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2407.20946
Anna Neuweiler
Anna Neuweiler, Tim Dietrich, Bernd Br\"ugmann, Edoardo Giangrandi, Kenta Kiuchi, Federico Schianchi, Philipp M\"osta, Swapnil Shankar, Bruno Giacomazzo, and Masaru Shibata
General Relativistic Magneto-Hydrodynamic Simulations with BAM: Implementation and Code Comparison
21 pages, 21 figures
null
null
null
gr-qc astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Binary neutron star mergers are among the most energetic events in our Universe, with magnetic fields significantly impacting their dynamics, particularly after the merger. While numerical-relativity simulations that correctly describe the physics are essential to model their rich phenomenology, the inclusion of magn...
[ { "created": "Tue, 30 Jul 2024 16:25:33 GMT", "version": "v1" } ]
2024-07-31
[ [ "Neuweiler", "Anna", "" ], [ "Dietrich", "Tim", "" ], [ "Brügmann", "Bernd", "" ], [ "Giangrandi", "Edoardo", "" ], [ "Kiuchi", "Kenta", "" ], [ "Schianchi", "Federico", "" ], [ "Mösta", "Philipp", "" ], ...
Binary neutron star mergers are among the most energetic events in our Universe, with magnetic fields significantly impacting their dynamics, particularly after the merger. While numerical-relativity simulations that correctly describe the physics are essential to model their rich phenomenology, the inclusion of magnet...
0902.0129
Hao Wei
Hao Wei
Entropy-Corrected Holographic Dark Energy
11 pages, 2 tables, revtex4; v2: references added
Commun.Theor.Phys.52:743-749,2009
10.1088/0253-6102/52/4/35
null
gr-qc astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The holographic dark energy (HDE) is now an interesting candidate of dark energy, which has been studied extensively in the literature. In the derivation of HDE, the black hole entropy plays an important role. In fact, the entropy-area relation can be modified due to loop quantum gravity or other reasons. With the mo...
[ { "created": "Sun, 1 Feb 2009 21:41:00 GMT", "version": "v1" }, { "created": "Mon, 7 Sep 2009 03:23:15 GMT", "version": "v2" } ]
2009-10-12
[ [ "Wei", "Hao", "" ] ]
The holographic dark energy (HDE) is now an interesting candidate of dark energy, which has been studied extensively in the literature. In the derivation of HDE, the black hole entropy plays an important role. In fact, the entropy-area relation can be modified due to loop quantum gravity or other reasons. With the modi...
1906.00404
Ion I. Cotaescu
Ion I. Cotaescu
Rest frame vacuum of the Dirac field on spatially flat FLRW spacetimes
5 pages, no figures
null
10.1140/epjc/s10052-019-7200-y
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In quantum theory of the free Dirac field on spatially flat FLRW spacetimes we introduce a new type of vacuum able to separate the positive and negative frequencies in the rest frames. This is refereed as the rest frame vacuum shoving that this differs from the adiabatic vacuum apart from the Minkowski spacetime wher...
[ { "created": "Sun, 2 Jun 2019 13:51:06 GMT", "version": "v1" }, { "created": "Thu, 6 Jun 2019 13:12:56 GMT", "version": "v2" } ]
2019-09-04
[ [ "Cotaescu", "Ion I.", "" ] ]
In quantum theory of the free Dirac field on spatially flat FLRW spacetimes we introduce a new type of vacuum able to separate the positive and negative frequencies in the rest frames. This is refereed as the rest frame vacuum shoving that this differs from the adiabatic vacuum apart from the Minkowski spacetime where ...
2305.05042
Ramon Herrera
Ramon Herrera, Michel Housset, Constanza Osses and Nelson Videla
Reconstructing k-inflation from $n_s(N)$ and reheating constraints
40 pages and 6 figures
null
null
null
gr-qc astro-ph.CO hep-th
http://creativecommons.org/licenses/by/4.0/
Inspired by the reconstruction scheme of the inflaton field potential $V(\phi)$ from the attractors$n_s(N)$, we investigate the viability of reconstruct the inflationary potential within the framework of k-inflation for a non-linear kinetic term $K(X)=k_{n+1}X^n$ through three expressions for the scalar spectral inde...
[ { "created": "Mon, 8 May 2023 20:56:34 GMT", "version": "v1" } ]
2023-05-10
[ [ "Herrera", "Ramon", "" ], [ "Housset", "Michel", "" ], [ "Osses", "Constanza", "" ], [ "Videla", "Nelson", "" ] ]
Inspired by the reconstruction scheme of the inflaton field potential $V(\phi)$ from the attractors$n_s(N)$, we investigate the viability of reconstruct the inflationary potential within the framework of k-inflation for a non-linear kinetic term $K(X)=k_{n+1}X^n$ through three expressions for the scalar spectral index ...
1807.09056
Antoine Folacci
Antoine Folacci and Mohamed Ould El Hadj
An alternative description of gravitational radiation from black holes based on the Regge poles of the ${\cal S}$-matrix and the associated residues
v2 : minor changes and a few typos corrected. v3: One typo corrected and minor changes in the text to match the published version. v4: The sense of the contour in Eqs. (50) and (51) as well as a global sign in Eq. (53) have been corrected. (Results unchanged because calculations have been performed with the rig...
Phys. Rev. D 98, 064052 (2018)
10.1103/PhysRevD.98.064052
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We advocate for an alternative description of gravitational radiation from black holes based on complex angular momentum techniques (analytic continuation of partial wave expansions, duality of the ${\cal S}$-matrix and effective resummations involving its Regge poles and the associated residues, Regge trajectories, ...
[ { "created": "Tue, 24 Jul 2018 12:02:44 GMT", "version": "v1" }, { "created": "Mon, 17 Sep 2018 14:10:57 GMT", "version": "v2" }, { "created": "Thu, 27 Sep 2018 11:50:35 GMT", "version": "v3" }, { "created": "Wed, 15 Apr 2020 18:13:36 GMT", "version": "v4" } ]
2020-04-17
[ [ "Folacci", "Antoine", "" ], [ "Hadj", "Mohamed Ould El", "" ] ]
We advocate for an alternative description of gravitational radiation from black holes based on complex angular momentum techniques (analytic continuation of partial wave expansions, duality of the ${\cal S}$-matrix and effective resummations involving its Regge poles and the associated residues, Regge trajectories, se...
1711.09027
Jerzy Kr\'ol
Michael Heller and Jerzy Kr\'ol
Beyond the Space-Time Boundary
10 pages
null
null
null
gr-qc math-ph math.MP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In General Relativity a space-time $M$ is regarded singular if there is an obstacle that prevents an incomplete curve in $M$ to be continued. Usually, such a space-time is completed to form $\bar{M} = M \cup \partial M$ where $\partial M$ is a singular boundary of $M$. The standard geometric tools on $M$ do not allow...
[ { "created": "Fri, 24 Nov 2017 15:55:48 GMT", "version": "v1" } ]
2017-11-27
[ [ "Heller", "Michael", "" ], [ "Król", "Jerzy", "" ] ]
In General Relativity a space-time $M$ is regarded singular if there is an obstacle that prevents an incomplete curve in $M$ to be continued. Usually, such a space-time is completed to form $\bar{M} = M \cup \partial M$ where $\partial M$ is a singular boundary of $M$. The standard geometric tools on $M$ do not allow "...
1608.06089
Kalin Marinov Mr.
Plamen Fiziev, Kalin Marinov
Modeling of non-rotating neutron stars in minimal dilatonic gravity
12 pages, 17 figures, LaTeX file, new section added, 2 new figures added, final published version
Astrophys Space Sci (2017) 362: 8
10.1007/s10509-016-2991-x
null
gr-qc astro-ph.SR
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The model of minimal dilatonic gravity (MDG), called also the massive Branse-Dicke model with $\omega =0$, is an alternative model of gravitation, which uses one Branse-Dicke gravitation-dilaton field $\Phi$ and offers a simultaneous explanation of the effects of dark energy (DE) and dark matter (DM). Here we present...
[ { "created": "Mon, 22 Aug 2016 08:56:38 GMT", "version": "v1" }, { "created": "Tue, 13 Dec 2016 12:49:49 GMT", "version": "v2" } ]
2016-12-14
[ [ "Fiziev", "Plamen", "" ], [ "Marinov", "Kalin", "" ] ]
The model of minimal dilatonic gravity (MDG), called also the massive Branse-Dicke model with $\omega =0$, is an alternative model of gravitation, which uses one Branse-Dicke gravitation-dilaton field $\Phi$ and offers a simultaneous explanation of the effects of dark energy (DE) and dark matter (DM). Here we present a...
