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1212.0484
Alexey Toporensky
D. M. Chirkov, A. V. Toporensky
On stability of power-law solution in multidimensional Gauss-Bonnet cosmology
23 pages with 6 figures
null
10.1134/S020228931304004X
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider dynamics of a flat anisotropic multidimensional cosmological model in Gauss-Bonnet gravity in the presence of a homogeneous magnetic field. In particular, we find conditions under which the known power-law vacuum solution can be an attractor for the case with non-zero magnetic field. We also describe a pa...
[ { "created": "Mon, 3 Dec 2012 18:42:04 GMT", "version": "v1" } ]
2015-06-12
[ [ "Chirkov", "D. M.", "" ], [ "Toporensky", "A. V.", "" ] ]
We consider dynamics of a flat anisotropic multidimensional cosmological model in Gauss-Bonnet gravity in the presence of a homogeneous magnetic field. In particular, we find conditions under which the known power-law vacuum solution can be an attractor for the case with non-zero magnetic field. We also describe a part...
gr-qc/9803004
Tsvi Piran
Shahar Hod and Tsvi Piran
Mass-Inflation in Dynamical Gravitational Collapse of a Charged Scalar-Field
Latex, 13 pages including 4 figures, Revtex.sty
Phys.Rev.Lett. 81 (1998) 1554-1557
10.1103/PhysRevLett.81.1554
null
gr-qc
null
We study the inner-structure of a charged black-hole which is formed from the gravitational collapse of a self-gravitating charged scalar-field. Starting with a regular spacetime, we follow the evolution through the formation of an apparent horizon, a Cauchy horizon and a final central singularity. We find a null, we...
[ { "created": "Sun, 1 Mar 1998 16:45:10 GMT", "version": "v1" } ]
2009-10-31
[ [ "Hod", "Shahar", "" ], [ "Piran", "Tsvi", "" ] ]
We study the inner-structure of a charged black-hole which is formed from the gravitational collapse of a self-gravitating charged scalar-field. Starting with a regular spacetime, we follow the evolution through the formation of an apparent horizon, a Cauchy horizon and a final central singularity. We find a null, weak...
2407.12974
David Keitel
David Keitel
False positives for gravitational lensing: the gravitational-wave perspective
14 pages, 2 figures, submitted to Philosophical Transactions of the Royal Society special issue on Multi-Messenger Gravitational Lensing
null
null
LIGO-P2400196
gr-qc astro-ph.HE physics.data-an
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
For the first detection of a novel astrophysical phenomenon, scientific standards are particularly high. Especially in a multi-messenger context, there are also opportunity costs to follow-up observations on any detection claims. So in searching for the still elusive lensed gravitational waves, care needs to be taken...
[ { "created": "Wed, 17 Jul 2024 19:41:35 GMT", "version": "v1" } ]
2024-07-19
[ [ "Keitel", "David", "" ] ]
For the first detection of a novel astrophysical phenomenon, scientific standards are particularly high. Especially in a multi-messenger context, there are also opportunity costs to follow-up observations on any detection claims. So in searching for the still elusive lensed gravitational waves, care needs to be taken i...
1510.02859
Xin-Zhou Li
Ping Xi and Ping Li
Reexamining generalized Chaplygin gas with the sign-changeable interaction
6 pages, 7figures
Astrophys Space Sci 360 (2015) 3
10.1007/s10509-015-2512-3
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we reexamine the generalized Chaplygin gas (GCG) cosmology with the sign-changeable interaction. The dynamical analysis show that there exists de-Sitter attractors in this model, which means that the late-time behaviors of the model is insensitive to the initial condition and thus alleviates the coinci...
[ { "created": "Sat, 10 Oct 2015 00:42:16 GMT", "version": "v1" } ]
2015-10-13
[ [ "Xi", "Ping", "" ], [ "Li", "Ping", "" ] ]
In this paper, we reexamine the generalized Chaplygin gas (GCG) cosmology with the sign-changeable interaction. The dynamical analysis show that there exists de-Sitter attractors in this model, which means that the late-time behaviors of the model is insensitive to the initial condition and thus alleviates the coincide...
0806.1277
Terry Pilling
Richard T Hammond and Terry Pilling
Dark Entropy
7 pages, 1 figure
null
null
null
gr-qc astro-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We examine the consequences of a universe with a non-constant cosmological term in Einstein's equations and find that the Bianchi identities reduce to the first law of thermodynamics when cosmological term is identified as being proportional to the entropy density of the universe. This means that gravitating dark ene...
[ { "created": "Sat, 7 Jun 2008 11:05:09 GMT", "version": "v1" }, { "created": "Thu, 4 Sep 2008 18:54:40 GMT", "version": "v2" } ]
2008-09-04
[ [ "Hammond", "Richard T", "" ], [ "Pilling", "Terry", "" ] ]
We examine the consequences of a universe with a non-constant cosmological term in Einstein's equations and find that the Bianchi identities reduce to the first law of thermodynamics when cosmological term is identified as being proportional to the entropy density of the universe. This means that gravitating dark energ...
1909.08420
Hirotaka Yoshino
Hirotaka Yoshino, Keisuke Izumi, Tetsuya Shiromizu, Yoshimune Tomikawa
Transversely trapping surfaces: Dynamical version
34 pages, 10 figures, figures improved, minor corrections, published version
Prog. Theor. Exp. Phys. (2020) 023E02
10.1093/ptep/ptz161
OCU-PHYS-510, AP-GR-157
gr-qc astro-ph.GA
http://creativecommons.org/licenses/by/4.0/
We propose new concepts, a dynamically transversely trapping surface (DTTS) and a marginally DTTS, as indicators for a strong gravity region. A DTTS is defined as a two-dimensional closed surface on a spacelike hypersurface such that photons emitted from arbitrary points on it in transverse directions are accelerated...
[ { "created": "Wed, 18 Sep 2019 12:57:42 GMT", "version": "v1" }, { "created": "Tue, 25 Feb 2020 09:05:43 GMT", "version": "v2" } ]
2020-02-26
[ [ "Yoshino", "Hirotaka", "" ], [ "Izumi", "Keisuke", "" ], [ "Shiromizu", "Tetsuya", "" ], [ "Tomikawa", "Yoshimune", "" ] ]
We propose new concepts, a dynamically transversely trapping surface (DTTS) and a marginally DTTS, as indicators for a strong gravity region. A DTTS is defined as a two-dimensional closed surface on a spacelike hypersurface such that photons emitted from arbitrary points on it in transverse directions are acceleratedly...
1110.1310
Plyatsko Roman
Roman Plyatsko, Oleksandr Stefanyshyn, Mykola Fenyk
Highly relativistic spinning particle starting near $r_{ph}^{(-)}$ in a Kerr field
10 pages, 12 figures
Phys. Rev. D 82, 044015 (2010)
10.1103/PhysRevD.82.044015
null
gr-qc astro-ph.HE hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Using the Mathisson-Papapetrou-Dixon (MPD) equations, we investigate the trajectories of a spinning particle starting near $r_{ph}^{(-)}$ in a Kerr field and moving with the velocity close to the velocity of light ($r_{ph}^{(-)}$ is the Boyer-Lindquist radial coordinate of the counter-rotation circular photon orbits)...
[ { "created": "Thu, 6 Oct 2011 16:14:01 GMT", "version": "v1" } ]
2015-05-30
[ [ "Plyatsko", "Roman", "" ], [ "Stefanyshyn", "Oleksandr", "" ], [ "Fenyk", "Mykola", "" ] ]
Using the Mathisson-Papapetrou-Dixon (MPD) equations, we investigate the trajectories of a spinning particle starting near $r_{ph}^{(-)}$ in a Kerr field and moving with the velocity close to the velocity of light ($r_{ph}^{(-)}$ is the Boyer-Lindquist radial coordinate of the counter-rotation circular photon orbits). ...
0810.4914
Laura Mersini-Houghton
L.Mersini-Houghton and F.Adams
Limitations of anthropic predictions for the cosmological constant $\Lambda$: Cosmic Heat Death of Anthropic Observers
7pgs, published
Class.Quant.Grav.25:165002,2008
10.1088/0264-9381/25/16/165002
null
gr-qc astro-ph hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper investigates anthropic bounds on the vacuum energy $\Lambda$. We first consider the possibility of cosmic observers existing at any random time (including the future) for constant $\Lambda$, and take into account the suppression of new structure formation as the universe approaches its eternal DeSitter (DS...
[ { "created": "Mon, 27 Oct 2008 19:41:08 GMT", "version": "v1" } ]
2009-01-22
[ [ "Mersini-Houghton", "L.", "" ], [ "Adams", "F.", "" ] ]
This paper investigates anthropic bounds on the vacuum energy $\Lambda$. We first consider the possibility of cosmic observers existing at any random time (including the future) for constant $\Lambda$, and take into account the suppression of new structure formation as the universe approaches its eternal DeSitter (DS) ...
gr-qc/0507140
Stephen R. Lau
Stephen R. Lau
Analytic structure of radiation boundary kernels for blackhole perturbations
revtex4, 14 pages, 12 figures, 3 tables
J.Math.Phys. 46 (2005) 102503
10.1063/1.2073287
null
gr-qc
null
Exact outer boundary conditions for gravitational perturbations of the Schwarzschild metric feature integral convolution between a time-domain boundary kernel and each radiative mode of the perturbation. For both axial (Regge-Wheeler) and polar (Zerilli) perturbations, we study the Laplace transform of such kernels a...
[ { "created": "Fri, 29 Jul 2005 17:35:36 GMT", "version": "v1" } ]
2009-11-11
[ [ "Lau", "Stephen R.", "" ] ]
Exact outer boundary conditions for gravitational perturbations of the Schwarzschild metric feature integral convolution between a time-domain boundary kernel and each radiative mode of the perturbation. For both axial (Regge-Wheeler) and polar (Zerilli) perturbations, we study the Laplace transform of such kernels as ...
0710.0606
Balakin Alexander
A. B. Balakin
Extended Einstein-Maxwell model
27 pages
Grav.Cosmol.13:163-177,2007
null
null
gr-qc astro-ph hep-th
null
A self-consistent extended Einstein-Maxwell model for relativistic non-stationary polarizable-magnetizable anisotropic media is presented. Based on the analogy with relativistic extended irreversible (transient) thermodynamics, the extended constitutive equations for the electrodynamics of continua are formulated phe...
[ { "created": "Tue, 2 Oct 2007 19:24:25 GMT", "version": "v1" } ]
2008-11-26
[ [ "Balakin", "A. B.", "" ] ]
A self-consistent extended Einstein-Maxwell model for relativistic non-stationary polarizable-magnetizable anisotropic media is presented. Based on the analogy with relativistic extended irreversible (transient) thermodynamics, the extended constitutive equations for the electrodynamics of continua are formulated pheno...
2107.01648
Matthew Robbins
Matthew P. G. Robbins and Robert B. Mann
Anti-Hawking Phenomena around a Rotating BTZ Black Hole
10 pages, 7 figures
null
10.1103/PhysRevD.106.045018
null
gr-qc
http://creativecommons.org/licenses/by/4.0/
In both flat and curved spacetimes, there are weak and strong versions of the anti-Unruh/anti-Hawking effects, in which the KMS field temperature is anti-correlated with the response of a detector and its inferred temperature. We investigate for the first time the effects on the weak and strong anti-Hawking effects f...
[ { "created": "Sun, 4 Jul 2021 14:30:55 GMT", "version": "v1" } ]
2022-08-31
[ [ "Robbins", "Matthew P. G.", "" ], [ "Mann", "Robert B.", "" ] ]
In both flat and curved spacetimes, there are weak and strong versions of the anti-Unruh/anti-Hawking effects, in which the KMS field temperature is anti-correlated with the response of a detector and its inferred temperature. We investigate for the first time the effects on the weak and strong anti-Hawking effects for...
2202.11708
Sara Kanzi
Sara Kanzi, \.Izzet Sakall{\i}
Reply to "Comment on 'Greybody radiation and quasinormal modes of Kerr-like black hole in Bumblebee gravity model' "
null
EUROPEAN PHYSICAL JOURNAL C 82, 93 (2022)
10.1140/epjc/s10052-022-10044-2
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In our recent study Ref. [1]: Eur. Phys. J. C 81, 501 (2021) , the main goal was to reveal the Lorentz symmetry breaking (LSB) effect in the rotating black holes via the greybody factor and quasinormal mode analyzes. Ding et al. [2] Kerr-like black hole solution of the bumblebee gravity model used in our paper [1] ha...
[ { "created": "Wed, 23 Feb 2022 12:27:56 GMT", "version": "v1" } ]
2022-06-22
[ [ "Kanzi", "Sara", "" ], [ "Sakallı", "İzzet", "" ] ]
In our recent study Ref. [1]: Eur. Phys. J. C 81, 501 (2021) , the main goal was to reveal the Lorentz symmetry breaking (LSB) effect in the rotating black holes via the greybody factor and quasinormal mode analyzes. Ding et al. [2] Kerr-like black hole solution of the bumblebee gravity model used in our paper [1] has ...
1808.07863
Kartik Prabhu
Kartik Prabhu
Conservation of asymptotic charges from past to future null infinity: Maxwell fields
v3: M=Misner in ADM; author thanks D for this correction! v2: references updated, minor typos fixed, few explanatory comments added (published in JHEP) v1: 33 pages, 2 figures
JHEP 2018 (2018) 113
10.1007/JHEP10(2018)113
null
gr-qc hep-th math-ph math.MP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
On any asymptotically-flat spacetime, we show that the asymptotic symmetries and charges of Maxwell fields on past null infinity can be related to those on future null infinity as recently proposed by Strominger. We extend the covariant formalism of Ashtekar and Hansen by constructing a 3-manifold of both null and sp...
[ { "created": "Thu, 23 Aug 2018 17:51:56 GMT", "version": "v1" }, { "created": "Wed, 17 Oct 2018 09:42:37 GMT", "version": "v2" }, { "created": "Thu, 18 Oct 2018 19:08:32 GMT", "version": "v3" } ]
2018-10-22
[ [ "Prabhu", "Kartik", "" ] ]
On any asymptotically-flat spacetime, we show that the asymptotic symmetries and charges of Maxwell fields on past null infinity can be related to those on future null infinity as recently proposed by Strominger. We extend the covariant formalism of Ashtekar and Hansen by constructing a 3-manifold of both null and spat...
