled fields of the
axial perturbations are found to propagate independently and they do not share
the same quasinormal frequencies in the eikonal limit.
|
[
{
"created": "Sun, 27 Oct 2019 13:31:05 GMT",
"version": "v1"
},
{
"created": "Wed, 11 Mar 2020 15:05:13 GMT",
"version": "v2"
}
] |
2020-03-12
|
[
[
"Chen",
"Che-Yu",
""
],
[
"Chen",
"Pisin",
""
]
] |
In the scope of black hole spectroscopy, several attempts have been made in the past decades in order to test black holes or gravitational theories via black hole quasinormal modes. In the eikonal approximation, the quasinormal modes are generically associated with the photon ring of the black hole. This correspondence is valid for most cases in general relativity, but may not be true in other theories of gravity. In this paper, we consider the generalized energy-momentum squared gravity in which matter fields are non-minimally coupled to geometry. We investigate the axial perturbations of the charged black holes in this model, without assuming any explicit expression of the action functional. After obtaining the modified Klein-Gordon equation and the modified Maxwell equations, we perturb the gravitational equations and the modified Maxwell equations to derive the coupled master equations of the axial perturbations. In the presence of the non-minimal coupling between matter and geometry, the correspondence between the eikonal quasinormal modes and the photon ring is not satisfied in general. Also, the two coupled fields of the axial perturbations are found to propagate independently and they do not share the same quasinormal frequencies in the eikonal limit.
|
2209.13726
|
Giovanni Amelino-Camelia
|
Giovanni Amelino-Camelia, Maria Grazia Di Luca, Giulia Gubitosi,
Giacomo Rosati, Giacomo D'Amico
|
Could quantum gravity slow down neutrinos?
|
Latex, 5 pages
|
Nat Astron (2023)
|
10.1038/s41550-023-01993-z
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
In addition to its implications for astrophysics, the hunt for GRB neutrinos
could also be significant in quantum-gravity research, since they are excellent
probes of the microscopic fabric of spacetime. Some previous studies based on
IceCube neutrinos had found intriguing preliminary evidence that some of them
might be GRB neutrinos with travel times affected by quantum properties of
spacetime, with the noticeable feature that quantum spacetime would slow down
some of the neutrinos while others would be sped up. Recently the IceCube
collaboration revised significantly the estimates of the direction of
observation of their neutrinos, and we here investigate how the corrected
directional information affects the results of the previous
quantum-spacetime-inspired analyses. We find that there is now no evidence for
neutrinos sped up by quantum-spacetime properties, whereas the evidence for
neutrinos slowed down by quantum spacetime is even stronger than previously
found. Our most conservative estimates find a false alarm probability of less
than 1% for these "slow neutrinos", providing motivation for future studies on
larger data samples.
|
[
{
"created": "Tue, 27 Sep 2022 22:32:25 GMT",
"version": "v1"
}
] |
2023-07-13
|
[
[
"Amelino-Camelia",
"Giovanni",
""
],
[
"Di Luca",
"Maria Grazia",
""
],
[
"Gubitosi",
"Giulia",
""
],
[
"Rosati",
"Giacomo",
""
],
[
"D'Amico",
"Giacomo",
""
]
] |
In addition to its implications for astrophysics, the hunt for GRB neutrinos could also be significant in quantum-gravity research, since they are excellent probes of the microscopic fabric of spacetime. Some previous studies based on IceCube neutrinos had found intriguing preliminary evidence that some of them might be GRB neutrinos with travel times affected by quantum properties of spacetime, with the noticeable feature that quantum spacetime would slow down some of the neutrinos while others would be sped up. Recently the IceCube collaboration revised significantly the estimates of the direction of observation of their neutrinos, and we here investigate how the corrected directional information affects the results of the previous quantum-spacetime-inspired analyses. We find that there is now no evidence for neutrinos sped up by quantum-spacetime properties, whereas the evidence for neutrinos slowed down by quantum spacetime is even stronger than previously found. Our most conservative estimates find a false alarm probability of less than 1% for these "slow neutrinos", providing motivation for future studies on larger data samples.
|
2002.10262
|
Alexander Dolgov
|
A.D. Dolgov
|
Electromagnetic phenomena around black holes
|
6 pages, talk presented at 8th International Conference on New
Frontiers in Physics, 21-30 August, 2019, Conference Center of the Orthodox
Academy of Creta Crete, Greece
| null | null | null |
gr-qc astro-ph.CO
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Transition of gravitational waves, produced in the process of coalescence of
black hole binaries, into electromagnetic radiation in magnetic field is
discussed. The magnetic field is assumed to be created by rotating electrically
charged black holes. The process of electric charging of black holes due to
different mobilities of protons and electrons in the surrounding plasma is
described.