1812.05468
Maciej Dunajski
Maciej Dunajski, Paul Tod
Conformally isometric embeddings and Hawking temperature
Final version, to appear in Classical and Quantum Gravity
null
10.1088/1361-6382/ab2068
DAMTP-2018-42
gr-qc hep-th math.DG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We find necessary and sufficient conditions for existence of a locally isometric embedding of a vacuum space-time into a conformally-flat 5-space. We explicitly construct such embeddings for any spherically symmetric Lorentzian metric in $3+1$ dimensions as a hypersurface in $R^{4, 1}$. For the Schwarzschild metric t...
[ { "created": "Thu, 13 Dec 2018 14:57:57 GMT", "version": "v1" }, { "created": "Tue, 21 May 2019 13:46:45 GMT", "version": "v2" } ]
2019-09-04
[ [ "Dunajski", "Maciej", "" ], [ "Tod", "Paul", "" ] ]
We find necessary and sufficient conditions for existence of a locally isometric embedding of a vacuum space-time into a conformally-flat 5-space. We explicitly construct such embeddings for any spherically symmetric Lorentzian metric in $3+1$ dimensions as a hypersurface in $R^{4, 1}$. For the Schwarzschild metric the...
gr-qc/9608050
Bernd Bruegmann
Bernd Bruegmann
Adaptive mesh and geodesically sliced Schwarzschild spacetime in 3+1 dimensions
21 pages, LaTeX, 7 figures included with epsf
Phys.Rev.D54:7361-7372,1996
10.1103/PhysRevD.54.7361
null
gr-qc
null
We present first results obtained with a 3+1 dimensional adaptive mesh code in numerical general relativity. The adaptive mesh is used in conjunction with a standard ADM code for the evolution of a dynamically sliced Schwarzschild spacetime (geodesic slicing). We argue that adaptive mesh is particularly natural in th...
[ { "created": "Wed, 21 Aug 1996 14:37:28 GMT", "version": "v1" } ]
2008-11-26
[ [ "Bruegmann", "Bernd", "" ] ]
We present first results obtained with a 3+1 dimensional adaptive mesh code in numerical general relativity. The adaptive mesh is used in conjunction with a standard ADM code for the evolution of a dynamically sliced Schwarzschild spacetime (geodesic slicing). We argue that adaptive mesh is particularly natural in the ...
1005.2360
Clovis Jacinto de Matos
Clovis Jacinto de Matos
Are Superfluid Vortices in Pulsars Violating the Weak Equivalence Principle?
15 pages
null
null
null
gr-qc astro-ph.SR cond-mat.other
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In the present paper we argue that timing irregularities in pulsars, like glitches and timing noise, could be associated with the violation of the weak equivalence principle for vortices in the superfluid core of rotating neutron stars.
[ { "created": "Tue, 11 May 2010 10:14:51 GMT", "version": "v1" }, { "created": "Wed, 3 Nov 2010 10:11:39 GMT", "version": "v2" } ]
2010-11-04
[ [ "de Matos", "Clovis Jacinto", "" ] ]
In the present paper we argue that timing irregularities in pulsars, like glitches and timing noise, could be associated with the violation of the weak equivalence principle for vortices in the superfluid core of rotating neutron stars.
gr-qc/9911027
Gabriela Gonzalez
Mark A. Beilby, Gabriela Gonzalez, Michelle Duffy, Amber Stuver, Jennifer Poker
Development of a Double Pendulum for Gravitational Wave Detectors
one page, one figure, RevTeX, to appear in the proceedings of the Third Amaldi conference
null
10.1063/1.1291907
CGPG-99/11-5
gr-qc
null
Seismic noise will be the dominant source of noise at low frequencies for ground based gravitational wave detectors, such as LIGO now under construction. Future interferometers installed at LIGO plan to use at least a double pendulum suspension for the test masses to help filter the seismic noise. We are constructing...
[ { "created": "Mon, 8 Nov 1999 18:41:36 GMT", "version": "v1" } ]
2009-10-31
[ [ "Beilby", "Mark A.", "" ], [ "Gonzalez", "Gabriela", "" ], [ "Duffy", "Michelle", "" ], [ "Stuver", "Amber", "" ], [ "Poker", "Jennifer", "" ] ]
Seismic noise will be the dominant source of noise at low frequencies for ground based gravitational wave detectors, such as LIGO now under construction. Future interferometers installed at LIGO plan to use at least a double pendulum suspension for the test masses to help filter the seismic noise. We are constructing a...
1401.7251
Yaron Hadad
Yaron Hadad and Vladimir Zakharov
Transparency of Strong Gravitational Waves
null
null
10.1016/j.geomphys.2014.02.004
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper studies diagonal spacetime metrics. It is shown that the overdetermined Einstein vacuum equations are compatible if one Killing vector exists. The stability of plane gravitational waves of the Robinson type is studied. This stability problem bares a fantastic mathematical resemblance to the stability of th...
[ { "created": "Tue, 28 Jan 2014 16:39:46 GMT", "version": "v1" }, { "created": "Wed, 5 Feb 2014 15:12:30 GMT", "version": "v2" } ]
2015-06-18
[ [ "Hadad", "Yaron", "" ], [ "Zakharov", "Vladimir", "" ] ]
This paper studies diagonal spacetime metrics. It is shown that the overdetermined Einstein vacuum equations are compatible if one Killing vector exists. The stability of plane gravitational waves of the Robinson type is studied. This stability problem bares a fantastic mathematical resemblance to the stability of the ...
0911.0769
Sergey Cherkas L
S. V. Anischenko, S. L. Cherkas, V. L. Kalashnikov
Cosmological production of fermions in a flat Friedman universe with linearly growing scale factor: exactly solvable model
Mathematica notebook with details of calculations is available under request
Nonlin.Phenom.Complex Syst.13:315-319,2010
null
null
gr-qc hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider an exactly solvable model for production of fermions in the Friedman flat universe with a scale factor linearly growing with time. Exact solution expressed through the special functions admit an analytical calculation of the number density of created particles. We also discuss in general the role of the p...
[ { "created": "Wed, 4 Nov 2009 10:23:16 GMT", "version": "v1" }, { "created": "Wed, 24 Feb 2010 13:25:24 GMT", "version": "v2" }, { "created": "Sat, 20 Mar 2010 07:54:08 GMT", "version": "v3" } ]
2011-01-04
[ [ "Anischenko", "S. V.", "" ], [ "Cherkas", "S. L.", "" ], [ "Kalashnikov", "V. L.", "" ] ]
We consider an exactly solvable model for production of fermions in the Friedman flat universe with a scale factor linearly growing with time. Exact solution expressed through the special functions admit an analytical calculation of the number density of created particles. We also discuss in general the role of the phe...
gr-qc/0507074
Ewa Czuchry
Jerzy Kijowski and Ewa Czuchry
Dynamics of a self-gravitating shell of matter
published
Phys. Rev. D 72, 084015 (2005)
10.1103/PhysRevD.72.084015
null
gr-qc
null
Dynamics of a self-gravitating shell of matter is derived from the Hilbert variational principle and then described as an (infinite dimensional, constrained) Hamiltonian system. A method used here enables us to define singular Riemann tensor of a non-continuous connection {\em via} standard formulae of differential g...
[ { "created": "Mon, 18 Jul 2005 11:44:25 GMT", "version": "v1" }, { "created": "Mon, 14 Nov 2005 20:29:20 GMT", "version": "v2" } ]
2009-11-11
[ [ "Kijowski", "Jerzy", "" ], [ "Czuchry", "Ewa", "" ] ]
Dynamics of a self-gravitating shell of matter is derived from the Hilbert variational principle and then described as an (infinite dimensional, constrained) Hamiltonian system. A method used here enables us to define singular Riemann tensor of a non-continuous connection {\em via} standard formulae of differential geo...
1404.2284
Hamsa Padmanabhan
T. Padmanabhan and Hamsa Padmanabhan
Cosmological Constant from the Emergent Gravity Perspective
Invited review to appear in Int. Jour. Mod. Phys. D; 48 pages; 5 figures
Int. Jour. Mod. Phys. D, Vol. 23, No. 6 (2014) 1430011
10.1142/S0218271814300110
null
gr-qc astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Observations indicate that our universe is characterized by a late-time accelerating phase, possibly driven by a cosmological constant $\Lambda$, with the dimensionless parameter $\Lambda L_P^2 \simeq 10^{-122}$, where $L_P = (G \hbar /c^3)^{1/2}$ is the Planck length. In this review, we describe how the emergent gra...