1702.01603
Andronikos Paliathanasis
N. Dimakis, Alex Giacomini, Sameerah Jamal, Genly Leon and Andronikos Paliathanasis
Noether symmetries and stability of ideal gas solution in Galileon Cosmology
14 pages, 4 figures; discussion improved; to appear in Phys. Rev. D
Phys. Rev. D 95, 064031 (2017)
10.1103/PhysRevD.95.064031
null
gr-qc astro-ph.CO hep-th math-ph math.MP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A class of generalized Galileon cosmological models, which can be described by a point-like Lagrangian, is considered in order to utilize Noether's Theorem to determine conservation laws for the field equations. In the Friedmann-Lema\^itre-Robertson-Walker universe, the existence of a nontrivial conservation law indi...
[ { "created": "Mon, 6 Feb 2017 13:11:32 GMT", "version": "v1" }, { "created": "Wed, 1 Mar 2017 19:05:17 GMT", "version": "v2" }, { "created": "Fri, 3 Mar 2017 15:21:50 GMT", "version": "v3" } ]
2017-03-23
[ [ "Dimakis", "N.", "" ], [ "Giacomini", "Alex", "" ], [ "Jamal", "Sameerah", "" ], [ "Leon", "Genly", "" ], [ "Paliathanasis", "Andronikos", "" ] ]
A class of generalized Galileon cosmological models, which can be described by a point-like Lagrangian, is considered in order to utilize Noether's Theorem to determine conservation laws for the field equations. In the Friedmann-Lema\^itre-Robertson-Walker universe, the existence of a nontrivial conservation law indica...
1701.06892
Muhammad Zubair
M. Zubair, Farzana Kousar, Saira Waheed
Reconstruction of Scalar Potentials in $f(R,R_{\alpha\beta} R^{\alpha\beta},\phi)$ theory of gravity
30 pages, 3 figures
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we explore the nature of scalar field potential in $f(R, R_{\alpha\beta} R^{\alpha\beta},\phi)$ gravity using a well-motivated reconstruction scheme for flat FRW geometry. The beauty of this scheme lies in the assumption that the Hubble parameter can be expressed in terms of scalar field and vice versa...
[ { "created": "Tue, 17 Jan 2017 09:07:29 GMT", "version": "v1" } ]
2017-01-25
[ [ "Zubair", "M.", "" ], [ "Kousar", "Farzana", "" ], [ "Waheed", "Saira", "" ] ]
In this paper, we explore the nature of scalar field potential in $f(R, R_{\alpha\beta} R^{\alpha\beta},\phi)$ gravity using a well-motivated reconstruction scheme for flat FRW geometry. The beauty of this scheme lies in the assumption that the Hubble parameter can be expressed in terms of scalar field and vice versa. ...
2405.19467
Mohamed Ibrahim Nouh
Mohamed S. Aboueisha, Mohamed I. Nouh, Emad A-B. Abdel-Salam. Tarek M. Kamel, Mohamed M. Beheary and Kamel A. K. Gadallah
Analysis of the Fractional Relativistic Polytropic Gas Sphere
null
Scientific Reports, 2023, 13, 14304
null
null
gr-qc astro-ph.SR
http://creativecommons.org/licenses/by/4.0/
Many stellar configurations, including white dwarfs, neutron stars, black holes, supermassive stars, and star clusters, rely on relativistic effects. The Tolman-Oppenheimer-Volkoff (TOV) equation of the polytropic gas sphere is ultimately a hydrostatic equilibrium equation developed from the general relativity framew...
[ { "created": "Wed, 29 May 2024 19:24:54 GMT", "version": "v1" } ]
2024-05-31
[ [ "Aboueisha", "Mohamed S.", "" ], [ "Nouh", "Mohamed I.", "" ], [ "Kamel", "Emad A-B. Abdel-Salam. Tarek M.", "" ], [ "Beheary", "Mohamed M.", "" ], [ "Gadallah", "Kamel A. K.", "" ] ]
Many stellar configurations, including white dwarfs, neutron stars, black holes, supermassive stars, and star clusters, rely on relativistic effects. The Tolman-Oppenheimer-Volkoff (TOV) equation of the polytropic gas sphere is ultimately a hydrostatic equilibrium equation developed from the general relativity framewor...
1901.01202
Sam Dolan Dr
Sam R. Dolan
Comment on "Geodesic dynamics on Chazy-Curzon spacetimes"
7 pages, 1 figure. See also arXiv:1812.08663
null
null
null
gr-qc nlin.CD
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The recent numerical results of Dubeibe et al. [arXiv:1812.08663] were interpreted as hinting at the existence of a fourth constant of motion (Carter's constant) for geodesics on Chazy-Curzon spacetimes. Here we show that, to the contrary, the geodesic dynamics of the single-particle Chazy-Curzon spacetime exhibit fe...
[ { "created": "Fri, 4 Jan 2019 16:43:38 GMT", "version": "v1" } ]
2019-01-07
[ [ "Dolan", "Sam R.", "" ] ]
The recent numerical results of Dubeibe et al. [arXiv:1812.08663] were interpreted as hinting at the existence of a fourth constant of motion (Carter's constant) for geodesics on Chazy-Curzon spacetimes. Here we show that, to the contrary, the geodesic dynamics of the single-particle Chazy-Curzon spacetime exhibit feat...
2305.08554
Jose Luis Jaramillo
Jos\'e Luis Jaramillo, Badri Krishnan, Carlos F. Sopuerta
Universality in Binary Black Hole Dynamics: An Integrability Conjecture
17 pages, no figures. Essay awarded a honorable mention in the 2023 Gravity Research Foundation essay competition
null
null
null
gr-qc hep-th math-ph math.MP nlin.SI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The waveform of a binary black hole coalescence appears to be both simple and universal. In this essay we argue that the dynamics should admit a separation into 'fast and slow' degrees of freedom, such that the latter are described by an integrable system of equations, accounting for the simplicity and universality o...
[ { "created": "Mon, 15 May 2023 11:33:21 GMT", "version": "v1" } ]
2023-05-16
[ [ "Jaramillo", "José Luis", "" ], [ "Krishnan", "Badri", "" ], [ "Sopuerta", "Carlos F.", "" ] ]
The waveform of a binary black hole coalescence appears to be both simple and universal. In this essay we argue that the dynamics should admit a separation into 'fast and slow' degrees of freedom, such that the latter are described by an integrable system of equations, accounting for the simplicity and universality of ...
2203.13515
Francesco Sannino
Emanuele Binetti, Manuel Del Piano, Stefan Hohenegger, Franco Pezzella, Francesco Sannino
The Effective Theory of Quantum Black Holes
Revised version matching the published one
null
10.1103/PhysRevD.106.046006
CERN-TH-2022-048
gr-qc hep-ph hep-th
http://creativecommons.org/licenses/by/4.0/
We explore the quantum nature of black holes by introducing an effective framework that takes into account deviations from the classical results. The approach is based on introducing quantum corrections to the classical Schwarzschild geometry in a way that is consistent with the physical scales of the black hole and ...
[ { "created": "Fri, 25 Mar 2022 09:04:40 GMT", "version": "v1" }, { "created": "Mon, 18 Apr 2022 07:25:14 GMT", "version": "v2" }, { "created": "Sat, 6 Aug 2022 15:04:11 GMT", "version": "v3" } ]
2022-09-14
[ [ "Binetti", "Emanuele", "" ], [ "Del Piano", "Manuel", "" ], [ "Hohenegger", "Stefan", "" ], [ "Pezzella", "Franco", "" ], [ "Sannino", "Francesco", "" ] ]
We explore the quantum nature of black holes by introducing an effective framework that takes into account deviations from the classical results. The approach is based on introducing quantum corrections to the classical Schwarzschild geometry in a way that is consistent with the physical scales of the black hole and it...
2005.03434
Jo\~ao L. Costa
Jo\~ao L. Costa
The formation of trapped surfaces in the gravitational collapse of spherically symmetric scalar fields with a positive cosmological constant
18 pages
null
null
null
gr-qc math.AP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Given spherically symmetric characteristic initial data for the Einstein-scalar field system with a positive cosmological constant, we provide a criterion, in terms of the dimensionless size and dimensionless renormalized mass content of an annular region of the data, for the formation of a future trapped surface. Th...
[ { "created": "Thu, 7 May 2020 13:03:27 GMT", "version": "v1" } ]
2020-05-08
[ [ "Costa", "João L.", "" ] ]
Given spherically symmetric characteristic initial data for the Einstein-scalar field system with a positive cosmological constant, we provide a criterion, in terms of the dimensionless size and dimensionless renormalized mass content of an annular region of the data, for the formation of a future trapped surface. This...
1512.07279
Artyom Astashenok V
A.V. Astashenok and S.D. Odintsov
From neutron stars to quark stars in mimetic gravity
13 pages, 6 figures, 3 tables
Phys. Rev. D 94, 063008 (2016)
10.1103/PhysRevD.94.063008
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Realistic models of neutron and quark stars in the framework of mimetic gravity with Lagrange multiplier constraint are presented. We discuss the effect of mimetic scalar aiming to describe dark matter on mass-radius relation and the moment of inertia for slowly rotating relativistic stars. The mass-radius relation a...
[ { "created": "Tue, 22 Dec 2015 22:06:34 GMT", "version": "v1" } ]
2016-09-28
[ [ "Astashenok", "A. V.", "" ], [ "Odintsov", "S. D.", "" ] ]
Realistic models of neutron and quark stars in the framework of mimetic gravity with Lagrange multiplier constraint are presented. We discuss the effect of mimetic scalar aiming to describe dark matter on mass-radius relation and the moment of inertia for slowly rotating relativistic stars. The mass-radius relation and...
gr-qc/9904037
Emulsion-Lab
S. Q. Wu and X. Cai
Exact Solutions to Sourceless Charged Massive Scalar Field Equation on Kerr-Newman Background
22 Pages, in LaTex, no figure, to appear in J. Math. Phys
J.Math.Phys. 40 (1999) 4538-4548
10.1063/1.532985
null
gr-qc
null
The separated radial part of a sourceless massive complex scalar field equation on the Kerr-Newman black hole background is shown to be a generalized spin-weighted spheroidal wave equation of imaginary number order. While the separated angular part is an ordinary spheroidal wave equation. General exact solutions in i...
[ { "created": "Thu, 15 Apr 1999 04:19:19 GMT", "version": "v1" } ]
2015-06-25
[ [ "Wu", "S. Q.", "" ], [ "Cai", "X.", "" ] ]
The separated radial part of a sourceless massive complex scalar field equation on the Kerr-Newman black hole background is shown to be a generalized spin-weighted spheroidal wave equation of imaginary number order. While the separated angular part is an ordinary spheroidal wave equation. General exact solutions in int...
2402.14171
Marc Casals
Christiane Klein, Mojgan Soltani, Marc Casals and Stefan Hollands
Infinite quantum twisting at the Cauchy horizon of rotating black holes
5 pages of main text plus 10 pages of Supplemental Material (merged in one single file, in this version), 9 figures in total. Published in Phys. Rev. Lett
Phys. Rev. Lett. 132, 121501 (2024)
10.1103/PhysRevLett.132.121501
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a numerical calculation of the expectation value of the quantum angular-momentum current flux density for a scalar field in the Unruh state near the inner horizon of a Kerr-de Sitter black hole. Our results indicate that this flux diverges as $V_-^{-1}$ in a suitable Kruskal coordinate such that $V_-=0$ at...
[ { "created": "Wed, 21 Feb 2024 23:20:07 GMT", "version": "v1" }, { "created": "Mon, 25 Mar 2024 23:05:46 GMT", "version": "v2" } ]
2024-03-27
[ [ "Klein", "Christiane", "" ], [ "Soltani", "Mojgan", "" ], [ "Casals", "Marc", "" ], [ "Hollands", "Stefan", "" ] ]
We present a numerical calculation of the expectation value of the quantum angular-momentum current flux density for a scalar field in the Unruh state near the inner horizon of a Kerr-de Sitter black hole. Our results indicate that this flux diverges as $V_-^{-1}$ in a suitable Kruskal coordinate such that $V_-=0$ at t...
1510.05522
Peter K.F. Kuhfittig
Peter K.F. Kuhfittig
Stable wormholes on a noncommutative-geometry background admitting a one-parameter group of conformal motions
12 pages, 1 figure
Indian J. Phys., 90(7), 837-842 (2016)
10.1007/s12648-015-0812-7
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
When Morris and Thorne first proposed the possible existence of traversable wormholes, they adopted the following strategy: maintain complete control over the geometry, thereby leaving open the determination of the stress-energy tensor. In this paper we determine this tensor by starting with a noncommutative-geometry...
[ { "created": "Mon, 19 Oct 2015 15:14:38 GMT", "version": "v1" }, { "created": "Mon, 23 May 2016 18:33:56 GMT", "version": "v2" } ]
2016-05-24
[ [ "Kuhfittig", "Peter K. F.", "" ] ]
When Morris and Thorne first proposed the possible existence of traversable wormholes, they adopted the following strategy: maintain complete control over the geometry, thereby leaving open the determination of the stress-energy tensor. In this paper we determine this tensor by starting with a noncommutative-geometry b...
1712.01404
Nelson Velandia
Nelson Velandia-Heredia and Juan Manuel Tejeiro-Sarmiento
Numerical solution of Mathisson-Papapetrou-Dixon equations for spinning test particles in a Kerr metric
17 pages, 2 figures. arXiv admin note: substantial text overlap with arXiv:1609.03630
Momento, N\'umero 57, p.60-85, 2018
10.15446/mo.n57.73391
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this work we calculate some estimations of the gravitomagnetic clock effect, taking into consideration not only the rotating gravitational field of the central mass, but also the spin of the test particle, obtaining values for $\Delta t=t_{+}-t_{-}=2.5212079035\times10^{-8} \textrm{s}$. We use the formulation of M...
[ { "created": "Mon, 4 Dec 2017 23:00:19 GMT", "version": "v1" }, { "created": "Sat, 7 Apr 2018 22:31:43 GMT", "version": "v2" } ]
2018-07-18
[ [ "Velandia-Heredia", "Nelson", "" ], [ "Tejeiro-Sarmiento", "Juan Manuel", "" ] ]
In this work we calculate some estimations of the gravitomagnetic clock effect, taking into consideration not only the rotating gravitational field of the central mass, but also the spin of the test particle, obtaining values for $\Delta t=t_{+}-t_{-}=2.5212079035\times10^{-8} \textrm{s}$. We use the formulation of Mat...