|
[
{
"created": "Fri, 21 Feb 2020 16:38:01 GMT",
"version": "v1"
}
] |
2020-02-25
|
[
[
"Dolgov",
"A. D.",
""
]
] |
Transition of gravitational waves, produced in the process of coalescence of black hole binaries, into electromagnetic radiation in magnetic field is discussed. The magnetic field is assumed to be created by rotating electrically charged black holes. The process of electric charging of black holes due to different mobilities of protons and electrons in the surrounding plasma is described.
|
2008.07416
|
Arick Shao
|
Alex McGill, Arick Shao
|
Null Geodesics and Improved Unique Continuation for Waves in
Asymptotically Anti-de Sitter Spacetimes
|
55 pages, 2 figures
| null |
10.1088/1361-6382/abcfd1
| null |
gr-qc math.AP
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We consider the question of whether solutions of Klein--Gordon equations on
asymptotically Anti-de Sitter spacetimes can be uniquely continued from the
conformal boundary. Positive answers were first given by the second author with
G. Holzegel, under suitable assumptions on the boundary geometry and with
boundary data imposed over a sufficiently long timespan. The key step was to
establish Carleman estimates for Klein--Gordon operators near the conformal
boundary.
In this article, we further improve upon the above-mentioned results. First,
we establish new Carleman estimates---and hence new unique continuation
results---for Klein--Gordon equations on a larger class of spacetimes, in
particular with more general boundary geometries. Second, we argue for the
optimality, in many respects, of our assumptions by connecting them to
trajectories of null geodesics near the conformal boundary; these geodesics
play a crucial role in the construction of counterexamples to unique
continuation. Finally, we develop a new covariant formalism that will be
useful---both presently and more generally beyond this article---for treating
tensorial objects with asymptotic limits at the conformal boundary.
|
[
{
"created": "Mon, 17 Aug 2020 15:41:38 GMT",
"version": "v1"
}
] |
2021-02-03
|
[
[
"McGill",
"Alex",
""
],
[
"Shao",
"Arick",
""
]
] |
We consider the question of whether solutions of Klein--Gordon equations on asymptotically Anti-de Sitter spacetimes can be uniquely continued from the conformal boundary. Positive answers were first given by the second author with G. Holzegel, under suitable assumptions on the boundary geometry and with boundary data imposed over a sufficiently long timespan. The key step was to establish Carleman estimates for Klein--Gordon operators near the conformal boundary. In this article, we further improve upon the above-mentioned results. First, we establish new Carleman estimates---and hence new unique continuation results---for Klein--Gordon equations on a larger class of spacetimes, in particular with more general boundary geometries. Second, we argue for the optimality, in many respects, of our assumptions by connecting them to trajectories of null geodesics near the conformal boundary; these geodesics play a crucial role in the construction of counterexamples to unique continuation. Finally, we develop a new covariant formalism that will be useful---both presently and more generally beyond this article---for treating tensorial objects with asymptotic limits at the conformal boundary.
|
gr-qc/9711033
|
Vladimir Dzhunushaliev
|
V.D. Dzhunushaliev
|
Multidimensional Gravity on the Principal Bundles
|
REVTEX, 13pages, 2 EPS figures
|
Gen.Rel.Grav. 30 (1998) 583
|
10.1023/A:1018818224423
| null |
gr-qc
| null |
The multidimensional gravity on the total space of principal bundle is
considered. In this theory the gauge fields arise as nondiagonal components of
multidimensional metric. The spherically symmetric and cosmology solutions for
gravity on SU(2) principal bundle are obtained. The static spherically
symmetric solution is wormhole-like solution located between two null surfaces,
in contrast to 4D Einstein-Yang-Mills theory where corresponding solution
(black hole) located outside of event horizon. Cosmology solution (at least
locally) has the bouncing off effect for spatial dimensions. In spirit of
Einstein these solutions are vacuum solutions without matter.
|
[
{
"created": "Mon, 10 Nov 1997 09:51:02 GMT",
"version": "v1"
}
] |
2015-06-25
|
[
[
"Dzhunushaliev",
"V. D.",
""
]
] |
The multidimensional gravity on the total space of principal bundle is considered. In this theory the gauge fields arise as nondiagonal components of multidimensional metric. The spherically symmetric and cosmology solutions for gravity on SU(2) principal bundle are obtained. The static spherically symmetric solution is wormhole-like solution located between two null surfaces, in contrast to 4D Einstein-Yang-Mills theory where corresponding solution (black hole) located outside of event horizon. Cosmology solution (at least locally) has the bouncing off effect for spatial dimensions. In spirit of Einstein these solutions are vacuum solutions without matter.