[ { "created": "Tue, 8 Apr 2014 20:00:22 GMT", "version": "v1" } ]
2014-06-04
[ [ "Padmanabhan", "T.", "" ], [ "Padmanabhan", "Hamsa", "" ] ]
Observations indicate that our universe is characterized by a late-time accelerating phase, possibly driven by a cosmological constant $\Lambda$, with the dimensionless parameter $\Lambda L_P^2 \simeq 10^{-122}$, where $L_P = (G \hbar /c^3)^{1/2}$ is the Planck length. In this review, we describe how the emergent gravi...
0807.3158
Timothy Sumner
M.B. Gerrard and T.J. Sumner
Earth Flyby and Pioneer Anomalies
17 pages, 4 figures. V2 Updated with clarified angle definitions and formatting. V3 clearer diagrams, revised tables, addendum considering virtual accelerations
null
null
null
gr-qc physics.space-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Applying Newtonian dynamics in five dimensions rather than four, to a universe that is closed, isotropic and expanding,suggests that under certain circumstances an additional and previously unidentified acceleration, a_A, can arise affecting the four dimensional motion of spacecraft. The two cases of this acceleratio...
[ { "created": "Sun, 20 Jul 2008 14:19:58 GMT", "version": "v1" }, { "created": "Wed, 1 Oct 2008 12:56:50 GMT", "version": "v2" }, { "created": "Fri, 9 Apr 2010 14:21:59 GMT", "version": "v3" } ]
2010-04-12
[ [ "Gerrard", "M. B.", "" ], [ "Sumner", "T. J.", "" ] ]
Applying Newtonian dynamics in five dimensions rather than four, to a universe that is closed, isotropic and expanding,suggests that under certain circumstances an additional and previously unidentified acceleration, a_A, can arise affecting the four dimensional motion of spacecraft. The two cases of this acceleration ...
gr-qc/0512006
Abhas Mitra
Abhas Mitra
Comments on "Derivation of the Raychaudhuri Equation" by Dadhich
3 new references added, 2 of them are specific examples where collapse generated radiation presuure prevents formation of Trapped Surfaces
null
null
null
gr-qc
null
In a recent preprint, gr-qc/0511123, Dadhich has given a brief yet beautiful exposition on some of the research works by Prof. A.K. Raychaudhuri. Here Dadhich highlights the fact that the apparently ``self-evident'' assumption of occurrence of ``trapped surfaces'' may not be realized atleast in some specific cosmolog...
[ { "created": "Thu, 1 Dec 2005 09:10:53 GMT", "version": "v1" }, { "created": "Wed, 7 Dec 2005 11:39:02 GMT", "version": "v2" } ]
2007-05-23
[ [ "Mitra", "Abhas", "" ] ]
In a recent preprint, gr-qc/0511123, Dadhich has given a brief yet beautiful exposition on some of the research works by Prof. A.K. Raychaudhuri. Here Dadhich highlights the fact that the apparently ``self-evident'' assumption of occurrence of ``trapped surfaces'' may not be realized atleast in some specific cosmologic...
1006.2417
Maurizio Gasperini
A. Barone, M. Gasperini and G. Rotoli
Macroscopic Quantum Tunneling and the "cosmic" Josephson effect
4 pages, 1 pdf figure. Added references and an inset in Fig. 1, results unchanged. To appear in Phys. Rev. D (Brief Report)
Phys.Rev.D82:087301,2010
10.1103/PhysRevD.82.087301
BA-TH/628-10
gr-qc astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss the possible influence of a cosmic magnetic field on the macroscopic quantum tunneling process associated, in a cosmological context, to the decay of the "false vacuum." We find a close analogy with the effects of an external magnetic field applied to a Josephson junction in the context of low-temperature/...
[ { "created": "Fri, 11 Jun 2010 23:12:43 GMT", "version": "v1" }, { "created": "Sat, 25 Sep 2010 10:02:45 GMT", "version": "v2" } ]
2014-11-21
[ [ "Barone", "A.", "" ], [ "Gasperini", "M.", "" ], [ "Rotoli", "G.", "" ] ]
We discuss the possible influence of a cosmic magnetic field on the macroscopic quantum tunneling process associated, in a cosmological context, to the decay of the "false vacuum." We find a close analogy with the effects of an external magnetic field applied to a Josephson junction in the context of low-temperature/hi...
1606.02932
Yi Xie
Xu Lu and Feng-Wei Yang and Yi Xie
Strong gravitational field time delay for photons coupled to Weyl tensor in a Schwarzschild black hole
8 pages, 3 figures
Eur. Phys. J. C (2016) 76: 357
10.1140/epjc/s10052-016-4218-2
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We analyse strong gravitational field time delay for photons coupled to the Weyl tensor in a Schwarzschild black hole. By making use of the method of strong deflection limit, we find that these time delays between relativistic images are significantly affected by polarization directions of such a coupling. A practica...
[ { "created": "Thu, 9 Jun 2016 12:29:50 GMT", "version": "v1" } ]
2016-07-05
[ [ "Lu", "Xu", "" ], [ "Yang", "Feng-Wei", "" ], [ "Xie", "Yi", "" ] ]
We analyse strong gravitational field time delay for photons coupled to the Weyl tensor in a Schwarzschild black hole. By making use of the method of strong deflection limit, we find that these time delays between relativistic images are significantly affected by polarization directions of such a coupling. A practical ...
gr-qc/0505017
Arundhati Dasgupta
Arundhati Dasgupta
Semiclassical quantisation of space-times with apparent horizons
52 pages, 4 figures
Class.Quant.Grav. 23 (2006) 635-672
10.1088/0264-9381/23/3/007
null
gr-qc astro-ph hep-th
null
Coherent or semiclassical states in canonical quantum gravity describe the classical Schwarzschild space-time. By tracing over the coherent state wavefunction inside the horizon, a density matrix is derived. Bekenstein-Hawking entropy is obtained from the density matrix, modulo the Immirzi parameter. The expectation ...
[ { "created": "Tue, 3 May 2005 21:38:01 GMT", "version": "v1" }, { "created": "Mon, 16 Jan 2006 00:33:03 GMT", "version": "v2" } ]
2009-11-11
[ [ "Dasgupta", "Arundhati", "" ] ]
Coherent or semiclassical states in canonical quantum gravity describe the classical Schwarzschild space-time. By tracing over the coherent state wavefunction inside the horizon, a density matrix is derived. Bekenstein-Hawking entropy is obtained from the density matrix, modulo the Immirzi parameter. The expectation va...
gr-qc/0507100
Ioannis Raptis
Ioannis Raptis
Finitary Topos for Locally Finite, Causal and Quantal Vacuum Einstein Gravity
49 pages, latest updated version (errata corrected, references polished) Submitted to the International Journal of Theoretical Physics
Int.J.Theor.Phys.46:688-739,2007
10.1007/s10773-006-9240-y
null
gr-qc
null
Previous work on applications of Abstract Differential Geometry (ADG) to discrete Lorentzian quantum gravity is brought to its categorical climax by organizing the curved finitary spacetime sheaves of quantum causal sets involved therein, on which a finitary (:locally finite), singularity-free, background manifold in...
[ { "created": "Sun, 24 Jul 2005 21:15:25 GMT", "version": "v1" }, { "created": "Thu, 11 Aug 2005 09:35:12 GMT", "version": "v2" }, { "created": "Wed, 21 Sep 2005 11:51:35 GMT", "version": "v3" } ]
2008-11-26
[ [ "Raptis", "Ioannis", "" ] ]
Previous work on applications of Abstract Differential Geometry (ADG) to discrete Lorentzian quantum gravity is brought to its categorical climax by organizing the curved finitary spacetime sheaves of quantum causal sets involved therein, on which a finitary (:locally finite), singularity-free, background manifold inde...
1308.6155
Xavier Calmet
Xavier Calmet
Effective theory for quantum gravity
5 pages. This essay received an "honorable mention" in the 2013 Essay Competition of the Gravity Research Foundation
null
10.1142/S0218271813420145
null
gr-qc hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we discuss an effective theory for quantum gravity and discuss the bounds on the parameters of this effective action. In particular we show that measurement in pulsars binary systems are unlikely to improve the bounds on the coefficients of the $R^2$ and $R_{\mu\nu} R^{\mu\nu}$ terms obtained from prob...