1001.4173
Salvatore Capozziello
S. Capozziello, M. De Laurentis, D. Vernieri
Neutrino oscillation phase dynamically induced by f(R)-gravity
4 pages
null
10.1142/S0217732310033025
null
gr-qc astro-ph.HE hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The gravitational phase shift of neutrino oscillation can be discussed in the framework of f(R)-gravity. We show that the shift of quantum mechanical phase can depend on the given f(R)-theory that we choose. This fact is general and could constitute a fundamental test to discriminate among the various alternative rel...
[ { "created": "Sat, 23 Jan 2010 17:11:58 GMT", "version": "v1" } ]
2015-05-18
[ [ "Capozziello", "S.", "" ], [ "De Laurentis", "M.", "" ], [ "Vernieri", "D.", "" ] ]
The gravitational phase shift of neutrino oscillation can be discussed in the framework of f(R)-gravity. We show that the shift of quantum mechanical phase can depend on the given f(R)-theory that we choose. This fact is general and could constitute a fundamental test to discriminate among the various alternative relat...
gr-qc/0104055
null
S. Q. Wu and X. Cai
Hawking Radiation of Dirac Particles in a Variable-mass Kerr Space-time
12 pages in 12pt Revtex, no figure, to appear in Gen. Rel. Grav. Vol.33, No.7 (2001)
Gen.Rel.Grav. 33 (2001) 1181-1195; Erratum-ibid. 34 (2002) 2019-2019
10.1023/A:1012033317604
null
gr-qc
null
Hawking effect of Dirac particles in a variable-mass Kerr space-time is investigated by using a method called as the generalized tortoise coordinate transformation. The location and the temperature of the event horizon of the non-stationary Kerr black hole are derived. It is shown that the temperature and the shape o...
[ { "created": "Wed, 18 Apr 2001 02:29:07 GMT", "version": "v1" } ]
2015-06-25
[ [ "Wu", "S. Q.", "" ], [ "Cai", "X.", "" ] ]
Hawking effect of Dirac particles in a variable-mass Kerr space-time is investigated by using a method called as the generalized tortoise coordinate transformation. The location and the temperature of the event horizon of the non-stationary Kerr black hole are derived. It is shown that the temperature and the shape of ...
gr-qc/9902006
Oscar Alejandro Reula
Oscar A. Reula
Exponential Decay for Small Non-Linear Perturbations of Expanding Flat Homogeneous Cosmologies
null
Phys. Rev. D 60, 083507 (1999)
10.1103/PhysRevD.60.083507
FaMAF-GRG: 1/99
gr-qc
null
It is shown that during expanding phases of flat homogeneous cosmologies all small enough non-linear perturbations decay exponentially. This result holds for a large class of perfect fluid equations of state, but notably not for very ``stiff'' fluids as the pure radiation case.
[ { "created": "Mon, 1 Feb 1999 17:25:00 GMT", "version": "v1" } ]
2016-08-25
[ [ "Reula", "Oscar A.", "" ] ]
It is shown that during expanding phases of flat homogeneous cosmologies all small enough non-linear perturbations decay exponentially. This result holds for a large class of perfect fluid equations of state, but notably not for very ``stiff'' fluids as the pure radiation case.
0704.1685
Xin-Zhou Li
Xing-hua Jin, Xin-zhou Li and Dao-jun Liu
Gravitating Global k-monopole
9 pages, 2 figures, references added, typos corrected, accepted by Class. Quantum Grav
Class.Quant.Grav.24:2773-2780,2007
10.1088/0264-9381/24/11/001
null
gr-qc
null
A gravitating global k-monopole produces a tiny gravitational field outside the core in addition to a solid angular deficit in the k-field theory. As a new feature, the gravitational field can be attractive or repulsive depending on the non-canonical kinetic term.
[ { "created": "Fri, 13 Apr 2007 01:48:38 GMT", "version": "v1" }, { "created": "Wed, 18 Apr 2007 03:18:19 GMT", "version": "v2" } ]
2008-11-26
[ [ "Jin", "Xing-hua", "" ], [ "Li", "Xin-zhou", "" ], [ "Liu", "Dao-jun", "" ] ]
A gravitating global k-monopole produces a tiny gravitational field outside the core in addition to a solid angular deficit in the k-field theory. As a new feature, the gravitational field can be attractive or repulsive depending on the non-canonical kinetic term.
0902.3903
Daniele Oriti
Daniele Oriti
Group field theory and simplicial quantum gravity
14 pages, no figures; RevTex4; v2: definition of the model modified, discussion extended and improved
Class.Quant.Grav.27:145017,2010
10.1088/0264-9381/27/14/145017
ITP-UU-08/58, SPIN-08/45, AEI-2009-022
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a new Group Field Theory for 4d quantum gravity. It incorporates the constraints that give gravity from BF theory, and has quantum amplitudes with the explicit form of simplicial path integrals for 1st order gravity. The geometric interpretation of the variables and of the contributions to the quantum ampl...
[ { "created": "Mon, 23 Feb 2009 13:14:08 GMT", "version": "v1" }, { "created": "Fri, 25 Sep 2009 14:50:09 GMT", "version": "v2" } ]
2014-11-18
[ [ "Oriti", "Daniele", "" ] ]
We present a new Group Field Theory for 4d quantum gravity. It incorporates the constraints that give gravity from BF theory, and has quantum amplitudes with the explicit form of simplicial path integrals for 1st order gravity. The geometric interpretation of the variables and of the contributions to the quantum amplit...
0705.2388
Carlo Rovelli
Jonathan Engle, Roberto Pereira, Carlo Rovelli
The loop-quantum-gravity vertex-amplitude
6pages
Phys.Rev.Lett.99:161301,2007
10.1103/PhysRevLett.99.161301
null
gr-qc
null
Spinfoam theories are hoped to provide the dynamics of non-perturbative loop quantum gravity. But a number of their features remain elusive. The best studied one -the euclidean Barrett-Crane model- does not have the boundary state space needed for this, and there are recent indications that, consequently, it may fail...
[ { "created": "Wed, 16 May 2007 16:03:25 GMT", "version": "v1" } ]
2008-11-26
[ [ "Engle", "Jonathan", "" ], [ "Pereira", "Roberto", "" ], [ "Rovelli", "Carlo", "" ] ]
Spinfoam theories are hoped to provide the dynamics of non-perturbative loop quantum gravity. But a number of their features remain elusive. The best studied one -the euclidean Barrett-Crane model- does not have the boundary state space needed for this, and there are recent indications that, consequently, it may fail t...
2003.04236
Francesco Belgiorno
F. Belgiorno, S.L. Cacciatori and A. Vigan\`o
Analogue Hawking Effect: a master equation
26 pages, 2 figures. Published version. Title a bit changed in PRD
Phys. Rev. D 102, 105003 (2020)
10.1103/PhysRevD.102.105003
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider further on the problem of the analogue Hawking radiation. We propose a fourth order ordinary differential equation, which allows to discuss the problem of Hawking radiation in analogue gravity in a unified way, encompassing fluids and dielectric media. In a suitable approximation, involving weak dispersiv...
[ { "created": "Mon, 9 Mar 2020 16:20:58 GMT", "version": "v1" }, { "created": "Tue, 24 Nov 2020 11:43:09 GMT", "version": "v2" } ]
2020-11-25
[ [ "Belgiorno", "F.", "" ], [ "Cacciatori", "S. L.", "" ], [ "Viganò", "A.", "" ] ]
We consider further on the problem of the analogue Hawking radiation. We propose a fourth order ordinary differential equation, which allows to discuss the problem of Hawking radiation in analogue gravity in a unified way, encompassing fluids and dielectric media. In a suitable approximation, involving weak dispersive ...
gr-qc/0411127
Francois Limousin
Francois Limousin (LUTH), Dorota Gondek-Rosinska (LUTH, CAMK), Eric Gourgoulhon (LUTH)
Last orbits of binary strange quark stars
11 pages, 10 figures, improved conclusion and figures, references added, accepted for publication in Phys. Rev. D
Phys.Rev.D71:064012,2005
10.1103/PhysRevD.71.064012
null
gr-qc astro-ph
null
We present the first relativistic calculations of the final phase of inspiral of a binary system consisting of two stars built predominantely of strange quark matter (strange quark stars). We study the precoalescing stage within the Isenberg-Wilson-Mathews approximation of general relativity using a multidomain spect...
[ { "created": "Fri, 26 Nov 2004 20:15:22 GMT", "version": "v1" }, { "created": "Mon, 21 Mar 2005 10:15:26 GMT", "version": "v2" } ]
2014-11-17
[ [ "Limousin", "Francois", "", "LUTH" ], [ "Gondek-Rosinska", "Dorota", "", "LUTH, CAMK" ], [ "Gourgoulhon", "Eric", "", "LUTH" ] ]
We present the first relativistic calculations of the final phase of inspiral of a binary system consisting of two stars built predominantely of strange quark matter (strange quark stars). We study the precoalescing stage within the Isenberg-Wilson-Mathews approximation of general relativity using a multidomain spectra...
0706.2891
Steven Willison
F. Canfora, A. Giacomini, S. Willison
Some exact solutions with torsion in 5-D Einstein-Gauss-Bonnet gravity
19 pages, LaTex, no figures. References added, notation clarified. Accepted for publication on Physical Review D
Phys.Rev.D76:044021,2007
10.1103/PhysRevD.76.044021
CECS-PHY-07/11
gr-qc hep-th
null
Exact solutions with torsion in Einstein-Gauss-Bonnet gravity are derived. These solutions have a cross product structure of two constant curvature manifolds. The equations of motion give a relation for the coupling constants of the theory in order to have solutions with nontrivial torsion. This relation is not the C...
[ { "created": "Tue, 19 Jun 2007 23:37:33 GMT", "version": "v1" }, { "created": "Tue, 10 Jul 2007 16:06:57 GMT", "version": "v2" } ]
2008-11-26
[ [ "Canfora", "F.", "" ], [ "Giacomini", "A.", "" ], [ "Willison", "S.", "" ] ]
Exact solutions with torsion in Einstein-Gauss-Bonnet gravity are derived. These solutions have a cross product structure of two constant curvature manifolds. The equations of motion give a relation for the coupling constants of the theory in order to have solutions with nontrivial torsion. This relation is not the Che...
gr-qc/0402048
Branchina
Vincenzo Branchina, Alice Gasparini, Anna Rissone
Electronic contribution to the oscillations of a gravitational antenna
25 pages, no figures
Phys.Rev. D70 (2004) 024004
10.1103/PhysRevD.70.024004
null
gr-qc
null
We carefully analyse the contribution to the oscillations of a metallic gravitational antenna due to the interaction between the electrons of the bar and the incoming gravitational wave. To this end, we first derive the total microscopic Hamiltonian of the wave-antenna system and then compute the contribution to the ...
[ { "created": "Wed, 11 Feb 2004 18:46:42 GMT", "version": "v1" } ]
2009-11-10
[ [ "Branchina", "Vincenzo", "" ], [ "Gasparini", "Alice", "" ], [ "Rissone", "Anna", "" ] ]
We carefully analyse the contribution to the oscillations of a metallic gravitational antenna due to the interaction between the electrons of the bar and the incoming gravitational wave. To this end, we first derive the total microscopic Hamiltonian of the wave-antenna system and then compute the contribution to the at...
2403.19942
Jianbo Lu
Jianbo Lu, Shining Yang, Yuying Zhang, Liu Yang, Mou Xu
Research on high-frequency quasi-periodic oscillations in generalized black-bounce spacetime
20 pages, 8 figures
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In order to solve problem of spacetime singularity in theoretical physics, researchers proposed the regular black holes (BH). The generalized black-bounce (GBB) spacetime, as a unified treatment of distinct kinds of geometries in the framework of general relativity (e.g. regular BH and wormholes), has been extensivel...
[ { "created": "Fri, 29 Mar 2024 02:49:34 GMT", "version": "v1" } ]
2024-04-01
[ [ "Lu", "Jianbo", "" ], [ "Yang", "Shining", "" ], [ "Zhang", "Yuying", "" ], [ "Yang", "Liu", "" ], [ "Xu", "Mou", "" ] ]
In order to solve problem of spacetime singularity in theoretical physics, researchers proposed the regular black holes (BH). The generalized black-bounce (GBB) spacetime, as a unified treatment of distinct kinds of geometries in the framework of general relativity (e.g. regular BH and wormholes), has been extensively ...
gr-qc/0504126
Marcelo Salgado
Alejandro Corichi, Ulises Nucamendi, Marcelo Salgado
Scalar hairy black holes and scalarons in the isolated horizons formalism
17 pages, 10 figures; revtex style; figures added; text updated to match the published paper
Phys.Rev.D73:084002,2006
10.1103/PhysRevD.73.084002
null
gr-qc
null
The Isolated Horizons (IH) formalism, together with a simple phenomenological model for colored black holes has been used to predict non-trivial formulae that relate the ADM mass of the solitons and hairy Black Holes of Gravity-Matter system on the one hand, and several horizon properties of the black holes in the ot...
[ { "created": "Tue, 26 Apr 2005 00:54:31 GMT", "version": "v1" }, { "created": "Mon, 7 Aug 2006 23:23:01 GMT", "version": "v2" } ]
2008-11-26
[ [ "Corichi", "Alejandro", "" ], [ "Nucamendi", "Ulises", "" ], [ "Salgado", "Marcelo", "" ] ]
The Isolated Horizons (IH) formalism, together with a simple phenomenological model for colored black holes has been used to predict non-trivial formulae that relate the ADM mass of the solitons and hairy Black Holes of Gravity-Matter system on the one hand, and several horizon properties of the black holes in the othe...
1702.01688
Mehdi Assanioussi
Mehdi Assanioussi, Jerzy Lewandowski, Ilkka M\"akinen
Time evolution in deparametrized models of loop quantum gravity
23 pages, 18 figures
Phys. Rev. D 96, 024043 (2017)
10.1103/PhysRevD.96.024043
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
An important aspect in understanding the dynamics in the context of deparametrized models of LQG is to obtain a sufficient control on the quantum evolution generated by a given Hamiltonian operator. More specifically, we need to be able to compute the evolution of relevant physical states and observables with a relat...