|
gr-qc/9903053
|
Bg Sidharth
|
B.G. Sidharth
|
Large Scale Structures in the Universe
|
2 pages, TeX
| null | null | null |
gr-qc
| null |
In this brief communication we show why superclusters would naturally arise
in the universe.
|
[
{
"created": "Sun, 14 Mar 1999 12:58:44 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Sidharth",
"B. G.",
""
]
] |
In this brief communication we show why superclusters would naturally arise in the universe.
|
1512.05453
|
Leo Stein
|
Robert McNees, Leo C. Stein, and Nicol\'as Yunes
|
Extremal Black Holes in Dynamical Chern-Simons Gravity
|
25+9 pages (single column), 10 figures, 1 table; matches published
version
|
Class. Quantum Grav. 33, 235013 (2016)
|
10.1088/0264-9381/33/23/235013
| null |
gr-qc astro-ph.HE hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
Rapidly rotating black hole solutions in theories beyond general relativity
play a key role in experimental gravity, as they allow us to compute
observables in extreme spacetimes that deviate from the predictions of general
relativity. Such solutions are often difficult to find in
beyond-general-relativity theories due to the inclusion of additional fields
that couple to the metric non-linearly and non-minimally. In this paper, we
consider rotating black hole solutions in one such theory, dynamical
Chern-Simons gravity, where the Einstein-Hilbert action is modified by the
introduction of a dynamical scalar field that couples to the metric through the
Pontryagin density. We treat dynamical Chern-Simons gravity as an effective
field theory and work in the decoupling limit, where corrections are treated as
small perturbations from general relativity. We perturb about the
maximally-rotating Kerr solution, the so-called extremal limit, and develop
mathematical insight into the analysis techniques needed to construct solutions
for generic spin. First we find closed-form, analytic expressions for the
extremal scalar field, and then determine the trace of the metric perturbation,
giving both in terms of Legendre decompositions. Retaining only the first three
and four modes in the Legendre representation of the scalar field and the
trace, respectively, suffices to ensure a fidelity of over 99% relative to full
numerical solutions. The leading-order mode in the Legendre expansion of the
trace of the metric perturbation contains a logarithmic divergence at the
extremal Kerr horizon, which is likely to be unimportant as it occurs inside
the perturbed dynamical Chern-Simons horizon. The techniques employed here
should enable the construction of analytic, closed-form expressions for the
scalar field and metric perturbations on a background with arbitrary rotation.
|
[
{
"created": "Thu, 17 Dec 2015 03:25:44 GMT",
"version": "v1"
},
{
"created": "Sun, 27 Nov 2016 01:14:56 GMT",
"version": "v2"
}
] |
2016-11-29
|
[
[
"McNees",
"Robert",
""
],
[
"Stein",
"Leo C.",
""
],
[
"Yunes",
"Nicolás",
""
]
] |
Rapidly rotating black hole solutions in theories beyond general relativity play a key role in experimental gravity, as they allow us to compute observables in extreme spacetimes that deviate from the predictions of general relativity. Such solutions are often difficult to find in beyond-general-relativity theories due to the inclusion of additional fields that couple to the metric non-linearly and non-minimally. In this paper, we consider rotating black hole solutions in one such theory, dynamical Chern-Simons gravity, where the Einstein-Hilbert action is modified by the introduction of a dynamical scalar field that couples to the metric through the Pontryagin density. We treat dynamical Chern-Simons gravity as an effective field theory and work in the decoupling limit, where corrections are treated as small perturbations from general relativity. We perturb about the maximally-rotating Kerr solution, the so-called extremal limit, and develop mathematical insight into the analysis techniques needed to construct solutions for generic spin. First we find closed-form, analytic expressions for the extremal scalar field, and then determine the trace of the metric perturbation, giving both in terms of Legendre decompositions. Retaining only the first three and four modes in the Legendre representation of the scalar field and the trace, respectively, suffices to ensure a fidelity of over 99% relative to full numerical solutions. The leading-order mode in the Legendre expansion of the trace of the metric perturbation contains a logarithmic divergence at the extremal Kerr horizon, which is likely to be unimportant as it occurs inside the perturbed dynamical Chern-Simons horizon. The techniques employed here should enable the construction of analytic, closed-form expressions for the scalar field and metric perturbations on a background with arbitrary rotation.