[ { "created": "Wed, 28 Aug 2013 14:03:13 GMT", "version": "v1" } ]
2015-06-17
[ [ "Calmet", "Xavier", "" ] ]
In this paper, we discuss an effective theory for quantum gravity and discuss the bounds on the parameters of this effective action. In particular we show that measurement in pulsars binary systems are unlikely to improve the bounds on the coefficients of the $R^2$ and $R_{\mu\nu} R^{\mu\nu}$ terms obtained from probes...
gr-qc/0108001
Stoytcho Yazadjiev
Stoytcho S. Yazadjiev (Sofia University)
Solution generating in scalar-tensor theories with a massless scalar field and stiff perfect fluid as a source
10 pages,Revtex; v2 extended version, new parts added and some parts rewritten, results presented more concisely, some simple examples of homogeneous solutions replaced with new regular inhomogeneous solutions, typos corrected, references and acknowledgements added, accepted for publication in Phys.Rev.D
Phys.Rev.D65:084023,2002
10.1103/PhysRevD.65.084023
null
gr-qc hep-th
null
We present a method for generating solutions in some scalar-tensor theories with a minimally coupled massless scalar field or irrotational stiff perfect fluid as a source. The method is based on the group of symmetries of the dilaton-matter sector in the Einstein frame. In the case of Barker's theory the dilaton-matt...
[ { "created": "Wed, 1 Aug 2001 06:19:49 GMT", "version": "v1" }, { "created": "Sun, 20 Jan 2002 11:04:39 GMT", "version": "v2" } ]
2014-11-17
[ [ "Yazadjiev", "Stoytcho S.", "", "Sofia University" ] ]
We present a method for generating solutions in some scalar-tensor theories with a minimally coupled massless scalar field or irrotational stiff perfect fluid as a source. The method is based on the group of symmetries of the dilaton-matter sector in the Einstein frame. In the case of Barker's theory the dilaton-matter...
gr-qc/9808024
Kip S. Thorne
Kip S. Thorne (Caltech and Max-Planck-Insititut-fur-GravitationsPhysik)
Numerical Relativity for Inspiraling Binaries in Co-Rotating Coordinates: Test Bed for Lapse and Shift Equations
4 pages; submitted to Physical Review D15 as a regular article
null
null
null
gr-qc
null
Gravitational-wave data analysis requires a detailed understanding of the highly relativistic, late stages of inspiral of neutron-star and black-hole binaries. A promising method to compute the late inspiral and its emitted waves is numerical relativity in co-rotating coordinates. The coordinates must be kept co-rota...
[ { "created": "Sun, 9 Aug 1998 01:16:01 GMT", "version": "v1" } ]
2007-05-23
[ [ "Thorne", "Kip S.", "", "Caltech and\n Max-Planck-Insititut-fur-GravitationsPhysik" ] ]
Gravitational-wave data analysis requires a detailed understanding of the highly relativistic, late stages of inspiral of neutron-star and black-hole binaries. A promising method to compute the late inspiral and its emitted waves is numerical relativity in co-rotating coordinates. The coordinates must be kept co-rotati...
1802.02003
Yu-Tong Wang
Yu-Tong Wang, Zhi-Peng Li, Jun Zhang, Shuang-Yong Zhou, Yun-Song Piao
Are gravitational wave ringdown echoes always equal-interval ?
10 pages,5 figures
EPJC 78 (2018) 482
10.1140/epjc/s10052-018-5974-y
USTC-ICTS-18-04
gr-qc astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Gravitational wave (GW) ringdown waveforms may contain "echoes" that encode new physics in the strong gravity regime. It is commonly assumed that the new physics gives rise to the GW echoes whose intervals are constant. We point out that this assumption is not always applicable. In particular, if the post-merger obje...
[ { "created": "Tue, 6 Feb 2018 15:30:45 GMT", "version": "v1" }, { "created": "Wed, 7 Feb 2018 07:25:52 GMT", "version": "v2" }, { "created": "Wed, 13 Jun 2018 05:20:02 GMT", "version": "v3" } ]
2018-06-14
[ [ "Wang", "Yu-Tong", "" ], [ "Li", "Zhi-Peng", "" ], [ "Zhang", "Jun", "" ], [ "Zhou", "Shuang-Yong", "" ], [ "Piao", "Yun-Song", "" ] ]
Gravitational wave (GW) ringdown waveforms may contain "echoes" that encode new physics in the strong gravity regime. It is commonly assumed that the new physics gives rise to the GW echoes whose intervals are constant. We point out that this assumption is not always applicable. In particular, if the post-merger object...
gr-qc/0308026
Charles Wang
Charles Wang
Nonlinear parametric quantization of gravity and cosmological models
LaTex; 6 pages
null
null
null
gr-qc
null
A generalization of the recently formulated nonlinear quantization of a parameterized theory is presented in the context of quantum gravity. The parametric quantization of a Friedmann universe with a massless scalar field is then considered in terms of analytic solutions of the resulting evolution equations.
[ { "created": "Sun, 10 Aug 2003 17:28:26 GMT", "version": "v1" }, { "created": "Tue, 12 Aug 2003 08:50:57 GMT", "version": "v2" }, { "created": "Wed, 13 Aug 2003 00:15:10 GMT", "version": "v3" }, { "created": "Mon, 18 Aug 2003 10:37:28 GMT", "version": "v4" } ]
2007-05-23
[ [ "Wang", "Charles", "" ] ]
A generalization of the recently formulated nonlinear quantization of a parameterized theory is presented in the context of quantum gravity. The parametric quantization of a Friedmann universe with a massless scalar field is then considered in terms of analytic solutions of the resulting evolution equations.
0812.2767
Jose M. M. Senovilla
Jos\'e M.M. Senovilla
On the boundary of the region containing trapped surfaces
16 pages, 1 Table, 3 Figures. Invited talk to appear in the proceedings of the Spanish Relativity Meeting ERE-08, Salamanca, "Physics and Mathematics of Gravitation". Largely based on a collaboration with I. Bengtsson
null
10.1063/1.3141345
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The boundary of the region in spacetime containing future-trapped closed surfaces is considered. In asymptotically flat spacetimes, this boundary does not need to be the event horizon nor a dynamical/trapping horizon. Some properties of this boundary and its localization are analyzed, and illustrated with examples. I...
[ { "created": "Mon, 15 Dec 2008 11:14:19 GMT", "version": "v1" } ]
2015-05-13
[ [ "Senovilla", "José M. M.", "" ] ]
The boundary of the region in spacetime containing future-trapped closed surfaces is considered. In asymptotically flat spacetimes, this boundary does not need to be the event horizon nor a dynamical/trapping horizon. Some properties of this boundary and its localization are analyzed, and illustrated with examples. In ...
0908.2648
Jerzy Matyjasek
Jerzy Matyjasek and Dariusz Tryniecki
$AdS_{2} \times S^{2}$ geometries and the extreme quantum-corrected black holes
null
Mod.Phys.Lett.A24:2517-2530,2009
10.1142/S0217732309031910
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The second-order term of the approximate stress-energy tensor of the quantized massive scalar field in the Bertotti-Robinson and Reissner- Nordstr\"om spacetimes is constructed within the framework of the Schwinger-DeWitt method. It is shown that although the Bertotti- Robinson geometry is a self-consistent solution ...
[ { "created": "Tue, 18 Aug 2009 22:05:14 GMT", "version": "v1" } ]
2010-03-25
[ [ "Matyjasek", "Jerzy", "" ], [ "Tryniecki", "Dariusz", "" ] ]
The second-order term of the approximate stress-energy tensor of the quantized massive scalar field in the Bertotti-Robinson and Reissner- Nordstr\"om spacetimes is constructed within the framework of the Schwinger-DeWitt method. It is shown that although the Bertotti- Robinson geometry is a self-consistent solution of...
2403.03982
Aniruddha Chakraborty
Aniruddha Chakraborty, Suvodip Mukherjee
GLANCE -- Gravitational Lensing Authenticator using Non-Modelled Cross-Correlation Exploration of Gravitational Wave Signals
22 pages, 26 figures (including appendices). Accepted for publication in MNRAS
null
null
null
gr-qc astro-ph.CO
http://creativecommons.org/licenses/by-nc-nd/4.0/
Gravitational lensing is the phenomenon where the presence of matter (called a lens) bends the path of light-like trajectories travelling nearby. Similar to the geometric optics limit of electromagnetic waves, gravitational lensing of gravitational waves (GWs) can occur in geometric optics condition when GW wavelengt...
[ { "created": "Wed, 6 Mar 2024 19:00:10 GMT", "version": "v1" }, { "created": "Tue, 23 Jul 2024 09:54:13 GMT", "version": "v2" } ]
2024-07-24
[ [ "Chakraborty", "Aniruddha", "" ], [ "Mukherjee", "Suvodip", "" ] ]
Gravitational lensing is the phenomenon where the presence of matter (called a lens) bends the path of light-like trajectories travelling nearby. Similar to the geometric optics limit of electromagnetic waves, gravitational lensing of gravitational waves (GWs) can occur in geometric optics condition when GW wavelength ...
gr-qc/9502044
Mark Miller
Mark A. Miller (Syracuse University)
Regge Calculus as a Fourth Order Method in Numerical Relativity
14 pages, LaTeX, 8 figures mailed in separate file or email author directly
Class.Quant.Grav. 12 (1995) 3037-3052
10.1088/0264-9381/12/12/019
SU-GP-95/2-1
gr-qc
null
The convergence properties of numerical Regge calculus as an approximation to continuum vacuum General Relativity is studied, both analytically and numerically. The Regge equations are evaluated on continuum spacetimes by assigning squared geodesic distances in the continuum manifold to the squared edge lengths in th...