[ { "created": "Mon, 6 Feb 2017 16:26:53 GMT", "version": "v1" } ]
2017-08-02
[ [ "Assanioussi", "Mehdi", "" ], [ "Lewandowski", "Jerzy", "" ], [ "Mäkinen", "Ilkka", "" ] ]
An important aspect in understanding the dynamics in the context of deparametrized models of LQG is to obtain a sufficient control on the quantum evolution generated by a given Hamiltonian operator. More specifically, we need to be able to compute the evolution of relevant physical states and observables with a relativ...
2109.01867
Changqing Liu Lcqliu
Changqing Liu, Li Tang, Jiliang Jing
Image of the Schwarzschild black hole pierced by a cosmic string with a thin accretion disk
null
International Journal of Modern Physics D (2022) 2250041
10.1142/S0218271822500419
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the optical appearance of a thin accretion disk around a Schwarzschild black hole pierced by a cosmic string with a semi-analytic method of Luminet [11]. Direct and secondary images with different parameters observed by a distant observer is plotted. The cosmic string parameter s can modify the shape and siz...
[ { "created": "Sat, 4 Sep 2021 13:47:31 GMT", "version": "v1" }, { "created": "Sun, 12 Sep 2021 12:48:07 GMT", "version": "v2" } ]
2022-04-12
[ [ "Liu", "Changqing", "" ], [ "Tang", "Li", "" ], [ "Jing", "Jiliang", "" ] ]
We study the optical appearance of a thin accretion disk around a Schwarzschild black hole pierced by a cosmic string with a semi-analytic method of Luminet [11]. Direct and secondary images with different parameters observed by a distant observer is plotted. The cosmic string parameter s can modify the shape and size ...
0904.2950
Chen Songbai
Songbai Chen, Jiliang Jing
Dark energy model with higher derivative of Hubble parameter
11 pages, 6 figures, the correct version accepted for publication in PLB
Phys. Lett. B 679 (2009) 144-150
10.1016/j.physletb.2009.07.018
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this letter we consider a dark energy model in which the energy density is a function of the Hubble parameter $H$ and its derivative with respect to time $\rho_{de}=3\alpha \ddot{H}H^{-1}+3\beta\dot{H}+3\gamma H^2$. The behavior of the dark energy and the expansion history of the Universe depend heavily on the par...
[ { "created": "Mon, 20 Apr 2009 06:38:49 GMT", "version": "v1" }, { "created": "Thu, 23 Apr 2009 01:25:53 GMT", "version": "v2" }, { "created": "Tue, 2 Jun 2009 09:02:00 GMT", "version": "v3" }, { "created": "Thu, 16 Jul 2009 03:54:44 GMT", "version": "v4" } ]
2015-05-13
[ [ "Chen", "Songbai", "" ], [ "Jing", "Jiliang", "" ] ]
In this letter we consider a dark energy model in which the energy density is a function of the Hubble parameter $H$ and its derivative with respect to time $\rho_{de}=3\alpha \ddot{H}H^{-1}+3\beta\dot{H}+3\gamma H^2$. The behavior of the dark energy and the expansion history of the Universe depend heavily on the param...
gr-qc/9711003
Robert Mann
H. Burton, R.B. Mann
Palatini Variational Principle for an Extended Einstein-Hilbert Action
14 pages, LaTeX
Phys.Rev. D57 (1998) 4754-4759
10.1103/PhysRevD.57.4754
WATPHYS TH-97/17
gr-qc
null
We consider a Palatini variation on a generalized Einstein-Hilbert action. We find that the Hilbert constraint, that the connection equals the Christoffel symbol, arises only as a special case of this general action, while for particular values of the coefficients of this generalized action, the connection is complet...
[ { "created": "Mon, 3 Nov 1997 18:15:40 GMT", "version": "v1" } ]
2009-10-30
[ [ "Burton", "H.", "" ], [ "Mann", "R. B.", "" ] ]
We consider a Palatini variation on a generalized Einstein-Hilbert action. We find that the Hilbert constraint, that the connection equals the Christoffel symbol, arises only as a special case of this general action, while for particular values of the coefficients of this generalized action, the connection is completel...
gr-qc/9701001
Motoyuki Saijo
Motoyuki Saijo, Hisa-aki Shinkai and Kei-ichi Maeda
Gravitational Waves in Brans-Dicke Theory : Analysis by Test Particles around a Kerr Black Hole
24 pages, revtex, 18 figures are attached with ps files
Phys.Rev. D56 (1997) 785-797
10.1103/PhysRevD.56.785
WU-AP/64/96 (Waseda Univ. Astrophysics)
gr-qc
null
Analyzing test particles falling into a Kerr black hole, we study gravitational waves in Brans-Dicke theory of gravity. First we consider a test particle plunging with a constant azimuthal angle into a rotating black hole and calculate the waveform and emitted energy of both scalar and tensor modes of gravitational r...
[ { "created": "Wed, 1 Jan 1997 03:07:48 GMT", "version": "v1" } ]
2007-05-23
[ [ "Saijo", "Motoyuki", "" ], [ "Shinkai", "Hisa-aki", "" ], [ "Maeda", "Kei-ichi", "" ] ]
Analyzing test particles falling into a Kerr black hole, we study gravitational waves in Brans-Dicke theory of gravity. First we consider a test particle plunging with a constant azimuthal angle into a rotating black hole and calculate the waveform and emitted energy of both scalar and tensor modes of gravitational rad...
gr-qc/0307094
Stephane Fay
Stephane Fay, Jean-Pierre Luminet
Isotropisation of flat homogeneous universes with scalar fields
35 pages, 11 figures, higher-quality images are available on request to steph.fay@wanadoo.fr, to be published in Class. Quant. Grav
Class.Quant.Grav. 21 (2004) 1849-1878
10.1088/0264-9381/21/7/009
null
gr-qc astro-ph
null
Starting from an anisotropic flat cosmological model(Bianchi type $I$), we show that conditions leading to isotropisation fall into 3 classes, respectively 1, 2, 3. We look for necessary conditions such that a Bianchi type $I$ model reaches a stable isotropic state due to the presence of several massive scalar fields...
[ { "created": "Mon, 21 Jul 2003 15:25:04 GMT", "version": "v1" }, { "created": "Tue, 25 Nov 2003 17:36:31 GMT", "version": "v2" }, { "created": "Wed, 18 Feb 2004 12:45:13 GMT", "version": "v3" } ]
2009-11-10
[ [ "Fay", "Stephane", "" ], [ "Luminet", "Jean-Pierre", "" ] ]
Starting from an anisotropic flat cosmological model(Bianchi type $I$), we show that conditions leading to isotropisation fall into 3 classes, respectively 1, 2, 3. We look for necessary conditions such that a Bianchi type $I$ model reaches a stable isotropic state due to the presence of several massive scalar fields m...
gr-qc/9807034
null
Reinoud J. Slagter (University of Amsterdam)
Self-Gravitating Non-Abelian Cosmic String Solution
12 pages in REVTEX with 7 figures in postscript. To appear in PRD nov.'98
Phys.Rev. D59 (1999) 025009
10.1103/PhysRevD.59.025009
null
gr-qc
null
The coupled Einstein-Yang-Mills equations on a time dependent axially symmetric spacetime are investigated, without a priori any conditions on the gauge field. There is numerical evidence for the existence of a regular solution with the desired asymptotic features. Just as in the supermassive abelian counterpart mode...
[ { "created": "Wed, 15 Jul 1998 10:37:14 GMT", "version": "v1" }, { "created": "Tue, 15 Sep 1998 20:44:27 GMT", "version": "v2" } ]
2009-10-31
[ [ "Slagter", "Reinoud J.", "", "University of Amsterdam" ] ]
The coupled Einstein-Yang-Mills equations on a time dependent axially symmetric spacetime are investigated, without a priori any conditions on the gauge field. There is numerical evidence for the existence of a regular solution with the desired asymptotic features. Just as in the supermassive abelian counterpart model,...
1907.12083
Eleonora Giovannetti
Eleonora Giovannetti and Giovanni Montani
Polymer representation of the Bianchi IX Cosmology in the Misner variables
14 pages, 6 figures
Phys. Rev. D 100, 104058 (2019)
10.1103/PhysRevD.100.104058
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We analyze the Bianchi IX Universe in the Polymer Quantum Mechanics framework by facing both semiclassical and purely quantum effects near the cosmological singularity. We adopt Misner variables to describe the model dynamics, applying the polymer paradigm simultaneously to the isotropic one (linked to the Universe v...
[ { "created": "Sun, 28 Jul 2019 14:00:38 GMT", "version": "v1" }, { "created": "Sat, 30 Nov 2019 17:43:59 GMT", "version": "v2" } ]
2019-12-03
[ [ "Giovannetti", "Eleonora", "" ], [ "Montani", "Giovanni", "" ] ]
We analyze the Bianchi IX Universe in the Polymer Quantum Mechanics framework by facing both semiclassical and purely quantum effects near the cosmological singularity. We adopt Misner variables to describe the model dynamics, applying the polymer paradigm simultaneously to the isotropic one (linked to the Universe vol...
2111.03338
Simon Boudet
Flavio Bombacigno, Simon Boudet, Gonzalo J. Olmo, Giovanni Montani
Big-Bounce in projectively invariant Nieh-Yan models: the Bianchi I case
To appear in the Proceedings of the 16th Marcel Grossmann meeting (5-10 July, 2021)
null
null
null
gr-qc
http://creativecommons.org/licenses/by/4.0/
We show that the Nieh-Yan topological invariant breaks projective symmetry and loses its topological character in presence of non vanishing nonmetricity. The notion of the Nieh-Yan topological invariant is then extended to the generic metric-affine case, defining a generalized Nieh-Yan term, which allows to recover t...
[ { "created": "Fri, 5 Nov 2021 09:13:24 GMT", "version": "v1" } ]
2021-11-08
[ [ "Bombacigno", "Flavio", "" ], [ "Boudet", "Simon", "" ], [ "Olmo", "Gonzalo J.", "" ], [ "Montani", "Giovanni", "" ] ]
We show that the Nieh-Yan topological invariant breaks projective symmetry and loses its topological character in presence of non vanishing nonmetricity. The notion of the Nieh-Yan topological invariant is then extended to the generic metric-affine case, defining a generalized Nieh-Yan term, which allows to recover top...
1002.0138
Viqar Husain
Viqar Husain, Andreas Kreienbuehl
Ultraviolet behavior in background independent quantum field theory
8 pages, 5 figures
Phys. Rev. D 81 (2010) 084043
10.1103/PhysRevD.81.084043
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We describe a background independent quantization of the scalar field that provides an explicit realization of Fock-like states and associated operators in a polymer Hilbert space. The vacuum expectation values of the commutator and anti-commutator of the creation and annihilation operators become energy dependent, a...
[ { "created": "Sun, 31 Jan 2010 16:09:12 GMT", "version": "v1" } ]
2015-09-16
[ [ "Husain", "Viqar", "" ], [ "Kreienbuehl", "Andreas", "" ] ]
We describe a background independent quantization of the scalar field that provides an explicit realization of Fock-like states and associated operators in a polymer Hilbert space. The vacuum expectation values of the commutator and anti-commutator of the creation and annihilation operators become energy dependent, and...
1004.0917
Hideki Maeda
Hideki Maeda
Gauss-Bonnet black holes with non-constant curvature horizons
15 pages, 1 figure; v2, discussion clarified and references added; v3, published version; v4, Eqs.(4.22)-(4.24) corrected, which do not change Eqs.(4.25)-(4.27)
Phys.Rev.D81:124007,2010
10.1103/PhysRevD.81.124007
CECS-PHY-10/05
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate static and dynamical n(\ge 6)-dimensional black holes in Einstein-Gauss-Bonnet gravity of which horizons have the isometries of an (n-2)-dimensional Einstein space with a condition on its Weyl tensor originally given by Dotti and Gleiser. Defining a generalized Misner-Sharp quasi-local mass that satisf...
[ { "created": "Tue, 6 Apr 2010 18:14:29 GMT", "version": "v1" }, { "created": "Wed, 14 Apr 2010 18:37:48 GMT", "version": "v2" }, { "created": "Thu, 3 Jun 2010 00:17:05 GMT", "version": "v3" }, { "created": "Thu, 23 Dec 2010 22:56:50 GMT", "version": "v4" } ]
2010-12-27
[ [ "Maeda", "Hideki", "" ] ]
We investigate static and dynamical n(\ge 6)-dimensional black holes in Einstein-Gauss-Bonnet gravity of which horizons have the isometries of an (n-2)-dimensional Einstein space with a condition on its Weyl tensor originally given by Dotti and Gleiser. Defining a generalized Misner-Sharp quasi-local mass that satisfie...
2311.03860
Bill Atkins
Bill Atkins, Gianmassimo Tasinato
Hidden conformal symmetries for black holes in modified gravity
22 pages, no figures
null
10.1103/PhysRevD.108.104070
null
gr-qc hep-th
http://creativecommons.org/licenses/by/4.0/
We determine hidden conformal symmetries behind the evolution equations of black hole perturbations in a vector-tensor theory of gravity. Such hidden symmetries are valid everywhere in the exterior region of a spherically symmetric, asymptotically flat black hole geometry. They allow us to factorize second order oper...
[ { "created": "Tue, 7 Nov 2023 10:21:49 GMT", "version": "v1" } ]
2023-12-04
[ [ "Atkins", "Bill", "" ], [ "Tasinato", "Gianmassimo", "" ] ]
We determine hidden conformal symmetries behind the evolution equations of black hole perturbations in a vector-tensor theory of gravity. Such hidden symmetries are valid everywhere in the exterior region of a spherically symmetric, asymptotically flat black hole geometry. They allow us to factorize second order operat...
gr-qc/0211091
Ettore Minguzzi
E. Minguzzi and A. Macdonald
Universal one-way light speed from a universal light speed over closed paths
RevTex4, 6 pages, 2 figures, uses psfrag. New sections added, discussion expanded
Found.Phys.Lett. 16 (2003) 593-604
10.1023/B:FOPL.0000012785.16203.52
null
gr-qc physics.ed-ph
null
This paper gives two complete and elementary proofs that if the speed of light over closed paths has a universal value $c$, then it is possible to synchronize clocks in such a way that the one-way speed of light is c. The first proof is an elementary version of a recent proof. The second provides high precision exper...