|
1810.11761
|
Saurya Das
|
Vasil Todorinov, Pasquale Bosso, Saurya Das
|
Relativistic Generalized Uncertainty Principle
|
6 pages, Revtex
|
Annals Phys. 405 (2019) 92-100
|
10.1016/j.aop.2019.03.014
| null |
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The Generalized Uncertainty Principle and the related minimum length are
normally considered in non-relativistic Quantum Mechanics. Extending it to
relativistic theories is important for having a Lorentz invariant minimum
length and for testing the modified Heisenberg principle at high energies.In
this paper, we formulate a relativistic Generalized Uncertainty Principle. We
then use this to write the modified Klein-Gordon, Schr\"odinger and Dirac
equations, and compute quantum gravity corrections to the relativistic hydrogen
atom, particle in a box, and the linear harmonic oscillator.
|
[
{
"created": "Sun, 28 Oct 2018 05:50:58 GMT",
"version": "v1"
}
] |
2021-06-11
|
[
[
"Todorinov",
"Vasil",
""
],
[
"Bosso",
"Pasquale",
""
],
[
"Das",
"Saurya",
""
]
] |
The Generalized Uncertainty Principle and the related minimum length are normally considered in non-relativistic Quantum Mechanics. Extending it to relativistic theories is important for having a Lorentz invariant minimum length and for testing the modified Heisenberg principle at high energies.In this paper, we formulate a relativistic Generalized Uncertainty Principle. We then use this to write the modified Klein-Gordon, Schr\"odinger and Dirac equations, and compute quantum gravity corrections to the relativistic hydrogen atom, particle in a box, and the linear harmonic oscillator.
|
gr-qc/9912014
|
Vesselin Petkov
|
Vesselin Petkov
|
Probing the anisotropic velocity of light in a gravitational field:
another test of general relativity
|
5 pages, LaTeX, small changes and reference added; epic.sty is
required (also available at http://alcor.concordia.ca/~vpetkov/epic.sty)
|
Chap. 7.6 of "Relativity and the Nature of Spacetime," 2nd ed
(Springer, 2009)
| null | null |
gr-qc
| null |
A corollary of general relativity that the average velocity of light between
two points in a gravitational field is anisotropic has been overlooked. It is
shown that this anisotropy can be probed by an experiment which constitutes
another test of general relativity.
|
[
{
"created": "Thu, 2 Dec 1999 21:27:52 GMT",
"version": "v1"
},
{
"created": "Fri, 3 Dec 1999 03:14:44 GMT",
"version": "v2"
},
{
"created": "Sat, 4 Dec 1999 06:02:22 GMT",
"version": "v3"
},
{
"created": "Sun, 19 Dec 1999 07:44:00 GMT",
"version": "v4"
},
{
"created": "Wed, 29 Dec 1999 02:03:22 GMT",
"version": "v5"
},
{
"created": "Sat, 1 Jan 2000 02:03:35 GMT",
"version": "v6"
},
{
"created": "Fri, 14 Jan 2000 03:09:27 GMT",
"version": "v7"
},
{
"created": "Sun, 31 Dec 2000 20:59:53 GMT",
"version": "v8"
}
] |
2011-11-18
|
[
[
"Petkov",
"Vesselin",
""
]
] |
A corollary of general relativity that the average velocity of light between two points in a gravitational field is anisotropic has been overlooked. It is shown that this anisotropy can be probed by an experiment which constitutes another test of general relativity.
|
0912.5164
|
Kensuke Homma
|
Yasunori Fujii and Kensuke Homma
|
A Laboratory Search for Dark Energy
|
10 pages, 2 figures
| null | null | null |
gr-qc hep-ph
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The discovery of the accelerating universe indicates strongly the presence of
a scalar field which is not only expected to solve today's version of the
cosmological constant problem, or the fine-tuning and the coincidence problems,
but also provides a way to understand dark energy. It has also been shown that
Jordan's scalar-tensor theory is now going to be re-discovered in the new
lights. In this letter we suggest a way to search for the extremely light
scalar field by means of a laboratory experiment on the low-energy
photon-photon interactions with the quasi-parallel incident beams.
|
[
{
"created": "Mon, 28 Dec 2009 12:51:27 GMT",
"version": "v1"
},
{
"created": "Wed, 24 Feb 2010 11:22:09 GMT",
"version": "v2"
}
] |
2010-02-24
|
[
[
"Fujii",
"Yasunori",
""
],
[
"Homma",
"Kensuke",
""
]
] |
The discovery of the accelerating universe indicates strongly the presence of a scalar field which is not only expected to solve today's version of the cosmological constant problem, or the fine-tuning and the coincidence problems, but also provides a way to understand dark energy. It has also been shown that Jordan's scalar-tensor theory is now going to be re-discovered in the new lights. In this letter we suggest a way to search for the extremely light scalar field by means of a laboratory experiment on the low-energy photon-photon interactions with the quasi-parallel incident beams.