[ { "created": "Mon, 27 Feb 1995 22:23:59 GMT", "version": "v1" } ]
2016-08-31
[ [ "Miller", "Mark A.", "", "Syracuse University" ] ]
The convergence properties of numerical Regge calculus as an approximation to continuum vacuum General Relativity is studied, both analytically and numerically. The Regge equations are evaluated on continuum spacetimes by assigning squared geodesic distances in the continuum manifold to the squared edge lengths in the ...
2308.05025
Tanisha Joshi
Tanisha Joshi, S.D Pathak
Evolution of Entropy with Cosmic Time
null
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Understanding the evolution of entropy in the universe is a fundamental aspect of cosmology. This paper investigates the evolution of entropy in a spatially flat $K=0$ universe, focusing on the contributions of matter, radiation, and dark energy components. The study derives the rate of change of entropy with respect...
[ { "created": "Wed, 9 Aug 2023 15:44:38 GMT", "version": "v1" } ]
2023-08-10
[ [ "Joshi", "Tanisha", "" ], [ "Pathak", "S. D", "" ] ]
Understanding the evolution of entropy in the universe is a fundamental aspect of cosmology. This paper investigates the evolution of entropy in a spatially flat $K=0$ universe, focusing on the contributions of matter, radiation, and dark energy components. The study derives the rate of change of entropy with respect t...
gr-qc/9601026
Malcolm 'Schizoid' Tobias
Peter Anninos, Joan Masso, Edward Seidel, Wai-Mo Suen, Malcolm Tobias
The Near-Linear Regime of Gravitational Waves in Numerical Relativity
10 pages, 2 postscript figures, revised text
Phys.Rev.D54:6544-6547,1996
10.1103/PhysRevD.54.6544
wugrav-95-19
gr-qc
null
We report on a systematic study of the dynamics of gravitational waves in full 3D numerical relativity. We find that there exists an interesting regime in the parameter space of the wave configurations: a near-linear regime in which the amplitude of the wave is low enough that one expects the geometric deviation from...
[ { "created": "Wed, 17 Jan 1996 14:57:01 GMT", "version": "v1" }, { "created": "Thu, 24 Oct 1996 15:09:33 GMT", "version": "v2" } ]
2011-09-09
[ [ "Anninos", "Peter", "" ], [ "Masso", "Joan", "" ], [ "Seidel", "Edward", "" ], [ "Suen", "Wai-Mo", "" ], [ "Tobias", "Malcolm", "" ] ]
We report on a systematic study of the dynamics of gravitational waves in full 3D numerical relativity. We find that there exists an interesting regime in the parameter space of the wave configurations: a near-linear regime in which the amplitude of the wave is low enough that one expects the geometric deviation from f...
gr-qc/9712044
Jolien Creighton
Jolien D. E. Creighton (Caltech)
Listening for Ringing Black Holes
8 pages LaTeX, 1 eps figure included with epsfig, based on a talk given at the 7th Canadian Conference on General Relativity and Relativistic Astrophysics
null
null
null
gr-qc
null
The gravitational radiation produced by binary black holes during their inspiral, merger, and ringdown phases is a promising candidate for detection by the first or second generation of kilometer-scale interferometric gravitational wave antennas. Waveforms for the last phase, the quasinormal ringing, are well underst...
[ { "created": "Wed, 10 Dec 1997 00:25:32 GMT", "version": "v1" } ]
2007-05-23
[ [ "Creighton", "Jolien D. E.", "", "Caltech" ] ]
The gravitational radiation produced by binary black holes during their inspiral, merger, and ringdown phases is a promising candidate for detection by the first or second generation of kilometer-scale interferometric gravitational wave antennas. Waveforms for the last phase, the quasinormal ringing, are well understoo...
2403.07174
Debabrata Deb
Debabrata Deb, Manjari Bagchi, Sarmistha Banik
Exploring the Impact of Extra Dimensions on Neutron Star Structure and Equation of State
12 pages, 7 figures, 3 tables
null
null
null
gr-qc astro-ph.HE
http://creativecommons.org/licenses/by/4.0/
In this work, we explore the impact of higher dimensional spacetime on the stellar structure and thermodynamic properties of neutron stars. Utilizing the density-dependent relativistic hadron field theory, we introduce modifications to incorporate the influence of higher dimensionality, a novel approach not explored ...
[ { "created": "Mon, 11 Mar 2024 21:32:06 GMT", "version": "v1" } ]
2024-03-13
[ [ "Deb", "Debabrata", "" ], [ "Bagchi", "Manjari", "" ], [ "Banik", "Sarmistha", "" ] ]
In this work, we explore the impact of higher dimensional spacetime on the stellar structure and thermodynamic properties of neutron stars. Utilizing the density-dependent relativistic hadron field theory, we introduce modifications to incorporate the influence of higher dimensionality, a novel approach not explored in...
1910.07292
Stav Zalel
Fay Dowker, Nazireen Imambaccus, Amelia Owens, Rafael Sorkin, Stav Zalel
A manifestly covariant framework for causal set dynamics
32 pages, 12 figures
Class. Quantum Grav. 37 (2020) 085003
10.1088/1361-6382/ab719c
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a manifestly covariant framework for causal set dynamics. The framework is based on a structure, dubbed covtree, which is a partial order on certain sets of finite, unlabeled causal sets. We show that every infinite path in covtree corresponds to at least one infinite, unlabeled causal set. We show that tr...
[ { "created": "Wed, 16 Oct 2019 11:35:19 GMT", "version": "v1" }, { "created": "Wed, 25 Mar 2020 20:21:44 GMT", "version": "v2" } ]
2020-03-27
[ [ "Dowker", "Fay", "" ], [ "Imambaccus", "Nazireen", "" ], [ "Owens", "Amelia", "" ], [ "Sorkin", "Rafael", "" ], [ "Zalel", "Stav", "" ] ]
We propose a manifestly covariant framework for causal set dynamics. The framework is based on a structure, dubbed covtree, which is a partial order on certain sets of finite, unlabeled causal sets. We show that every infinite path in covtree corresponds to at least one infinite, unlabeled causal set. We show that tran...
1809.00618
David de Wolf Ph.D.
David A. de Wolf
Treatment of an accelerating observer via the special theory of relativity
16+ pages, 7 figures
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The clock time t' of an accelerating observer, simultaneous with the measured clock time t of an inertial observer,is easily established in special relativity (as proper time) by the well-known time-dilation formula for t'(t). In this work, a special-relativity formula t(t') for an initial observer's clock time t, si...
[ { "created": "Mon, 3 Sep 2018 14:43:30 GMT", "version": "v1" }, { "created": "Sun, 11 Nov 2018 09:51:48 GMT", "version": "v2" }, { "created": "Mon, 10 Jun 2019 13:05:58 GMT", "version": "v3" }, { "created": "Sun, 30 Jun 2019 13:04:30 GMT", "version": "v4" }, { "cr...
2019-08-27
[ [ "de Wolf", "David A.", "" ] ]
The clock time t' of an accelerating observer, simultaneous with the measured clock time t of an inertial observer,is easily established in special relativity (as proper time) by the well-known time-dilation formula for t'(t). In this work, a special-relativity formula t(t') for an initial observer's clock time t, simu...
0810.3399
Tao Mei
T. Mei
Negative kinetic energy term of general relativity and its removing
9 pages, no figure
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We first present a new Lagrangian of general relativity, which can be divided into kinetic energy term and potential energy term. Taking advantage of vierbein formalism, we reduce the kinetic energy term to a sum of five positive terms and one negative term. Some gauge conditions removing the negative kinetic energy ...
[ { "created": "Sun, 19 Oct 2008 13:48:39 GMT", "version": "v1" }, { "created": "Thu, 29 Jan 2009 12:57:02 GMT", "version": "v2" }, { "created": "Fri, 27 Mar 2009 13:46:24 GMT", "version": "v3" }, { "created": "Mon, 30 Mar 2009 02:38:36 GMT", "version": "v4" } ]
2009-03-30
[ [ "Mei", "T.", "" ] ]
We first present a new Lagrangian of general relativity, which can be divided into kinetic energy term and potential energy term. Taking advantage of vierbein formalism, we reduce the kinetic energy term to a sum of five positive terms and one negative term. Some gauge conditions removing the negative kinetic energy te...