[ { "created": "Wed, 27 Nov 2002 10:03:11 GMT", "version": "v1" }, { "created": "Wed, 11 Dec 2002 14:21:18 GMT", "version": "v2" }, { "created": "Wed, 1 Oct 2003 11:38:27 GMT", "version": "v3" } ]
2007-05-23
[ [ "Minguzzi", "E.", "" ], [ "Macdonald", "A.", "" ] ]
This paper gives two complete and elementary proofs that if the speed of light over closed paths has a universal value $c$, then it is possible to synchronize clocks in such a way that the one-way speed of light is c. The first proof is an elementary version of a recent proof. The second provides high precision experim...
1504.04844
Guillermo Andree Oliva-Mercado
Guillermo Andree Oliva-Mercado, Javier Bonatti-Gonz\'alez, Iv\'an Cordero-Garc\'ia, Francisco Frutos-Alfaro
A Visualization of Null Geodesics for the Bonnor Massive Dipole
9 pages, 5 figures, Presented at XIX Simposio Internacional de M\'etodos Matem\'aticos Aplicados a las Ciencias (19th International Symposium of Mathematical Methods Applied to Sciences, XIX-SIMMAC)
Revista de Matem\'atica: Teor\'ia y Aplicaciones 2015 22(2) 255-264
10.15517/rmta.v22i2.20723
null
gr-qc math.DG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this work we simulate null geodesics for the Bonnor massive dipole metric by implementing a symbolic-numerical algorithm in Sage and Python. This program is also capable of visualizing in 3D, in principle, the geodesics for any given metric. Geodesics are launched from a common point, collectively forming a cone o...
[ { "created": "Sun, 19 Apr 2015 16:11:21 GMT", "version": "v1" } ]
2015-10-20
[ [ "Oliva-Mercado", "Guillermo Andree", "" ], [ "Bonatti-González", "Javier", "" ], [ "Cordero-García", "Iván", "" ], [ "Frutos-Alfaro", "Francisco", "" ] ]
In this work we simulate null geodesics for the Bonnor massive dipole metric by implementing a symbolic-numerical algorithm in Sage and Python. This program is also capable of visualizing in 3D, in principle, the geodesics for any given metric. Geodesics are launched from a common point, collectively forming a cone of ...
0905.2263
Roman Sverdlov
Roman Sverdlov
Ph.D. Thesis: Quantum Field Theory and Gravity in Causal Sets
211 pages, no figures
R. Sverdlov; Quantum Field Theory and Gravity in Causal Sets; PhD Thesis (University of Michigan 2009)
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This is is a copy of dissertation that I have submitted in defense of my ph.d. thesis, with some minor changes that I have made since then. The goal of the project is to generalize matter fields and their Lagrangians from regular space time to causal sets.
[ { "created": "Thu, 14 May 2009 07:09:42 GMT", "version": "v1" } ]
2012-06-15
[ [ "Sverdlov", "Roman", "" ] ]
This is is a copy of dissertation that I have submitted in defense of my ph.d. thesis, with some minor changes that I have made since then. The goal of the project is to generalize matter fields and their Lagrangians from regular space time to causal sets.
1812.01076
Cemsinan Deliduman
Oguzhan Kasikci and Cemsinan Deliduman
Gravitational Lensing in Weyl Gravity
14 pages; v2: published version
Phys. Rev. D 100, 024019 (2019)
10.1103/PhysRevD.100.024019
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We calculate the deflection angle of light from a distant source by a galaxy cluster in Weyl's conformal gravity. The general method of calculation is first applied to calculate the deflection angle in Schwarzschild-de Sitter (Kottler) spacetime. The deflection angle calculated in Kottler spacetime includes the contr...
[ { "created": "Mon, 3 Dec 2018 20:44:46 GMT", "version": "v1" }, { "created": "Thu, 17 Oct 2019 15:25:52 GMT", "version": "v2" } ]
2019-10-18
[ [ "Kasikci", "Oguzhan", "" ], [ "Deliduman", "Cemsinan", "" ] ]
We calculate the deflection angle of light from a distant source by a galaxy cluster in Weyl's conformal gravity. The general method of calculation is first applied to calculate the deflection angle in Schwarzschild-de Sitter (Kottler) spacetime. The deflection angle calculated in Kottler spacetime includes the contrib...
2403.13052
Jorge Castelo Mourelle
Jorge Castelo Mourelle, Christoph Adam, Juan Calder\'on Bustillo, Nicolas Sanchis-Gual
Rotating Fermion-Boson Stars
19 pages, 8 figures. We have added the treatment of static solutions, improved some discussions about the results, and corrected various typos
null
null
null
gr-qc
http://creativecommons.org/licenses/by/4.0/
Rotating fermion-boson stars are hypothetical celestial objects that consist of both fermionic and bosonic matter interacting exclusively through gravity. Bosonic fields are believed to arise in certain models of particle physics describing dark matter and could accumulate within neutron stars, modifying some of thei...
[ { "created": "Tue, 19 Mar 2024 18:00:02 GMT", "version": "v1" }, { "created": "Wed, 27 Mar 2024 10:43:16 GMT", "version": "v2" }, { "created": "Mon, 1 Apr 2024 13:14:22 GMT", "version": "v3" }, { "created": "Tue, 18 Jun 2024 14:17:42 GMT", "version": "v4" } ]
2024-06-19
[ [ "Mourelle", "Jorge Castelo", "" ], [ "Adam", "Christoph", "" ], [ "Bustillo", "Juan Calderón", "" ], [ "Sanchis-Gual", "Nicolas", "" ] ]
Rotating fermion-boson stars are hypothetical celestial objects that consist of both fermionic and bosonic matter interacting exclusively through gravity. Bosonic fields are believed to arise in certain models of particle physics describing dark matter and could accumulate within neutron stars, modifying some of their ...
1306.1943
Mehrdad Farhoudi Prof.
Amir F. Bahrehbakhsh, Mehrdad Farhoudi, Hajar Vakili
Dark Energy From Fifth Dimensional Brans-Dicke Theory
16 pages, 5 figures, 3 tables
Inter. J. Mod. Phys. D Vol. 22, No. 12 (2013) 1350070 (18 pages)
10.1142/S0218271813500703
null
gr-qc astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Following the approach of the induced-matter theory, we investigate the cosmological implications of a five-dimensional Brans-Dicke theory, and propose to explain the acceleration of the universe. After inducing in a four-dimensional hypersurface, we classify the energy-momentum tensor into two parts in a way that, o...
[ { "created": "Sat, 8 Jun 2013 16:58:32 GMT", "version": "v1" }, { "created": "Tue, 9 Jul 2013 14:04:54 GMT", "version": "v2" } ]
2013-07-10
[ [ "Bahrehbakhsh", "Amir F.", "" ], [ "Farhoudi", "Mehrdad", "" ], [ "Vakili", "Hajar", "" ] ]
Following the approach of the induced-matter theory, we investigate the cosmological implications of a five-dimensional Brans-Dicke theory, and propose to explain the acceleration of the universe. After inducing in a four-dimensional hypersurface, we classify the energy-momentum tensor into two parts in a way that, one...
gr-qc/0506014
Joel Franklin
S. Deser and J. Franklin
Birkhoff for Lovelock Redux
Submitted to CQG
Class.Quant.Grav.22:L103-L106,2005
10.1088/0264-9381/22/16/L03
null
gr-qc hep-th
null
We show succinctly that all metric theories with second order field equations obey Birkhoff's theorem: their spherically symmetric solutions are static.
[ { "created": "Thu, 2 Jun 2005 19:54:32 GMT", "version": "v1" } ]
2010-11-05
[ [ "Deser", "S.", "" ], [ "Franklin", "J.", "" ] ]
We show succinctly that all metric theories with second order field equations obey Birkhoff's theorem: their spherically symmetric solutions are static.
1302.1016
Daniel Kennefick
Shasvath J. Kapadia, Daniel Kennefick and Kostas Glampedakis
Do floating orbits in extreme mass ratio binary black holes exist?
11 pages, 7 Figures
null
10.1103/PhysRevD.87.044050
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper examines the possibility of floating or non-decaying orbits for extreme mass ratio binary black holes. In the adiabatic approximation, valid in the extreme mass ratio case, if the orbital flux lost due to gravitational radiation reaction is compensated for by the orbital flux gained from the spins of the b...
[ { "created": "Tue, 5 Feb 2013 12:51:41 GMT", "version": "v1" } ]
2015-06-12
[ [ "Kapadia", "Shasvath J.", "" ], [ "Kennefick", "Daniel", "" ], [ "Glampedakis", "Kostas", "" ] ]
This paper examines the possibility of floating or non-decaying orbits for extreme mass ratio binary black holes. In the adiabatic approximation, valid in the extreme mass ratio case, if the orbital flux lost due to gravitational radiation reaction is compensated for by the orbital flux gained from the spins of the bla...
1910.09980
Farhad Darabi
H. Hadi, Y. Heydarzade, F. Darabi and K. Atazadeh
D-bound and Bekenstein bound for McVittie solution surrounded by dark energy cosmological fields
13 pages, Minor revision
Eur. Phys. J. Plus, 135:584, (2020)
10.1140/epjp/s13360-020-00601-7
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The cosmological candidate fields for dark energy as quintessence, phantom and cosmological constant, are studied in terms of an entropic hypothesis imposed on the McVittie solution surrounded by dark energy. We certify this hypothesis as "$D$-bound-Bekenstein bound identification" for dilute systems and use it as a ...
[ { "created": "Mon, 21 Oct 2019 09:44:53 GMT", "version": "v1" }, { "created": "Tue, 15 Dec 2020 16:04:01 GMT", "version": "v2" } ]
2020-12-16
[ [ "Hadi", "H.", "" ], [ "Heydarzade", "Y.", "" ], [ "Darabi", "F.", "" ], [ "Atazadeh", "K.", "" ] ]
The cosmological candidate fields for dark energy as quintessence, phantom and cosmological constant, are studied in terms of an entropic hypothesis imposed on the McVittie solution surrounded by dark energy. We certify this hypothesis as "$D$-bound-Bekenstein bound identification" for dilute systems and use it as a cr...
1409.4854
Masashi Kuniyasu
Masashi Kuniyasu
New Solutions of the $2+1$ Dimensional Einstein Gravity Coupled to Maxwell Power type Non Linear Electric field with Dilaton field
6 pages, 3 figures
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
New solutions are derived in the $2+1$ gravity which is coupled to $|{\cal F}|^k$ type non-linear electric field in Maxwell Power theory with dilaton field. We obtain consistent solutions in general $k$ case. We also investigate the behavior of the metric function with the space-time singularity. Then, we found some ...
[ { "created": "Wed, 17 Sep 2014 02:22:56 GMT", "version": "v1" }, { "created": "Fri, 7 Nov 2014 08:43:21 GMT", "version": "v2" }, { "created": "Wed, 12 Nov 2014 05:49:35 GMT", "version": "v3" }, { "created": "Tue, 27 Jan 2015 07:12:17 GMT", "version": "v4" } ]
2015-01-28
[ [ "Kuniyasu", "Masashi", "" ] ]
New solutions are derived in the $2+1$ gravity which is coupled to $|{\cal F}|^k$ type non-linear electric field in Maxwell Power theory with dilaton field. We obtain consistent solutions in general $k$ case. We also investigate the behavior of the metric function with the space-time singularity. Then, we found some bl...
1511.00388
Kartik Prabhu
Kartik Prabhu
The First Law of Black Hole Mechanics for Fields with Internal Gauge Freedom
v4: 69 pages, shorter, less pedagogical version, updated references (published in CQG). v3: minor typographic corrections (PhD thesis version). v2: 80 pages, 1 figure, significant changes to presentation and text; added Thm 1 and Thm2. v1: 64 pages, 1 figure
Class. Quantum Grav. 34 035011, 2017
10.1088/1361-6382/aa536b
null
gr-qc hep-th math-ph math.MP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We derive the first law of black hole mechanics for physical theories based on a local, covariant and gauge-invariant Lagrangian where the dynamical fields transform non-trivially under the action of internal gauge transformations. The theories of interest include General Relativity formulated in terms of tetrads, Ei...
[ { "created": "Mon, 2 Nov 2015 05:50:42 GMT", "version": "v1" }, { "created": "Thu, 16 Jun 2016 21:22:14 GMT", "version": "v2" }, { "created": "Tue, 13 Dec 2016 20:46:29 GMT", "version": "v3" }, { "created": "Tue, 10 Jan 2017 20:47:21 GMT", "version": "v4" } ]
2017-01-12
[ [ "Prabhu", "Kartik", "" ] ]
We derive the first law of black hole mechanics for physical theories based on a local, covariant and gauge-invariant Lagrangian where the dynamical fields transform non-trivially under the action of internal gauge transformations. The theories of interest include General Relativity formulated in terms of tetrads, Eins...
gr-qc/0405054
Yasuo Ezawa
Y.Ezawa, H.Iwasaki, Y.Ohkuwa, T.Uegaki, N.Yamada and T.Yano
Interpretation of the first order formalism of f(R)-type gravity and the corresponding second order formalism
7 pages, extended and revised version of gr-qc/0309010
Nuovo Cim.B119:1141-1148,2004
10.1393/ncb/i2004-10127-5
null
gr-qc
null
f(R)-type gravity in the first order formalism is interpreted as Einstein gravity with non-minimal coupling arising from the use of unphysical frame. Identification of the corresponding second order higher-curvature gravity in the physical frame is proposed by requiring that the action is the same.
[ { "created": "Tue, 11 May 2004 11:53:34 GMT", "version": "v1" } ]
2010-11-11
[ [ "Ezawa", "Y.", "" ], [ "Iwasaki", "H.", "" ], [ "Ohkuwa", "Y.", "" ], [ "Uegaki", "T.", "" ], [ "Yamada", "N.", "" ], [ "Yano", "T.", "" ] ]
f(R)-type gravity in the first order formalism is interpreted as Einstein gravity with non-minimal coupling arising from the use of unphysical frame. Identification of the corresponding second order higher-curvature gravity in the physical frame is proposed by requiring that the action is the same.