|
1703.09525
|
Donato Bini
|
Donato Bini, Andrea Geralico and Robert T. Jantzen
|
Gyroscope precession along general timelike geodesics in a Kerr black
hole spacetime
|
20 pages, 5 figures, revtex macros used
|
Phys. Rev. D 95, 124022 (2017)
|
10.1103/PhysRevD.95.124022
| null |
gr-qc
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
The precession angular velocity of a gyroscope moving along a general
geodesic in the Kerr spacetime is analyzed using the geometric properties of
the spacetime. Natural frames along the gyroscope world line are explicitly
constructed by boosting frames adapted to fundamental observers. A novel
geometrical description is given to Marck's construction of a parallel
propagated orthonormal frame along a general geodesic, identifying and
clarifying the special role played by the Carter family of observers in this
general context, thus extending previous discussion for the equatorial plane
case.
|
[
{
"created": "Tue, 28 Mar 2017 12:07:22 GMT",
"version": "v1"
}
] |
2017-06-21
|
[
[
"Bini",
"Donato",
""
],
[
"Geralico",
"Andrea",
""
],
[
"Jantzen",
"Robert T.",
""
]
] |
The precession angular velocity of a gyroscope moving along a general geodesic in the Kerr spacetime is analyzed using the geometric properties of the spacetime. Natural frames along the gyroscope world line are explicitly constructed by boosting frames adapted to fundamental observers. A novel geometrical description is given to Marck's construction of a parallel propagated orthonormal frame along a general geodesic, identifying and clarifying the special role played by the Carter family of observers in this general context, thus extending previous discussion for the equatorial plane case.
|
gr-qc/9509034
| null |
K. S. Virbhadra
|
Energy and momentum of cylindrical gravitational waves. II
|
8 pages, LaTex, To appear in Pramana- J. Physics
|
Pramana 45 (1995) 215-219
|
10.1007/BF02848265
| null |
gr-qc astro-ph hep-th
| null |
Recently Nathan Rosen and the present author obtained the energy and momentum
densities of cylindrical gravitational waves in Einstein's prescription and
found them to be finite and reasonable. In the present paper we calculate the
same in prescriptions of Tolman as well as Landau and Lifshitz and discuss the
results.
|
[
{
"created": "Thu, 21 Sep 1995 13:20:00 GMT",
"version": "v1"
}
] |
2009-10-28
|
[
[
"Virbhadra",
"K. S.",
""
]
] |
Recently Nathan Rosen and the present author obtained the energy and momentum densities of cylindrical gravitational waves in Einstein's prescription and found them to be finite and reasonable. In the present paper we calculate the same in prescriptions of Tolman as well as Landau and Lifshitz and discuss the results.
|
1501.01644
|
Joel Berg\'e
|
Joel Berg\'e, Pierre Touboul, Manuel Rodrigues
|
Status of MICROSCOPE, a mission to test the Equivalence Principle in
space
|
Proceedings of LISA Symposium X; accepted for publication in Journal
of Physics: Conference Series
| null |
10.1088/1742-6596/610/1/012009
| null |
gr-qc astro-ph.IM
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
MICROSCOPE is a French Space Agency mission that aims to test the Weak
Equivalence Principle in space down to an accuracy of $10^{-15}$. This is two
orders of magnitude better than the current constraints, which will allow us to
test General Relativity as well as theories beyond General Relativity which
predict a possible Weak Equivalence Principle violation below $10^{-13}$. In
this communication, we describe the MICROSCOPE mission, its measurement
principle and instrument, and we give an update on its status. After a
successful instrument's commissioning, MICROSCOPE is on track for on-schedule
launch, expected in 2016.
|
[
{
"created": "Wed, 7 Jan 2015 21:07:42 GMT",
"version": "v1"
}
] |
2015-06-11
|
[
[
"Bergé",
"Joel",
""
],
[
"Touboul",
"Pierre",
""
],
[
"Rodrigues",
"Manuel",
""
]
] |
MICROSCOPE is a French Space Agency mission that aims to test the Weak Equivalence Principle in space down to an accuracy of $10^{-15}$. This is two orders of magnitude better than the current constraints, which will allow us to test General Relativity as well as theories beyond General Relativity which predict a possible Weak Equivalence Principle violation below $10^{-13}$. In this communication, we describe the MICROSCOPE mission, its measurement principle and instrument, and we give an update on its status. After a successful instrument's commissioning, MICROSCOPE is on track for on-schedule launch, expected in 2016.