2308.10052
I. V. Kanatchikov
I.V. Kanatchikov
The De Donder-Weyl Hamiltonian formulation of TEGR and its quantization
19pp
null
null
null
gr-qc math-ph math.MP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The De Donder-Weyl (DW) Hamiltonian theory of fields treats space and time variables on equal footing. Its quantization, called precanonical quantization, leads to a hypercomplex generalization of quantum formalism to field theory as it follows from the quantization of Poisson-Gerstenhaber brackets defined on differe...
[ { "created": "Sat, 19 Aug 2023 15:27:56 GMT", "version": "v1" } ]
2023-08-22
[ [ "Kanatchikov", "I. V.", "" ] ]
The De Donder-Weyl (DW) Hamiltonian theory of fields treats space and time variables on equal footing. Its quantization, called precanonical quantization, leads to a hypercomplex generalization of quantum formalism to field theory as it follows from the quantization of Poisson-Gerstenhaber brackets defined on different...
0903.2127
Guendelman Eduardo I
E.I. Guendelman
String Gas Shells, their Dual Radiation and Hedgehog Signature Control
7 pages
Phys.Lett.B677:71-73,2009
10.1016/j.physletb.2009.05.019
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We search for spherically symmetric, stationary solutions with a string gas shell as a source. The requirement of a uniform newtonian potential, or constancy of the 00 component of the metric, implies the existence of a "dual" radiation, which we argue can be interpreted as representing the virtual quantum fluctuatio...
[ { "created": "Thu, 12 Mar 2009 09:31:28 GMT", "version": "v1" } ]
2010-01-15
[ [ "Guendelman", "E. I.", "" ] ]
We search for spherically symmetric, stationary solutions with a string gas shell as a source. The requirement of a uniform newtonian potential, or constancy of the 00 component of the metric, implies the existence of a "dual" radiation, which we argue can be interpreted as representing the virtual quantum fluctuations...
gr-qc/9909090
null
A.A. Pomeransky and R.A. Sen'kov
Quadrupole interaction of relativistic quantum particle with external fields
8 pages, no figures
Phys.Lett. B468 (1999) 251-255
10.1016/S0370-2693(99)01234-4
null
gr-qc hep-th physics.acc-ph
null
We consider the motion of a spinning relativistic particle with an arbitrary value of spin in external electromagnetic and gravitational fields, to first order in the external field. We use the noncovariant description of spin. An explicit expression is obtained for the interaction of second order in spin. The value ...
[ { "created": "Thu, 30 Sep 1999 06:00:50 GMT", "version": "v1" } ]
2009-10-31
[ [ "Pomeransky", "A. A.", "" ], [ "Sen'kov", "R. A.", "" ] ]
We consider the motion of a spinning relativistic particle with an arbitrary value of spin in external electromagnetic and gravitational fields, to first order in the external field. We use the noncovariant description of spin. An explicit expression is obtained for the interaction of second order in spin. The value of...
2110.09077
Ming Zhang
Ming Zhang and Jie Jiang
Strong cosmic censorship in near-extremal Kerr-Sen-de Sitter spacetime
9 pages
null
10.1140/epjc/s10052-021-09753-x
null
gr-qc hep-th
http://creativecommons.org/licenses/by-nc-nd/4.0/
We first calculate equations of motion for particles in the Kerr-Sen-de Sitter black hole spacetime. Then in the eikonal regime, we analytically obtain the quasi-normal resonant modes of massless neutral scalar field perturbation and find its imaginary part to be characterized by the surface gravity of the near-extre...
[ { "created": "Mon, 18 Oct 2021 07:57:15 GMT", "version": "v1" } ]
2021-11-17
[ [ "Zhang", "Ming", "" ], [ "Jiang", "Jie", "" ] ]
We first calculate equations of motion for particles in the Kerr-Sen-de Sitter black hole spacetime. Then in the eikonal regime, we analytically obtain the quasi-normal resonant modes of massless neutral scalar field perturbation and find its imaginary part to be characterized by the surface gravity of the near-extrema...
2211.08753
Sarbari Guha Dr.
Uttaran Ghosh and Sarbari Guha
Vaidya-like exterior solution and formation of singularity in $f(R, T)$ theory of gravity
14 pages
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we study the gravitational collapse of a fluid ball undergoing dissipation in the form of heat flux, in the framework of $f(R,T)$ gravity. To apply the junction conditions in order to match the interior and the exterior spacetimes and analyze the dynamics of collapse, it is necessary to know the exteri...
[ { "created": "Wed, 16 Nov 2022 08:29:53 GMT", "version": "v1" }, { "created": "Thu, 17 Nov 2022 09:54:48 GMT", "version": "v2" }, { "created": "Sun, 11 Jun 2023 16:59:09 GMT", "version": "v3" } ]
2023-06-13
[ [ "Ghosh", "Uttaran", "" ], [ "Guha", "Sarbari", "" ] ]
In this paper, we study the gravitational collapse of a fluid ball undergoing dissipation in the form of heat flux, in the framework of $f(R,T)$ gravity. To apply the junction conditions in order to match the interior and the exterior spacetimes and analyze the dynamics of collapse, it is necessary to know the exterior...
1807.04060
Soumya Jana
Soumya Jana and Subhendra Mohanty (PRL Ahmedabad, India)
Constraints on $f(R)$ theories of gravity from GW170817
22 pages, 1 figure
Phys. Rev. D 99, 044056 (2019)
10.1103/PhysRevD.99.044056
null
gr-qc astro-ph.CO astro-ph.HE hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A novel constraint on $f(R)$ theories of gravity is obtained from the gravitational wave signal emitted from the binary neutron star merger event GW170817. The $f(R)$ theories possess an additional massive scalar degree of freedom apart from the massless spin-2 modes. The corresponding scalar field contributes an add...
[ { "created": "Wed, 11 Jul 2018 10:42:30 GMT", "version": "v1" }, { "created": "Fri, 1 Mar 2019 07:08:44 GMT", "version": "v2" } ]
2019-03-04
[ [ "Jana", "Soumya", "", "PRL Ahmedabad, India" ], [ "Mohanty", "Subhendra", "", "PRL Ahmedabad, India" ] ]
A novel constraint on $f(R)$ theories of gravity is obtained from the gravitational wave signal emitted from the binary neutron star merger event GW170817. The $f(R)$ theories possess an additional massive scalar degree of freedom apart from the massless spin-2 modes. The corresponding scalar field contributes an addit...
2111.09647
Reza Saffari
Solmaz Asgari, and Reza Saffari
Spacetime expansion in the presence of a background velocity field
25 pages, 12 figures, accepted for publication in European Physical Journal Plus (EPJP)
null
10.1140/epjp/s13360-021-02176-3
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this article, we introduce a new metric assuming an additional velocity-based term in a spacetime metric. Although the inclusion of this additional phrase can indicate that the Lorentz symmetry has broken, the results of null geodesics demonstrate that the amount of variation in the speed of light is considerably ...
[ { "created": "Thu, 18 Nov 2021 12:01:02 GMT", "version": "v1" } ]
2021-12-28
[ [ "Asgari", "Solmaz", "" ], [ "Saffari", "Reza", "" ] ]
In this article, we introduce a new metric assuming an additional velocity-based term in a spacetime metric. Although the inclusion of this additional phrase can indicate that the Lorentz symmetry has broken, the results of null geodesics demonstrate that the amount of variation in the speed of light is considerably sm...
1112.4663
Cosimo Bambi
Cosimo Bambi
Towards the use of the most massive black hole candidates in AGN to test the Kerr paradigm
12 pages, 6 figures. v2: some typos corrected
Phys.Rev.D85:043001,2012
10.1103/PhysRevD.85.043001
LMU-ASC-28-12
gr-qc astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The super-massive objects in galactic nuclei are thought to be the Kerr black holes predicted by General Relativity, although a definite proof of their actual nature is still lacking. The most massive objects in AGN ($M \sim 10^9 M_\odot$) seem to have a high radiative efficiency ($\eta \sim 0.4$) and a moderate mass...