1006.5118
Vladimir S. Manko
F.J. Ernst, V.S. Manko and E. Ruiz
On interrelations between Sibgatullin's and Alekseev's approaches to the construction of exact solutions of the Einstein-Maxwell equations
7 pages, no figures, section II extended
J.Phys.Conf.Ser.229:012050,2010
10.1088/1742-6596/229/1/012050
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The integral equations involved in Alekseev's "monodromy transform" technique are shown to be simple combinations of Sibgatullin's integral equations and normalizing conditions. An additional complex conjugation introduced by Alekseev in the integrands makes his scheme mathematically inconsistent; besides, in the ele...
[ { "created": "Sat, 26 Jun 2010 08:00:03 GMT", "version": "v1" } ]
2010-12-17
[ [ "Ernst", "F. J.", "" ], [ "Manko", "V. S.", "" ], [ "Ruiz", "E.", "" ] ]
The integral equations involved in Alekseev's "monodromy transform" technique are shown to be simple combinations of Sibgatullin's integral equations and normalizing conditions. An additional complex conjugation introduced by Alekseev in the integrands makes his scheme mathematically inconsistent; besides, in the elect...
gr-qc/0603087
Domenico Giulini
Domenico Giulini
Some remarks on the notions of general covariance and background independence
26 pages, 3 figures. Contribution to ``An assessment of current paradigms in the physics of fundamental interactions'', edited by I.O. Stamatescu (Springer Verlag, to appear)
Lect.NotesPhys.721:105-120,2007
10.1007/978-3-540-71117-9_6
Freiburg THEP-06/04
gr-qc
null
In the first part of this paper I review some of the difficulties that seem to obstruct generally valid definitions of "general covariance" and/or "background independence" The second and more historical part deals with a rather strange argument that Einstein put forward in his 1913 "Entwurf paper" with M. Grossmann ...
[ { "created": "Wed, 22 Mar 2006 14:59:24 GMT", "version": "v1" } ]
2008-11-26
[ [ "Giulini", "Domenico", "" ] ]
In the first part of this paper I review some of the difficulties that seem to obstruct generally valid definitions of "general covariance" and/or "background independence" The second and more historical part deals with a rather strange argument that Einstein put forward in his 1913 "Entwurf paper" with M. Grossmann to...
gr-qc/9505026
Jorma Louko
Jorma Louko
Witten's 2+1 gravity on R x (Klein bottle)
33 pages, REVTeX v3.0, 3 figures in a separate PostScript file
Class.Quant.Grav. 12 (1995) 2441-2468
10.1088/0264-9381/12/10/006
WISC--MILW--95--TH--15
gr-qc hep-th
null
Witten's formulation of 2+1 gravity is investigated on the nonorientable three-manifold R x (Klein bottle). The gauge group is taken to consist of all four components of the 2+1 Poincare group. We analyze in detail several components of the classical solution space, and we show that from four of the components one ca...
[ { "created": "Wed, 17 May 1995 00:09:02 GMT", "version": "v1" } ]
2009-10-28
[ [ "Louko", "Jorma", "" ] ]
Witten's formulation of 2+1 gravity is investigated on the nonorientable three-manifold R x (Klein bottle). The gauge group is taken to consist of all four components of the 2+1 Poincare group. We analyze in detail several components of the classical solution space, and we show that from four of the components one can ...
2203.11215
Olivier Minazzoli
Olivier Minazzoli
On the shortcomings of the Shapiro delay tests of the equivalence principle
2 pages. Contribution to the 2022 Gravitation session of the 56th Rencontres de Moriond
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
There are several shortcomings in the "standard" Shapiro delay tests of the equivalence principle on cosmological scales \cite{minazzoli:2019pr}. Although many people in the community already acknowledged this in the literature, and proposed alternative ways to compare potential Shapiro delays over cosmological scale...
[ { "created": "Mon, 21 Mar 2022 16:54:40 GMT", "version": "v1" } ]
2022-03-23
[ [ "Minazzoli", "Olivier", "" ] ]
There are several shortcomings in the "standard" Shapiro delay tests of the equivalence principle on cosmological scales \cite{minazzoli:2019pr}. Although many people in the community already acknowledged this in the literature, and proposed alternative ways to compare potential Shapiro delays over cosmological scales ...
1602.02552
Deng Wang
Guang Yang, Deng Wang, and Xinhe Meng
Diagnostics and future evolution analysis of the two parametric models
null
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we apply three diagnostics including $Om$, Statefinder hierarchy and the growth rate of perturbations into discriminating the two parametric models for the effective pressure with the $\Lambda$CDM model. By using the $Om$ diagnostic, we find that both the model 1 and the model 2 can be hardly distingui...
[ { "created": "Mon, 8 Feb 2016 13:12:35 GMT", "version": "v1" } ]
2016-02-09
[ [ "Yang", "Guang", "" ], [ "Wang", "Deng", "" ], [ "Meng", "Xinhe", "" ] ]
In this paper, we apply three diagnostics including $Om$, Statefinder hierarchy and the growth rate of perturbations into discriminating the two parametric models for the effective pressure with the $\Lambda$CDM model. By using the $Om$ diagnostic, we find that both the model 1 and the model 2 can be hardly distinguish...
1607.06695
Mahsa Sanati
Fatimah Shojai, Mahsa Sanati
Investigation of energy conditions in the vicinity of future cosmological singularities
I withdraw this paper since my former supervisor require me to withdraw this paper
null
null
null
gr-qc astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, considering the energy conditions we shall show that some of the energy conditions are violated in the vicinity of future singularities with the scale factor suggested by Dabrowski - Marosek.
[ { "created": "Thu, 21 Jul 2016 07:44:29 GMT", "version": "v1" }, { "created": "Tue, 26 Jul 2016 18:27:29 GMT", "version": "v2" } ]
2016-07-27
[ [ "Shojai", "Fatimah", "" ], [ "Sanati", "Mahsa", "" ] ]
In this paper, considering the energy conditions we shall show that some of the energy conditions are violated in the vicinity of future singularities with the scale factor suggested by Dabrowski - Marosek.
2008.02137
Viktor T. Toth
J. W. Moffat and V. T. Toth
Applying Modified Gravity (MOG) to the Lensing and Einstein Ring in Abell 3827
4 pages, 1 figure. Minor corrections. arXiv admin note: substantial text overlap with arXiv:2006.12550
Phys. Rev. D 103, 044045 (2021)
10.1103/PhysRevD.103.044045
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The lensing and Einstein ring at the core of the galaxy cluster Abell 3827 are reproduced in the modified gravity theory MOG. The estimated effective lensing mass $M_L=(1+\alpha)M_b=5.2\times 10^{12} M_\odot$ within $R=18.3$~kpc for a baryon mass $M_b=1.0\times 10^{12} M_\odot$ within the same radius produces the obs...
[ { "created": "Tue, 4 Aug 2020 15:38:15 GMT", "version": "v1" }, { "created": "Fri, 14 Aug 2020 15:40:07 GMT", "version": "v2" } ]
2021-02-24
[ [ "Moffat", "J. W.", "" ], [ "Toth", "V. T.", "" ] ]
The lensing and Einstein ring at the core of the galaxy cluster Abell 3827 are reproduced in the modified gravity theory MOG. The estimated effective lensing mass $M_L=(1+\alpha)M_b=5.2\times 10^{12} M_\odot$ within $R=18.3$~kpc for a baryon mass $M_b=1.0\times 10^{12} M_\odot$ within the same radius produces the obser...
0911.2450
Anil Zenginoglu C
Anil Zenginoglu
Asymptotics of Schwarzschild black hole perturbations
9 pages, 8 figures; changed title, updated references, matches the published version
Class.Quant.Grav.27:045015,2010
10.1088/0264-9381/27/4/045015
CSCAMM-09-21
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study linear gravitational perturbations of Schwarzschild spacetime by solving numerically Regge-Wheeler-Zerilli equations in time domain using hyperboloidal surfaces and a compactifying radial coordinate. We stress the importance of including the asymptotic region in the computational domain in studies of gravita...
[ { "created": "Thu, 12 Nov 2009 19:16:45 GMT", "version": "v1" }, { "created": "Tue, 2 Feb 2010 03:09:47 GMT", "version": "v2" } ]
2010-03-26
[ [ "Zenginoglu", "Anil", "" ] ]
We study linear gravitational perturbations of Schwarzschild spacetime by solving numerically Regge-Wheeler-Zerilli equations in time domain using hyperboloidal surfaces and a compactifying radial coordinate. We stress the importance of including the asymptotic region in the computational domain in studies of gravitati...
gr-qc/0203025
Guillermo A. Mena Marugan
Saulo Carneiro and Guillermo A. Mena Marugan
An anisotropic cosmological model with isotropic background radiation
4 pages; contribution to the Proceedings of the 24th Spanish Relativity Meeting (ERE2001)
Lect.Notes Phys. 617 (2003) 302
10.1007/3-540-36973-2_17
null
gr-qc astro-ph
null
We present an exact solution of Einstein equations that describes a Bianchi type III spacetime with conformal expansion. The matter content is given by an anisotropic scalar field and two perfect fluids representing dust and isotropic radiation. Based on this solution, we construct a cosmological model that respects ...
[ { "created": "Thu, 7 Mar 2002 17:51:00 GMT", "version": "v1" } ]
2013-11-11
[ [ "Carneiro", "Saulo", "" ], [ "Marugan", "Guillermo A. Mena", "" ] ]
We present an exact solution of Einstein equations that describes a Bianchi type III spacetime with conformal expansion. The matter content is given by an anisotropic scalar field and two perfect fluids representing dust and isotropic radiation. Based on this solution, we construct a cosmological model that respects th...
gr-qc/9508052
Larry Shepley
J M Pons (Univ Barcelona) & L C Shepley (Univ Texas Austin)
Evolutionary Laws, Initial Conditions, and Gauge Fixing in Constrained Systems
23 pages; plain TeX. To appear: Classical & Quantum Gravity
Class.Quant.Grav.12:1771-1790,1995
10.1088/0264-9381/12/7/018
null
gr-qc
null
We describe in detail how to eliminate nonphysical degrees of freedom in the Lagrangian and Hamiltonian formulations of a constrained system. Two important and distinct steps in our method are the fixing of ambiguities in the dynamics and the determination of inequivalent initial data. The Lagrangian discussion is no...
[ { "created": "Fri, 25 Aug 1995 16:35:32 GMT", "version": "v1" } ]
2010-04-06
[ [ "Pons", "J M", "", "Univ Barcelona" ], [ "Shepley", "L C", "", "Univ Texas Austin" ] ]
We describe in detail how to eliminate nonphysical degrees of freedom in the Lagrangian and Hamiltonian formulations of a constrained system. Two important and distinct steps in our method are the fixing of ambiguities in the dynamics and the determination of inequivalent initial data. The Lagrangian discussion is nove...
gr-qc/9312004
null
G. L. Rcheulishvili
Conformal Killing Vectors in Five-Dimensional Space
9 pages, LaTeX file, IHEP 93-121
null
null
null
gr-qc
null
The solutions of generalized Killing equation have been obtained for line element with initial $t^2 \oplus so(3)$ symmetry. The coefficients of the metric $g$ corresponding to these vector fields are written down.
[ { "created": "Thu, 2 Dec 1993 13:26:26 GMT", "version": "v1" } ]
2007-05-23
[ [ "Rcheulishvili", "G. L.", "" ] ]
The solutions of generalized Killing equation have been obtained for line element with initial $t^2 \oplus so(3)$ symmetry. The coefficients of the metric $g$ corresponding to these vector fields are written down.
gr-qc/0002060
Jose Wadih Maluf
J. W. Maluf and A. A. Sousa
Hamiltonian formulation of teleparallel theories of gravity in the time gauge
22 pages, Latex file, no figures
null
null
null
gr-qc
null
We consider the most general class of teleparallel theories of gravity quadratic in the torsion tensor, and carry out a detailed investigation of its Hamiltonian formulation in the time gauge. Such general class is given by a three-parameter family of theories. A consistent implementation of the Legendre transform re...
[ { "created": "Wed, 16 Feb 2000 22:17:26 GMT", "version": "v1" } ]
2007-05-23
[ [ "Maluf", "J. W.", "" ], [ "Sousa", "A. A.", "" ] ]
We consider the most general class of teleparallel theories of gravity quadratic in the torsion tensor, and carry out a detailed investigation of its Hamiltonian formulation in the time gauge. Such general class is given by a three-parameter family of theories. A consistent implementation of the Legendre transform redu...
0706.2905
Myungseok Yoon
Chang-Young Ee, Daeho Lee, and Myungseok Yoon
Entropy of Schwarzschild Black Holes on DGP Brane
6 pages, 1 figure; to appear in J. Kor. Phys. Soc
J.Korean Phys.Soc. 51 (2007) 2091-2093
null
null
gr-qc
null
We study the entropy of Schwarzschild black holes on DGP brane. The radius of event horizon on DGP brane is obtained by a numerical method. It is smaller than that of Einstein gravity in the conventional branch, and is larger in the accelerated branch. However, the difference is very small. The entropy of the black h...
[ { "created": "Wed, 20 Jun 2007 03:29:54 GMT", "version": "v1" }, { "created": "Fri, 2 Nov 2007 05:32:31 GMT", "version": "v2" } ]
2008-10-21
[ [ "Ee", "Chang-Young", "" ], [ "Lee", "Daeho", "" ], [ "Yoon", "Myungseok", "" ] ]
We study the entropy of Schwarzschild black holes on DGP brane. The radius of event horizon on DGP brane is obtained by a numerical method. It is smaller than that of Einstein gravity in the conventional branch, and is larger in the accelerated branch. However, the difference is very small. The entropy of the black hol...
gr-qc/9904012
Gravity Research Group
Alexander Burinskii and Giulio Magli
Kerr-Schild Approach to the Boosted Kerr Solution
16 pages, LaTeX
Phys.Rev. D61 (2000) 044017
10.1103/PhysRevD.61.044017
null
gr-qc hep-th
null
Using a complex representation of the Debney-Kerr-Schild (DKS) solutions and the Kerr theorem we analyze the boosted Kerr geometries and give the exact and explicit expressions for the metrics, the principal null congruences, the coordinate systems and the location of the singularities for arbitrary value and orienta...