|
gr-qc/0606091
|
Wlodzimierz Piechocki
|
Przemyslaw Malkiewicz and Wlodzimierz Piechocki
|
Probing the cosmological singularity with a particle
|
19 pages, 7 figures, revtex4, added references, version accepted for
publication in Class. Quantum Grav
|
Class.Quant.Grav. 23 (2006) 7045-7062
|
10.1088/0264-9381/23/23/026
| null |
gr-qc astro-ph hep-th quant-ph
| null |
We examine the transition of a particle across the singularity of the
compactified Milne (CM) space. Quantization of the phase space of a particle
and testing the quantum stability of its dynamics are consistent to one
another. One type of transition of a quantum particle is described by a quantum
state that is continuous at the singularity. It indicates the existence of a
deterministic link between the propagation of a particle before and after
crossing the singularity. Regularization of the CM space leads to the dynamics
similar to the dynamics in the de Sitter space. The CM space is a promising
model to describe the cosmological singularity deserving further investigation
by making use of strings and membranes.
|
[
{
"created": "Wed, 21 Jun 2006 15:54:23 GMT",
"version": "v1"
},
{
"created": "Mon, 9 Oct 2006 08:19:19 GMT",
"version": "v2"
}
] |
2009-11-11
|
[
[
"Malkiewicz",
"Przemyslaw",
""
],
[
"Piechocki",
"Wlodzimierz",
""
]
] |
We examine the transition of a particle across the singularity of the compactified Milne (CM) space. Quantization of the phase space of a particle and testing the quantum stability of its dynamics are consistent to one another. One type of transition of a quantum particle is described by a quantum state that is continuous at the singularity. It indicates the existence of a deterministic link between the propagation of a particle before and after crossing the singularity. Regularization of the CM space leads to the dynamics similar to the dynamics in the de Sitter space. The CM space is a promising model to describe the cosmological singularity deserving further investigation by making use of strings and membranes.
|
1701.07554
|
Andronikos Paliathanasis
|
N. Dimakis, Alex Giacomini and Andronikos Paliathanasis
|
Integrability from Point Symmetries in a family of Cosmological
Horndeski Lagrangians
|
13 pages; new material and discussion improved; version accepted for
publication by EPJC
| null |
10.1140/epjc/s10052-017-5029-9
| null |
gr-qc hep-th math-ph math.MP
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
For a family of Horndeski theories, formulated in terms of a generalized
Galileon model, we study the integrability of the field equations in a
Friedmann-Lema\^{\i}tre-Robertson-Walker spacetime. We are interested in point
transformations which leave invariant the field equations. Noether's theorem is
applied to determine the conservation laws for a family of models that belong
to the same general class. The cosmological scenarios with or without an extra
perfect fluid with constant equation of state parameter are the two important
cases of our study. \ The De Sitter universe and ideal gas solutions are
derived by using the invariant functions of the symmetry generators as a
demonstration of our result. Furthermore, we discuss the connection of the
different models under conformal transformations while we show that when the
Horndeski theory reduces to a canonical field the same holds for the conformal
equivalent theory. Finally we discuss how singular solutions provides
nonsingular universes in a different frame and vice versa.
|
[
{
"created": "Thu, 26 Jan 2017 02:42:01 GMT",
"version": "v1"
},
{
"created": "Mon, 27 Feb 2017 15:18:29 GMT",
"version": "v2"
},
{
"created": "Wed, 28 Jun 2017 14:08:51 GMT",
"version": "v3"
}
] |
2017-08-02
|
[
[
"Dimakis",
"N.",
""
],
[
"Giacomini",
"Alex",
""
],
[
"Paliathanasis",
"Andronikos",
""
]
] |
For a family of Horndeski theories, formulated in terms of a generalized Galileon model, we study the integrability of the field equations in a Friedmann-Lema\^{\i}tre-Robertson-Walker spacetime. We are interested in point transformations which leave invariant the field equations. Noether's theorem is applied to determine the conservation laws for a family of models that belong to the same general class. The cosmological scenarios with or without an extra perfect fluid with constant equation of state parameter are the two important cases of our study. \ The De Sitter universe and ideal gas solutions are derived by using the invariant functions of the symmetry generators as a demonstration of our result. Furthermore, we discuss the connection of the different models under conformal transformations while we show that when the Horndeski theory reduces to a canonical field the same holds for the conformal equivalent theory. Finally we discuss how singular solutions provides nonsingular universes in a different frame and vice versa.