[ { "created": "Tue, 20 Dec 2011 11:51:50 GMT", "version": "v1" }, { "created": "Fri, 6 Jan 2012 18:01:37 GMT", "version": "v2" } ]
2012-04-09
[ [ "Bambi", "Cosimo", "" ] ]
The super-massive objects in galactic nuclei are thought to be the Kerr black holes predicted by General Relativity, although a definite proof of their actual nature is still lacking. The most massive objects in AGN ($M \sim 10^9 M_\odot$) seem to have a high radiative efficiency ($\eta \sim 0.4$) and a moderate mass a...
gr-qc/9903036
Alejandro Jakubi
Luis P. Chimento, Alejandro S. Jakubi and Diego Pavon
Stability of inflationary solutions driven by a changing dissipative fluid
17 pages, LaTeX 2.09, 2 figures. To be published in Classical and Quantum Gravity
Class.Quant.Grav. 16 (1999) 1625-1635
10.1088/0264-9381/16/5/312
null
gr-qc
null
In this paper the second Lyapunov method is used to study the stability of the de Sitter phase of cosmic expansion when the source of the gravitational field is a viscous fluid. Different inflationary scenarios related with reheating and decay of mini-blackholes into radiation are investigated using an effective flui...
[ { "created": "Tue, 9 Mar 1999 19:38:45 GMT", "version": "v1" }, { "created": "Fri, 12 Mar 1999 01:10:08 GMT", "version": "v2" } ]
2009-10-31
[ [ "Chimento", "Luis P.", "" ], [ "Jakubi", "Alejandro S.", "" ], [ "Pavon", "Diego", "" ] ]
In this paper the second Lyapunov method is used to study the stability of the de Sitter phase of cosmic expansion when the source of the gravitational field is a viscous fluid. Different inflationary scenarios related with reheating and decay of mini-blackholes into radiation are investigated using an effective fluid ...
2301.07680
Miika Sarkkinen
Niko Jokela, K. Kajantie, Miika Sarkkinen
Gravitational wave memory in conformally flat spacetimes
27 pages, 1 figure; v2: a new paragraph added at the beginning of Sec. 3, reference to Fig. 1 added in the text, typos corrected, published version
JHEP05 (2023) 055
10.1007/JHEP05(2023)055
HIP-2023-3/TH
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the gravitational wave memory effect in spacetimes related to flat space by a conformal transformation. The discussion is general but the gravitational wave length scale is assumed to be small compared with the background curvature radius. The general formulas are applied to Friedmann-Robertson-Walker metric...
[ { "created": "Wed, 18 Jan 2023 17:59:25 GMT", "version": "v1" }, { "created": "Wed, 10 May 2023 11:32:53 GMT", "version": "v2" } ]
2023-05-11
[ [ "Jokela", "Niko", "" ], [ "Kajantie", "K.", "" ], [ "Sarkkinen", "Miika", "" ] ]
We study the gravitational wave memory effect in spacetimes related to flat space by a conformal transformation. The discussion is general but the gravitational wave length scale is assumed to be small compared with the background curvature radius. The general formulas are applied to Friedmann-Robertson-Walker metrics ...
1310.0711
Mariafelicia De Laurentis Professor
Mariafelicia De Laurentis and Ivan De Martino
Probing the physical and mathematical structure of $f(R)$ gravity by PSR $J0348+0432$
6 pages, 1 figure, accepted in International Journal of Geometric Methods in Modern Physics
null
10.1142/S0219887815500401
null
gr-qc astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
There are several approaches to extend General Relativity in order to explain the phenomena related to the Dark Matter and Dark Energy. These theories, generally called Extended Theories of Gravity, can be tested using observations coming from relativistic binary systems as PSR $J0348+0432$. Using a class of analytic...
[ { "created": "Wed, 2 Oct 2013 14:11:50 GMT", "version": "v1" }, { "created": "Fri, 21 Feb 2014 11:39:05 GMT", "version": "v2" }, { "created": "Wed, 12 Nov 2014 12:07:50 GMT", "version": "v3" } ]
2015-06-24
[ [ "De Laurentis", "Mariafelicia", "" ], [ "De Martino", "Ivan", "" ] ]
There are several approaches to extend General Relativity in order to explain the phenomena related to the Dark Matter and Dark Energy. These theories, generally called Extended Theories of Gravity, can be tested using observations coming from relativistic binary systems as PSR $J0348+0432$. Using a class of analytical...
2207.05117
Marcus Reitz
Marcus Reitz, D\'aniel N\'emeth, Damodar Rajbhandari, Andrzej G\"orlich, Jakub Gizbert-Studnicki
Generalised spectral dimensions in non-perturbative quantum gravity
35 pages, 18 figures
Class. Quantum Grav. 40 (2023) 125003
10.1088/1361-6382/acd0fc
null
gr-qc hep-th
http://creativecommons.org/licenses/by/4.0/
The seemingly universal phenomenon of scale-dependent effective dimensions in non-perturbative theories of quantum gravity has been shown to be a potential source of quantum gravity phenomenology. The scale-dependent effective dimension from quantum gravity has only been considered for scalar fields. It is however po...
[ { "created": "Mon, 11 Jul 2022 18:22:39 GMT", "version": "v1" }, { "created": "Fri, 18 Nov 2022 10:22:36 GMT", "version": "v2" } ]
2023-05-16
[ [ "Reitz", "Marcus", "" ], [ "Németh", "Dániel", "" ], [ "Rajbhandari", "Damodar", "" ], [ "Görlich", "Andrzej", "" ], [ "Gizbert-Studnicki", "Jakub", "" ] ]
The seemingly universal phenomenon of scale-dependent effective dimensions in non-perturbative theories of quantum gravity has been shown to be a potential source of quantum gravity phenomenology. The scale-dependent effective dimension from quantum gravity has only been considered for scalar fields. It is however poss...
gr-qc/9507052
Jolien Creighton
Jolien Creighton and Robert Mann
Quailocal Formalism for Dilaton Gravity with Yang-Mills Fields
5 pages. Uses AMS-TeX preprint style. Submitted to the proceedings of the 6th Canadian Conference on General Relativity and Relativistic Astrophysics
null
null
null
gr-qc
null
We present a quasilocal formalism, based on the one proposed by Brown and York, for dilaton gravity with Yang-Mills fields. For solutions possessing sufficient symmetry, we define conserved quantities such as mass, angular momentum, and charge. We also present a micro-canonical action and use it to arrive at a quasil...
[ { "created": "Wed, 26 Jul 1995 17:31:38 GMT", "version": "v1" } ]
2007-05-23
[ [ "Creighton", "Jolien", "" ], [ "Mann", "Robert", "" ] ]
We present a quasilocal formalism, based on the one proposed by Brown and York, for dilaton gravity with Yang-Mills fields. For solutions possessing sufficient symmetry, we define conserved quantities such as mass, angular momentum, and charge. We also present a micro-canonical action and use it to arrive at a quasiloc...
gr-qc/9802011
Mark E. Rupright
M. E. Rupright, A. M. Abrahams, L. Rezzolla
Cauchy-perturbative matching and outer boundary conditions I: Methods and tests
13 pages, 6 figures, RevTeX
Phys.Rev. D58 (1998) 044005
10.1103/PhysRevD.58.044005
TAR-064-UNC
gr-qc
null
We present a new method of extracting gravitational radiation from three-dimensional numerical relativity codes and providing outer boundary conditions. Our approach matches the solution of a Cauchy evolution of Einstein's equations to a set of one-dimensional linear wave equations on a curved background. We illustra...
[ { "created": "Tue, 3 Feb 1998 19:23:54 GMT", "version": "v1" } ]
2009-10-31
[ [ "Rupright", "M. E.", "" ], [ "Abrahams", "A. M.", "" ], [ "Rezzolla", "L.", "" ] ]
We present a new method of extracting gravitational radiation from three-dimensional numerical relativity codes and providing outer boundary conditions. Our approach matches the solution of a Cauchy evolution of Einstein's equations to a set of one-dimensional linear wave equations on a curved background. We illustrate...
1506.04569
Janilo Santos
Noelia S. Santos and Janilo Santos
The virial theorem in Eddington-Born-Infeld gravity
15 pages; no figures. Improved version, some comments and References added. Submitted to publication. arXiv admin note: text overlap with arXiv:0710.0966, arXiv:1212.5817 by other authors
JCAP 12 (2015) 002
10.1088/1475-7516/2015/12/002
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider the possibility that the Eddington-Born-Infeld (EBI) modified gravity provides an alternative explanation for the mass discrepancy in clusters of galaxies. For this purpose we derive the modified Einstein field equations, finding an additional "geometrical mass" term which provides an effective contributi...