[ { "created": "Tue, 6 Apr 1999 13:33:26 GMT", "version": "v1" } ]
2009-10-31
[ [ "Burinskii", "Alexander", "" ], [ "Magli", "Giulio", "" ] ]
Using a complex representation of the Debney-Kerr-Schild (DKS) solutions and the Kerr theorem we analyze the boosted Kerr geometries and give the exact and explicit expressions for the metrics, the principal null congruences, the coordinate systems and the location of the singularities for arbitrary value and orientati...
1002.0524
Panagiotis Kordas Dr
Panagiotis Kordas
Transition Matrix, Poisson Bracket for gravitational solitons in the dressing formalism
9 pages, Comments welcome, results explicitly expressed in Introduction and abstract
null
null
null
gr-qc hep-th nlin.SI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Hamiltonian methods of the theory of solitons are applied to gravisolitons in the dressing formalism. The Poisson bracket for the Lie-algebra valued one-form $A(\varsigma, \eta, \gamma)=\Psi_{,\gamma}\Psi^{-1}$, for gravisolitons in the dressing formalism, for a specific background solution, is defined and comput...
[ { "created": "Tue, 2 Feb 2010 16:24:42 GMT", "version": "v1" }, { "created": "Wed, 15 Dec 2010 11:09:20 GMT", "version": "v2" }, { "created": "Fri, 28 Jan 2011 18:15:01 GMT", "version": "v3" } ]
2011-01-31
[ [ "Kordas", "Panagiotis", "" ] ]
The Hamiltonian methods of the theory of solitons are applied to gravisolitons in the dressing formalism. The Poisson bracket for the Lie-algebra valued one-form $A(\varsigma, \eta, \gamma)=\Psi_{,\gamma}\Psi^{-1}$, for gravisolitons in the dressing formalism, for a specific background solution, is defined and computed...
1410.6065
Andrew Scacco
Daniel Phillips, Andrew Scacco, and Andreas Albrecht
Holographic bounds and finite inflation
14 pages, 10 figures
Phys. Rev. D 91, 043513 (2015)
10.1103/PhysRevD.91.043513
null
gr-qc astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We compare two holographic arguments that impose especially strong bounds on the amount of inflation. One comes from the de Sitter Equilibrium cosmology and the other from the work of Banks and Fischler. We find that simple versions of these two approaches yield the same bound on the number of e-foldings. A careful e...
[ { "created": "Mon, 13 Oct 2014 22:02:45 GMT", "version": "v1" } ]
2015-03-05
[ [ "Phillips", "Daniel", "" ], [ "Scacco", "Andrew", "" ], [ "Albrecht", "Andreas", "" ] ]
We compare two holographic arguments that impose especially strong bounds on the amount of inflation. One comes from the de Sitter Equilibrium cosmology and the other from the work of Banks and Fischler. We find that simple versions of these two approaches yield the same bound on the number of e-foldings. A careful exa...
1203.5709
T.G Zlosnik
H. F. Westman and T. G. Zlosnik
Gravity, Cartan geometry, and idealized waywisers
Some typos corrected and presentation cleaned up in places. Much of the content of this paper may also be found in the larger and more recent paper arXiv:1411.1679
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The primary aim of this paper is to provide a simple and concrete interpretation of Cartan geometry in terms of the mathematics of idealized waywisers. Waywisers, also called hodometers, are instruments traditionally used to measure distances. The mathematical representation of an idealized waywiser consists of a cho...
[ { "created": "Mon, 26 Mar 2012 16:04:35 GMT", "version": "v1" }, { "created": "Tue, 27 Mar 2012 17:13:24 GMT", "version": "v2" }, { "created": "Thu, 12 Apr 2012 21:08:08 GMT", "version": "v3" }, { "created": "Mon, 16 Feb 2015 14:57:35 GMT", "version": "v4" } ]
2015-02-17
[ [ "Westman", "H. F.", "" ], [ "Zlosnik", "T. G.", "" ] ]
The primary aim of this paper is to provide a simple and concrete interpretation of Cartan geometry in terms of the mathematics of idealized waywisers. Waywisers, also called hodometers, are instruments traditionally used to measure distances. The mathematical representation of an idealized waywiser consists of a choic...
gr-qc/0602076
Stefan Nobbenhuis
Gerard 't Hooft and Stefan Nobbenhuis
Invariance under complex transformations, and its relevance to the cosmological constant problem
Some clarifications and references added
Class.Quant.Grav.23:3819-3832,2006
10.1088/0264-9381/23/11/009
ITP-UU-06/06, SPIN-06/04
gr-qc hep-th
null
In this paper we study a new symmetry argument that results in a vacuum state with strictly vanishing vacuum energy. This argument exploits the well-known feature that de Sitter and Anti- de Sitter space are related by analytic continuation. When we drop boundary and hermiticity conditions on quantum fields, we get a...
[ { "created": "Mon, 20 Feb 2006 16:15:48 GMT", "version": "v1" }, { "created": "Tue, 4 Apr 2006 13:34:07 GMT", "version": "v2" } ]
2009-11-11
[ [ "Hooft", "Gerard 't", "" ], [ "Nobbenhuis", "Stefan", "" ] ]
In this paper we study a new symmetry argument that results in a vacuum state with strictly vanishing vacuum energy. This argument exploits the well-known feature that de Sitter and Anti- de Sitter space are related by analytic continuation. When we drop boundary and hermiticity conditions on quantum fields, we get as ...
gr-qc/9806109
Kourosh Nozari
Reza Mansouri and Kourosh Nozari
Signature Change, Inflation, and the Cosmological Constant
15 pages, Latex, no figures
null
null
IPM/P - 98/15
gr-qc
null
Colombeau's generalized functions are used to adapt the distributional approach to singular hypersurfaces in general relativity with signature change. Equations governing the dynamics of singular hypersurface is obtained and it is shown that matching leads to de Sitter space for the Lorentzian region. The matching is...
[ { "created": "Sat, 27 Jun 1998 06:57:48 GMT", "version": "v1" } ]
2007-05-23
[ [ "Mansouri", "Reza", "" ], [ "Nozari", "Kourosh", "" ] ]
Colombeau's generalized functions are used to adapt the distributional approach to singular hypersurfaces in general relativity with signature change. Equations governing the dynamics of singular hypersurface is obtained and it is shown that matching leads to de Sitter space for the Lorentzian region. The matching is p...
2207.10202
Tetsuya Shiromizu
Tetsuya Shiromizu, Keisuke Izumi, Kangjae Lee and Diego Soligon
Maximum size of black holes in our accelerating Universe
8 pages, minor corrections, to apper in PRD
null
null
null
gr-qc astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In accordance with current models of the accelerating Universe as a spacetime with a positive cosmological constant, new results about a cosmological upper bound for the area of stable marginally outer trapped surfaces are found taking into account angular momentum, gravitational waves and matter. Compared to previou...
[ { "created": "Wed, 20 Jul 2022 21:41:43 GMT", "version": "v1" }, { "created": "Mon, 10 Oct 2022 06:20:42 GMT", "version": "v2" } ]
2022-10-11
[ [ "Shiromizu", "Tetsuya", "" ], [ "Izumi", "Keisuke", "" ], [ "Lee", "Kangjae", "" ], [ "Soligon", "Diego", "" ] ]
In accordance with current models of the accelerating Universe as a spacetime with a positive cosmological constant, new results about a cosmological upper bound for the area of stable marginally outer trapped surfaces are found taking into account angular momentum, gravitational waves and matter. Compared to previous ...
1504.05818
A. N. Ivanov
A. N. Ivanov and M. Wellenzohn
Standard Electroweak Interactions in Gravitational Theory with Chameleon Field and Torsion
26 pages, 8 figures
Phys. Rev. D 91, 085025 (2015)
10.1103/PhysRevD.91.085025
null
gr-qc hep-ph nucl-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a version of a gravitational theory with the torsion field, induced by the chameleon field. Following Hojman et al. Phys. Rev. D17, 3141 (1976) the results, obtained in Phys. Rev. D90, 045040 (2014), are generalised by extending the Einstein gravity to the Einstein-Cartan gravity with the torsion field as ...
[ { "created": "Wed, 22 Apr 2015 14:18:49 GMT", "version": "v1" } ]
2015-04-23
[ [ "Ivanov", "A. N.", "" ], [ "Wellenzohn", "M.", "" ] ]
We propose a version of a gravitational theory with the torsion field, induced by the chameleon field. Following Hojman et al. Phys. Rev. D17, 3141 (1976) the results, obtained in Phys. Rev. D90, 045040 (2014), are generalised by extending the Einstein gravity to the Einstein-Cartan gravity with the torsion field as a ...
1312.7684
Farook Rahaman
Farook Rahaman, Ayan Banerjee, Mubasher Jamil, Anil Kumar Yadav, Humaira Idris
Noncommutative Wormholes in $f(R)$ Gravity with Lorentzian Distribution
9 apges 4 groups of plots. Accepted in Int.J.Theor.Phys
Int.J.Theor.Phys. (2014) 53:1910-1919
10.1007/s10773-013-1993-5
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we derive some new exact solutions of static wormholes in $f(R)$ gravity supported by the matter possesses Lorentizian density distribution of a particle-like gravitational source. We derive the wormhole's solutions in two possible schemes for a given Lorentzian distribution: assuming an astrophysicall...
[ { "created": "Mon, 30 Dec 2013 11:38:12 GMT", "version": "v1" } ]
2015-01-28
[ [ "Rahaman", "Farook", "" ], [ "Banerjee", "Ayan", "" ], [ "Jamil", "Mubasher", "" ], [ "Yadav", "Anil Kumar", "" ], [ "Idris", "Humaira", "" ] ]
In this paper, we derive some new exact solutions of static wormholes in $f(R)$ gravity supported by the matter possesses Lorentizian density distribution of a particle-like gravitational source. We derive the wormhole's solutions in two possible schemes for a given Lorentzian distribution: assuming an astrophysically ...
gr-qc/0607118
Alvaro De La Cruz-Dombriz
A. de la Cruz-Dombriz and A. Dobado
A f(R) gravity without cosmological constant
5 pages, no figures
Phys.Rev. D74 (2006) 087501
10.1103/PhysRevD.74.087501
null
gr-qc
null
In this work we consider the possibility of describing the current evolution of the universe, without the introduction of any cosmological constant or dark energy (DE), by modifying the Einstein-Hilbert (EH) action. In the context of the f(R) gravities within the metric formalism, we show that it is possible to find ...
[ { "created": "Wed, 26 Jul 2006 12:19:06 GMT", "version": "v1" } ]
2009-11-11
[ [ "de la Cruz-Dombriz", "A.", "" ], [ "Dobado", "A.", "" ] ]
In this work we consider the possibility of describing the current evolution of the universe, without the introduction of any cosmological constant or dark energy (DE), by modifying the Einstein-Hilbert (EH) action. In the context of the f(R) gravities within the metric formalism, we show that it is possible to find an...
2211.03092
Yakov Itin
Yakov Itin
Hilbert's energy-momentum tensor extended
null
null
null
null
gr-qc hep-th math-ph math.MP
http://creativecommons.org/licenses/by/4.0/
A variational derivative of a Lagrangian with regard to the metric tensor is used in classical field models to define Hilbert's energy-momentum tensor for a matter field. In solid-state physics, constitutive relationships between fundamental field variables are a topic that is covered by a broad variety of models. In...
[ { "created": "Sun, 6 Nov 2022 11:54:52 GMT", "version": "v1" } ]
2022-11-08
[ [ "Itin", "Yakov", "" ] ]
A variational derivative of a Lagrangian with regard to the metric tensor is used in classical field models to define Hilbert's energy-momentum tensor for a matter field. In solid-state physics, constitutive relationships between fundamental field variables are a topic that is covered by a broad variety of models. In t...
2107.12735
Diego Cruces Mateo
Diego Cruces and Cristiano Germani
Stochastic inflation at all order in slow-roll parameters: foundations
38 pages, 11 figures, typos corrected, ref added, results unchanged, accepted in Physical Review D
null
10.1103/PhysRevD.105.023533
null
gr-qc astro-ph.CO hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we develop the formalism for the stochastic approach to inflation at all order in slow-roll parameters. This is done by including the momentum and Hamiltonian constraints into the stochastic equations. We then specialise to the widely used Starobinski approximation where interactions between IR and UV m...
[ { "created": "Tue, 27 Jul 2021 11:29:25 GMT", "version": "v1" }, { "created": "Mon, 10 Jan 2022 20:12:10 GMT", "version": "v2" } ]
2022-02-09
[ [ "Cruces", "Diego", "" ], [ "Germani", "Cristiano", "" ] ]
In this paper we develop the formalism for the stochastic approach to inflation at all order in slow-roll parameters. This is done by including the momentum and Hamiltonian constraints into the stochastic equations. We then specialise to the widely used Starobinski approximation where interactions between IR and UV mod...
1411.1077
Steffen Gielen
Steffen Gielen
Perturbing a quantum gravity condensate
10 pages, APS style, revtex; v2: more discussion and references added, unchanged results, v3: minor changes to match journal version
Phys. Rev. D 91, 043526 (2015)
10.1103/PhysRevD.91.043526
Imperial/TP/2014/SG/1
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In a recent proposal using the group field theory approach, a spatially homogeneous (generally anisotropic) universe is described as a quantum gravity condensate of "atoms of space," which allows the derivation of an effective cosmological Friedmann equation from the microscopic quantum gravity dynamics. Here we take...
[ { "created": "Tue, 4 Nov 2014 21:04:22 GMT", "version": "v1" }, { "created": "Fri, 9 Jan 2015 19:34:19 GMT", "version": "v2" }, { "created": "Tue, 3 Feb 2015 19:40:25 GMT", "version": "v3" } ]
2015-02-23
[ [ "Gielen", "Steffen", "" ] ]
In a recent proposal using the group field theory approach, a spatially homogeneous (generally anisotropic) universe is described as a quantum gravity condensate of "atoms of space," which allows the derivation of an effective cosmological Friedmann equation from the microscopic quantum gravity dynamics. Here we take a...
1201.6672
Abel Camacho Mr.