|
2212.04414
|
Marius Adrian Oancea
|
Marius A. Oancea, Achal Kumar
|
Semiclassical analysis of Dirac fields on curved spacetime
| null |
Phys. Rev. D 107, 044029 (2023)
|
10.1103/PhysRevD.107.044029
| null |
gr-qc hep-th math-ph math.MP
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We present a semiclassical analysis for Dirac fields on an arbitrary
spacetime background and in the presence of a fixed electromagnetic field. Our
approach is based on a Wentzel-Kramers-Brillouin approximation, and the results
are analyzed at leading and next-to-leading order in the small expansion
parameter $\hbar$. Taking into account the spin-orbit coupling between the
internal and external degrees of freedom of wave packets, we derive effective
ray equations with spin-dependent terms. These equations describe the
gravitational spin Hall effect of localized Dirac wave packets. We treat both
massive and massless Dirac fields and show how a covariantly defined Berry
connection and the associated Berry curvature govern the semiclassical
dynamics. The gravitational spin Hall equations are shown to be particular
cases of the Mathisson-Papapetrou equations for spinning objects.
|
[
{
"created": "Thu, 8 Dec 2022 17:12:00 GMT",
"version": "v1"
},
{
"created": "Tue, 14 Feb 2023 19:26:26 GMT",
"version": "v2"
}
] |
2023-02-16
|
[
[
"Oancea",
"Marius A.",
""
],
[
"Kumar",
"Achal",
""
]
] |
We present a semiclassical analysis for Dirac fields on an arbitrary spacetime background and in the presence of a fixed electromagnetic field. Our approach is based on a Wentzel-Kramers-Brillouin approximation, and the results are analyzed at leading and next-to-leading order in the small expansion parameter $\hbar$. Taking into account the spin-orbit coupling between the internal and external degrees of freedom of wave packets, we derive effective ray equations with spin-dependent terms. These equations describe the gravitational spin Hall effect of localized Dirac wave packets. We treat both massive and massless Dirac fields and show how a covariantly defined Berry connection and the associated Berry curvature govern the semiclassical dynamics. The gravitational spin Hall equations are shown to be particular cases of the Mathisson-Papapetrou equations for spinning objects.
|
1206.0413
|
Willians Barreto
|
L. Herrera (UPV and UCV) and W. Barreto (ULA)
|
Electromagnetic radiation produces frame dragging
|
8 pages RevTex 4-1; updated version to appear in Physical Review D
|
Phys. Rev. D 86, 064014 (2012)
|
10.1103/PhysRevD.86.064014
| null |
gr-qc astro-ph.IM
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
It is shown that for a generic electrovacuum spacetime, electromagnetic
radiation produces vorticity of worldlines of observers in a Bondi--Sachs
frame. Such an effect (and the ensuing gyroscope precession with respect to the
lattice) which is a reminiscence of generation of vorticity by gravitational
radiation, may be linked to the nonvanishing of components of the Poynting and
the super--Poynting vectors on the planes othogonal to the vorticity vector.
The possible observational relevance of such an effect is commented.
|
[
{
"created": "Sun, 3 Jun 2012 00:17:02 GMT",
"version": "v1"
},
{
"created": "Mon, 6 Aug 2012 20:19:19 GMT",
"version": "v2"
}
] |
2015-06-05
|
[
[
"Herrera",
"L.",
"",
"UPV and UCV"
],
[
"Barreto",
"W.",
"",
"ULA"
]
] |
It is shown that for a generic electrovacuum spacetime, electromagnetic radiation produces vorticity of worldlines of observers in a Bondi--Sachs frame. Such an effect (and the ensuing gyroscope precession with respect to the lattice) which is a reminiscence of generation of vorticity by gravitational radiation, may be linked to the nonvanishing of components of the Poynting and the super--Poynting vectors on the planes othogonal to the vorticity vector. The possible observational relevance of such an effect is commented.
|
1603.00052
|
Peter Taylor
|
Abraham I. Harte, \'Eanna \'E. Flanagan and Peter Taylor
|
Self-forces on static bodies in arbitrary dimensions
| null |
Phys. Rev. D 93, 124054 (2016)
|
10.1103/PhysRevD.93.124054
| null |
gr-qc hep-th
|
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
|
We derive exact expressions for the scalar and electromagnetic self-forces
and self-torques acting on arbitrary static extended bodies in arbitrary static
spacetimes with any number of dimensions. Non-perturbatively, our results are
identical in all dimensions. Meaningful point particle limits are quite
different in different dimensions, however. These limits are defined and
evaluated, resulting in simple "regularization algorithms" which can be used in
concrete calculations. In these limits, self-interaction is shown to be
progressively less important in higher numbers of dimensions; it generically
competes in magnitude with increasingly high-order extended-body effects.
Conversely, we show that self-interaction effects can be relatively large in
$1+1$ and $2+1$ dimensions. Our motivations for this work are twofold: First,
no previous derivation of the self-force has been provided in arbitrary
dimensions, and heuristic arguments presented by different authors have
resulted in conflicting conclusions. Second, the static self-force problem in
arbitrary dimensions provides a valuable testbed with which to continue the
development of general, non-perturbative methods in the theory of motion.
Several new insights are obtained in this direction, including a significantly
improved understanding of the renormalization process. We also show that there
is considerable freedom to use different "effective fields" in the laws of
motion---a freedom which can be exploited to optimally simplify specific
problems. Different choices give rise to different inertias, gravitational
forces, and electromagnetic or scalar self-forces, but there is a sense in
which none of these quantities are individually accessible to experiment.
Certain combinations are observable, however, and these remain invariant under
all possible field redefinitions.
|
[
{
"created": "Mon, 29 Feb 2016 21:34:25 GMT",
"version": "v1"
}
] |
2016-06-29
|
[
[
"Harte",
"Abraham I.",
""
],
[
"Flanagan",
"Éanna É.",
""
],
[
"Taylor",
"Peter",
""
]
] |
We derive exact expressions for the scalar and electromagnetic self-forces and self-torques acting on arbitrary static extended bodies in arbitrary static spacetimes with any number of dimensions. Non-perturbatively, our results are identical in all dimensions. Meaningful point particle limits are quite different in different dimensions, however. These limits are defined and evaluated, resulting in simple "regularization algorithms" which can be used in concrete calculations. In these limits, self-interaction is shown to be progressively less important in higher numbers of dimensions; it generically competes in magnitude with increasingly high-order extended-body effects. Conversely, we show that self-interaction effects can be relatively large in $1+1$ and $2+1$ dimensions. Our motivations for this work are twofold: First, no previous derivation of the self-force has been provided in arbitrary dimensions, and heuristic arguments presented by different authors have resulted in conflicting conclusions. Second, the static self-force problem in arbitrary dimensions provides a valuable testbed with which to continue the development of general, non-perturbative methods in the theory of motion. Several new insights are obtained in this direction, including a significantly improved understanding of the renormalization process. We also show that there is considerable freedom to use different "effective fields" in the laws of motion---a freedom which can be exploited to optimally simplify specific problems. Different choices give rise to different inertias, gravitational forces, and electromagnetic or scalar self-forces, but there is a sense in which none of these quantities are individually accessible to experiment. Certain combinations are observable, however, and these remain invariant under all possible field redefinitions.
|
gr-qc/9709023
|
Jorge Pullin
|
Jorge Pullin
|
Matters of Gravity, the newsletter of the APS TG on gravitation
|
27 pages LaTeX, uses html.sty, available (now also in html!) at
http://vishnu.nirvana.phys.psu.edu/mog.html
| null | null |
MOG-10
|
gr-qc
| null |
Contents:
*News:
April 1997 Joint APS/AAPT Meeting, by Beverly Berger
The physics survey and committee on gravitational physics, by Jim Hartle
*Research Briefs:
Instability of rotating stars to axial perturbations, by Sharon Morsink
LIGO project status, by Stan Whitcomb
The Search for Frame-Dragging, by Clifford Will
*Conference Reports:
Conference of the Southern African Relativity Society, by Nigel Bishop
II Warszaw workshop on canonical and quantum gravity, by Carlo Rovelli
Alpbach summer school on fundamental physics in space, by Peter Bender
MG8, an experimentalists' summary, by Riley Newman and Peter Saulson
Amaldi Conference on Gravitational Waves, by M. Alessandra Papa
Santa Fe workshop on simplicial quantum gravity, by Lee Smolin
VII Canadian Conference on General Relativity, by David Hobill
|
[
{
"created": "Wed, 10 Sep 1997 19:49:09 GMT",
"version": "v1"
}
] |
2007-05-23
|
[
[
"Pullin",
"Jorge",
""
]
] |
Contents: *News: April 1997 Joint APS/AAPT Meeting, by Beverly Berger The physics survey and committee on gravitational physics, by Jim Hartle *Research Briefs: Instability of rotating stars to axial perturbations, by Sharon Morsink LIGO project status, by Stan Whitcomb The Search for Frame-Dragging, by Clifford Will *Conference Reports: Conference of the Southern African Relativity Society, by Nigel Bishop II Warszaw workshop on canonical and quantum gravity, by Carlo Rovelli Alpbach summer school on fundamental physics in space, by Peter Bender MG8, an experimentalists' summary, by Riley Newman and Peter Saulson Amaldi Conference on Gravitational Waves, by M. Alessandra Papa Santa Fe workshop on simplicial quantum gravity, by Lee Smolin VII Canadian Conference on General Relativity, by David Hobill
|
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