A. Camacho (Departamento de F\'isica, Universidad Aut\'onoma Metropolitana--Iztapalapa, M\'exico) E. Castellanos (ZARM, Universit\"at Bremen, Am Fallturm, Bremen, Germany)
Ultra--cold gases and the detection of the Earth's rotation: Bogoliubov space and gravitomagnetism
4 pages
null
10.1142/S0217732312501982
null
gr-qc cond-mat.quant-gas
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The present work analyzes the consequences of the gravitomagnetic effect of the Earth upon a bosonic gas in which the corresponding atoms have a non--vanishing orbital angular momentum. Concerning the ground state of the Bogoliubov space of this system we deduce the consequences, on the pressure and on the speed of s...
[ { "created": "Tue, 31 Jan 2012 20:23:05 GMT", "version": "v1" } ]
2015-06-04
[ [ "Camacho", "A.", "", "Departamento de Física, Universidad Autónoma\n Metropolitana--Iztapalapa, México" ], [ "Castellanos", "E.", "", "ZARM, Universität\n Bremen, Am Fallturm, Bremen, Germany" ] ]
The present work analyzes the consequences of the gravitomagnetic effect of the Earth upon a bosonic gas in which the corresponding atoms have a non--vanishing orbital angular momentum. Concerning the ground state of the Bogoliubov space of this system we deduce the consequences, on the pressure and on the speed of sou...
2210.00837
Athanasios Lahanas
A. B. Lahanas
Issues in Palatini ${\cal{R}}^2$ inflation: Bounds on the Reheating Temperature
35 pages, 18 figures, PDFLaTeX, text and references added, typos corrected
null
10.1103/PhysRevD.106.123530
null
gr-qc astro-ph.CO hep-ph hep-th
http://creativecommons.org/licenses/by/4.0/
We consider ${\cal{R}}^2$-inflation in Palatini gravity, in the presence of scalar fields coupled to gravity. These theories, in the Einstein frame, and for one scalar field $h$, share common features with $K$ - inflation models. We apply this formalism for the study of single-field inflationary models, whose potenti...
[ { "created": "Mon, 3 Oct 2022 11:55:34 GMT", "version": "v1" }, { "created": "Tue, 18 Oct 2022 10:50:00 GMT", "version": "v2" }, { "created": "Thu, 15 Dec 2022 10:09:08 GMT", "version": "v3" } ]
2023-01-11
[ [ "Lahanas", "A. B.", "" ] ]
We consider ${\cal{R}}^2$-inflation in Palatini gravity, in the presence of scalar fields coupled to gravity. These theories, in the Einstein frame, and for one scalar field $h$, share common features with $K$ - inflation models. We apply this formalism for the study of single-field inflationary models, whose potential...
0904.2546
Pablo Hernan Pereyra
P. H. Pereyra
The Schwarzschild Static Cosmological Model
10 pages, 5 figures
Int.J.Mod.Phys.D16:553-562,2007
10.1142/S0218271807010390
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The present work describes an immersion in 5D of the interior Schwarzschild solution of the general relativity equations. The model theory is defined in the context of a flat 5D space time matter Minkowski model, using a Tolman like technique, which shows via Lorentz transformations that the solution is compatible wi...
[ { "created": "Thu, 16 Apr 2009 17:36:23 GMT", "version": "v1" } ]
2009-04-21
[ [ "Pereyra", "P. H.", "" ] ]
The present work describes an immersion in 5D of the interior Schwarzschild solution of the general relativity equations. The model theory is defined in the context of a flat 5D space time matter Minkowski model, using a Tolman like technique, which shows via Lorentz transformations that the solution is compatible with...
0706.0466
Aleksandar Mikovic
A. Mikovic
Spin Network Wavefunction and the Graviton Propagator
8 pages
null
10.1002/prop.200710522
null
gr-qc
null
We show that if the flat-spacetime wavefunction in the spin network basis of Loop Quantum Gravity has a large-spin asymptotics given by Rovelli's ansatz then the corresponding graviton propagator has the correct large-distance asymptotics nonperturbatively and independently of the spin foam model used to describe the...
[ { "created": "Mon, 4 Jun 2007 16:05:06 GMT", "version": "v1" } ]
2015-05-13
[ [ "Mikovic", "A.", "" ] ]
We show that if the flat-spacetime wavefunction in the spin network basis of Loop Quantum Gravity has a large-spin asymptotics given by Rovelli's ansatz then the corresponding graviton propagator has the correct large-distance asymptotics nonperturbatively and independently of the spin foam model used to describe the e...
1412.8124
Sunil Maharaj
P. Mafa Takisa, S. D. Maharaj, Subharthi Ray
Stellar objects in the quadratic regime
8 pages, Submitted for publication
Astrophys. Space Sci. 354: 463-470 (2014)
10.1007/s10509-014-2120-7
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We model a charged anisotropic relativistic star with a quadratic equation of state. Physical features of an exact solution of the Einstein-Maxwell system are studied by incorporating the effect of the nonlinear term from the equation of state. It is possible to regain the masses, radii and central densities for a li...
[ { "created": "Sun, 28 Dec 2014 07:29:05 GMT", "version": "v1" } ]
2015-06-23
[ [ "Takisa", "P. Mafa", "" ], [ "Maharaj", "S. D.", "" ], [ "Ray", "Subharthi", "" ] ]
We model a charged anisotropic relativistic star with a quadratic equation of state. Physical features of an exact solution of the Einstein-Maxwell system are studied by incorporating the effect of the nonlinear term from the equation of state. It is possible to regain the masses, radii and central densities for a line...
1905.02622
Haryanto Siahaan
Haryanto M. Siahaan
Kerr-Sen-Taub-NUT spacetime and circular geodesics
20 pages, 7 figures;V3, minor revisions; V2, refs added
null
10.1140/epjc/s10052-020-08561-z
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a novel solution obeying classical equation of motion in the low energy limit of heterotic string theory. The solution represents a rotating mass with electric charge and gravitomagnetic monopole moment. The corresponding conserved charges are discussed. We also study the test body circular equatorial moti...
[ { "created": "Tue, 7 May 2019 14:50:49 GMT", "version": "v1" }, { "created": "Sun, 30 Jun 2019 19:25:47 GMT", "version": "v2" }, { "created": "Tue, 5 May 2020 09:05:17 GMT", "version": "v3" }, { "created": "Sat, 23 May 2020 08:45:53 GMT", "version": "v4" } ]
2020-12-02
[ [ "Siahaan", "Haryanto M.", "" ] ]
We present a novel solution obeying classical equation of motion in the low energy limit of heterotic string theory. The solution represents a rotating mass with electric charge and gravitomagnetic monopole moment. The corresponding conserved charges are discussed. We also study the test body circular equatorial motion...
1507.01281
Stanley P. Gudder
Stan Gudder
Inflation and Dirac in the Causal Set Approach to Discrete Quantum Gravity
23 pages
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this approach to discrete quantum gravity the basic structural element is a covariant causal set ($c$-causet). The geometry of a $c$-causet is described by a shell-sequence that determines the discrete gravity of a universe. In this growth model, universes evolve in discrete time by adding new vertices to their ge...
[ { "created": "Sun, 5 Jul 2015 21:55:14 GMT", "version": "v1" } ]
2015-07-07
[ [ "Gudder", "Stan", "" ] ]
In this approach to discrete quantum gravity the basic structural element is a covariant causal set ($c$-causet). The geometry of a $c$-causet is described by a shell-sequence that determines the discrete gravity of a universe. In this growth model, universes evolve in discrete time by adding new vertices to their gene...
gr-qc/0003068
Pawel Zieba
W. Rudnicki, P. Zieba
On the strength of the Kerr singularity and cosmic censorship
RevTeX, 6 pages, no figures, to appear in Phys. Lett. A
Phys.Lett. A268 (2000) 228-234
10.1016/S0375-9601(00)00185-7
null
gr-qc
null
It has been suggested by Israel that the Kerr singularity cannot be strong in the sense of Tipler, for it tends to cause repulsive effects. We show here that, contrary to that suggestion, nearly all null geodesics reaching this singularity do in fact terminate in Tipler's strong curvature singularity. Implications of...
[ { "created": "Thu, 16 Mar 2000 14:06:42 GMT", "version": "v1" } ]
2009-10-31
[ [ "Rudnicki", "W.", "" ], [ "Zieba", "P.", "" ] ]
It has been suggested by Israel that the Kerr singularity cannot be strong in the sense of Tipler, for it tends to cause repulsive effects. We show here that, contrary to that suggestion, nearly all null geodesics reaching this singularity do in fact terminate in Tipler's strong curvature singularity. Implications of t...
1812.07168
Pujian Mao
Pujian Mao and Xiaoning Wu
More on gravitational memory
v3: presentation improved, discussion extended, typos corrected, refs. added v4: typos corrected
JHEP 05 (2019) 058
10.1007/JHEP05(2019)058
CJQS-2019-014
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Two novel results for the gravitational memory effect are presented in this paper. We first extend the formula for the memory effect to solutions with arbitrary two surface boundary topology. The memory effect for the Robinson-Trautman solution is obtained in its standard form. Then we propose a new observational eff...
[ { "created": "Tue, 18 Dec 2018 04:49:01 GMT", "version": "v1" }, { "created": "Tue, 8 Jan 2019 05:47:36 GMT", "version": "v2" }, { "created": "Fri, 10 May 2019 14:13:42 GMT", "version": "v3" }, { "created": "Thu, 10 Oct 2019 05:59:02 GMT", "version": "v4" } ]
2020-11-24
[ [ "Mao", "Pujian", "" ], [ "Wu", "Xiaoning", "" ] ]
Two novel results for the gravitational memory effect are presented in this paper. We first extend the formula for the memory effect to solutions with arbitrary two surface boundary topology. The memory effect for the Robinson-Trautman solution is obtained in its standard form. Then we propose a new observational effec...
1011.3126
Alexander Agathonov
Yurii Ignatyev and Alexander Agathonov
Exact Solutions of the Self-consistent System of Relativistic Magnetohydrodynamics Equations for an Anisotropic Plasma on the Background of Bondi-Pirani-Robinson's Metric
20 pages
null
null
null
gr-qc physics.plasm-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Exact solutions of the self-consistent relativistic magnetohydrodynamics equations for an anisotropic magnetized plasma on the background of Bondi-Pirani-Robinson's vacuum plane gravitational wave (PGW) metric with an arbitrary polarization are obtained, which generalize the results obtained earlier by one of the aut...
[ { "created": "Sat, 13 Nov 2010 11:28:32 GMT", "version": "v1" } ]
2010-11-16
[ [ "Ignatyev", "Yurii", "" ], [ "Agathonov", "Alexander", "" ] ]
Exact solutions of the self-consistent relativistic magnetohydrodynamics equations for an anisotropic magnetized plasma on the background of Bondi-Pirani-Robinson's vacuum plane gravitational wave (PGW) metric with an arbitrary polarization are obtained, which generalize the results obtained earlier by one of the autho...
1712.00577
Inyong Cho
Inyong Cho
Fluid Black Holes with Electric Field
11 pages, 6 figures. Version to appear in EPJC
null
null
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate the gravitational field of static perfect-fluid in the presence of electric field. We adopt the equation of state $p(r)=-\rho(r)/3$ for the fluid in order to consider the closed ($S_3$) or the open ($H_3$) background spatial topology. Depending on the scales of the mass, spatial-curvature and charge pa...
[ { "created": "Sat, 2 Dec 2017 09:23:39 GMT", "version": "v1" }, { "created": "Fri, 18 Jan 2019 05:14:48 GMT", "version": "v2" } ]
2019-01-21
[ [ "Cho", "Inyong", "" ] ]
We investigate the gravitational field of static perfect-fluid in the presence of electric field. We adopt the equation of state $p(r)=-\rho(r)/3$ for the fluid in order to consider the closed ($S_3$) or the open ($H_3$) background spatial topology. Depending on the scales of the mass, spatial-curvature and charge para...
1308.2770
Olivier Minazzoli
Olivier Minazzoli and Aur\'elien Hees
Intrinsic Solar System decoupling of a scalar-tensor theory with a universal coupling between the scalar field and the matter Lagrangian
Accepted for publication in Phys. Rev. D. 6 pages
Phys. Rev. D 88, 041504 (2013)
10.1103/PhysRevD.88.041504
null
gr-qc hep-th math-ph math.MP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this communication, we present a class of Brans-Dicke-like theories with a universal coupling between the scalar field and the matter Lagrangian. We show this class of theories naturally exhibits a decoupling mechanism between the scalar field and matter. As a consequence, this coupling leads to almost the same ph...
[ { "created": "Tue, 13 Aug 2013 07:10:42 GMT", "version": "v1" } ]
2013-09-03
[ [ "Minazzoli", "Olivier", "" ], [ "Hees", "Aurélien", "" ] ]
In this communication, we present a class of Brans-Dicke-like theories with a universal coupling between the scalar field and the matter Lagrangian. We show this class of theories naturally exhibits a decoupling mechanism between the scalar field and matter. As a consequence, this coupling leads to almost the same phen...
gr-qc/0107054
Sergio M. C. V. Goncalves
Sergio M. C. V. Goncalves (Caltech) and Sanjay Jhingan (YITP, Japan)
Singularities in gravitational collapse with radial pressure
to appear in GRG; LaTeX, 22 pages, 2 eps figures
Gen.Rel.Grav.33:2125-2149,2001
10.1023/A:1015285531320
null
gr-qc
null
We analyze spherical dust collapse with non-vanishing radial pressure, $\Pi$, and vanishing tangential stresses. Considering a barotropic equation of state, $\Pi=\gamma\rho$, we obtain an analytical solution in closed form---which is exact for $\gamma=-1,0$, and approximate otherwise---near the center of symmetry (wh...
[ { "created": "Mon, 16 Jul 2001 10:51:41 GMT", "version": "v1" } ]
2010-05-12
[ [ "Goncalves", "Sergio M. C. V.", "", "Caltech" ], [ "Jhingan", "Sanjay", "", "YITP, Japan" ] ]
We analyze spherical dust collapse with non-vanishing radial pressure, $\Pi$, and vanishing tangential stresses. Considering a barotropic equation of state, $\Pi=\gamma\rho$, we obtain an analytical solution in closed form---which is exact for $\gamma=-1,0$, and approximate otherwise---near the center of symmetry (wher...