[ { "created": "Mon, 15 Jun 2015 12:39:00 GMT", "version": "v1" }, { "created": "Wed, 19 Aug 2015 18:18:53 GMT", "version": "v2" }, { "created": "Fri, 28 Aug 2015 22:12:27 GMT", "version": "v3" }, { "created": "Wed, 28 Oct 2015 15:24:11 GMT", "version": "v4" } ]
2015-12-07
[ [ "Santos", "Noelia S.", "" ], [ "Santos", "Janilo", "" ] ]
We consider the possibility that the Eddington-Born-Infeld (EBI) modified gravity provides an alternative explanation for the mass discrepancy in clusters of galaxies. For this purpose we derive the modified Einstein field equations, finding an additional "geometrical mass" term which provides an effective contribution...
1508.01614
Arman Akbarian
Arman Akbarian, Matthew W. Choptuik
Black hole critical behaviour with the generalized BSSN formulation
Minor revisions in response to referee's comments
Phys. Rev. D 92, 084037 (2015)
10.1103/PhysRevD.92.084037
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The development of hyperbolic formulations of Einstein's equations has revolutionized our ability to perform long-time, stable, accurate numerical simulations of strong field gravitational phenomena. However, hyperbolic methods have seen relatively little application in one area of interest, type II critical collapse...
[ { "created": "Fri, 7 Aug 2015 06:04:36 GMT", "version": "v1" }, { "created": "Sun, 18 Oct 2015 01:27:41 GMT", "version": "v2" } ]
2015-10-21
[ [ "Akbarian", "Arman", "" ], [ "Choptuik", "Matthew W.", "" ] ]
The development of hyperbolic formulations of Einstein's equations has revolutionized our ability to perform long-time, stable, accurate numerical simulations of strong field gravitational phenomena. However, hyperbolic methods have seen relatively little application in one area of interest, type II critical collapse, ...
1805.05264
Larry Ford
H.S. Vieira, L.H. Ford, and V.B. Bezerra
Spacetime geometry fluctuations and geodesic deviation
27 pages, 3 figures
Phys. Rev. D 98, 086001 (2018)
10.1103/PhysRevD.98.086001
null
gr-qc hep-th quant-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The quantum fluctuations of the geodesic deviation equation in a flat background spacetime are discussed. We calculate the resulting mean squared fluctuations in the relative velocity and separation of test particles. The effect of these quantum fluctuations of the spacetime geometry is given in terms of the Riemann ...
[ { "created": "Mon, 14 May 2018 16:29:07 GMT", "version": "v1" } ]
2018-10-10
[ [ "Vieira", "H. S.", "" ], [ "Ford", "L. H.", "" ], [ "Bezerra", "V. B.", "" ] ]
The quantum fluctuations of the geodesic deviation equation in a flat background spacetime are discussed. We calculate the resulting mean squared fluctuations in the relative velocity and separation of test particles. The effect of these quantum fluctuations of the spacetime geometry is given in terms of the Riemann te...
2206.11870
Erik Aurell
Erik Aurell
The double doors of the horizon
5 pages, 57 references. The text of the revised version is partly reorganized, and additional references are cited
null
null
null
gr-qc quant-ph
http://creativecommons.org/licenses/by/4.0/
In statistical mechanics entropy is a measure of disorder obeying Boltzmann's formula $S=\log{\cal N}$, where ${\cal N}$ is the accessible phase space volume. In black hole thermodynamics one associates to a black hole an entropy Bekenstein-Hawking $S_{BH}$. It is well known that $S_{BH}$ is very large for astrophysi...
[ { "created": "Wed, 22 Jun 2022 17:49:53 GMT", "version": "v1" }, { "created": "Wed, 10 Aug 2022 13:25:34 GMT", "version": "v2" } ]
2022-08-11
[ [ "Aurell", "Erik", "" ] ]
In statistical mechanics entropy is a measure of disorder obeying Boltzmann's formula $S=\log{\cal N}$, where ${\cal N}$ is the accessible phase space volume. In black hole thermodynamics one associates to a black hole an entropy Bekenstein-Hawking $S_{BH}$. It is well known that $S_{BH}$ is very large for astrophysica...
gr-qc/9810052
Aleksandar Bogojevic
Aleksandar Bogojevic (Institute of Physics) and Dejan Stojkovic (Case Western Reserve University)
Black Holes Without Singularities
5 pages, Latex 2e, 1 figure, Lectures given at 11th Yugoslav Symposium on Nuclear and Particle Physics, Studenica, September 1998
null
null
IP-HET-98/24
gr-qc
null
We study the properties of a completely integrable deformation of the CGHS dilaton gravity model in two dimensions. The solution is shown to represent a singularity free black hole that at large distances asymptoticaly joins to the CGHS solution.
[ { "created": "Thu, 15 Oct 1998 22:45:31 GMT", "version": "v1" } ]
2007-05-23
[ [ "Bogojevic", "Aleksandar", "", "Institute of Physics" ], [ "Stojkovic", "Dejan", "", "Case\n Western Reserve University" ] ]
We study the properties of a completely integrable deformation of the CGHS dilaton gravity model in two dimensions. The solution is shown to represent a singularity free black hole that at large distances asymptoticaly joins to the CGHS solution.
2402.06096
Xiaoming Bi
Xiaoming Bi, Zhongkai Guo, Xiaobo Zou, Yong Huang, Peijia Li, Jianfeng Cao, Lue Chen, Wenlin Tang and Yun Kau Lau
Doppler Tracking Data of Martian Mission Tianwen-I and Upper Limit of Stochastic Gravitational Wave Background
10 pages, 8 figures
null
null
null
gr-qc astro-ph.EP astro-ph.IM physics.space-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Two way ranging data for spacecraft tracking of China's first Martian mission Tianwen-I is analysed. Shortly before the spacecraft entered the Mars parking orbit, the two way coherent microwave link between the spacecraft and the Earth resembles a long arm gravitational wave interferometer, with both the spacecraft a...
[ { "created": "Thu, 8 Feb 2024 23:11:16 GMT", "version": "v1" } ]
2024-02-12
[ [ "Bi", "Xiaoming", "" ], [ "Guo", "Zhongkai", "" ], [ "Zou", "Xiaobo", "" ], [ "Huang", "Yong", "" ], [ "Li", "Peijia", "" ], [ "Cao", "Jianfeng", "" ], [ "Chen", "Lue", "" ], [ "Tang", "Wenlin",...
Two way ranging data for spacecraft tracking of China's first Martian mission Tianwen-I is analysed. Shortly before the spacecraft entered the Mars parking orbit, the two way coherent microwave link between the spacecraft and the Earth resembles a long arm gravitational wave interferometer, with both the spacecraft and...
gr-qc/0212035
Yuki Uchida
Daisuke Ida, Yuki Uchida and Yoshiyuki Morisawa
The scalar perturbation of the higher-dimensional rotating black holes
16 pages, 7 figures, revised version
Phys.Rev. D67 (2003) 084019
10.1103/PhysRevD.67.084019
null
gr-qc hep-th
null
The massless scalar field in the higher-dimensional Kerr black hole (Myers- Perry solution with a single rotation axis) has been investigated. It has been shown that the field equation is separable in arbitrary dimensions. The quasi-normal modes of the scalar field have been searched in five dimensions using the cont...
[ { "created": "Sun, 8 Dec 2002 07:23:44 GMT", "version": "v1" }, { "created": "Mon, 13 Jan 2003 08:23:42 GMT", "version": "v2" } ]
2009-11-07
[ [ "Ida", "Daisuke", "" ], [ "Uchida", "Yuki", "" ], [ "Morisawa", "Yoshiyuki", "" ] ]
The massless scalar field in the higher-dimensional Kerr black hole (Myers- Perry solution with a single rotation axis) has been investigated. It has been shown that the field equation is separable in arbitrary dimensions. The quasi-normal modes of the scalar field have been searched in five dimensions using the contin...
2208.04051
Valerio Faraoni
Valerio Faraoni, Serena Giardino, Andrea Giusti, and Robert Vanderwee
Scalar field as a perfect fluid: thermodynamics of minimally coupled scalars and Einstein frame scalar-tensor gravity
19 pages, latex
null
10.1140/epjc/s10052-023-11186-7
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We revisit the analogy between a minimally coupled scalar field in general relativity and a perfect fluid, correcting previous identifications of effective temperature and chemical potential. This provides a useful complementary picture for the first-order thermodynamics of scalar-tensor gravity, paving the way for t...
[ { "created": "Mon, 8 Aug 2022 10:49:03 GMT", "version": "v1" } ]
2023-02-01
[ [ "Faraoni", "Valerio", "" ], [ "Giardino", "Serena", "" ], [ "Giusti", "Andrea", "" ], [ "Vanderwee", "Robert", "" ] ]
We revisit the analogy between a minimally coupled scalar field in general relativity and a perfect fluid, correcting previous identifications of effective temperature and chemical potential. This provides a useful complementary picture for the first-order thermodynamics of scalar-tensor gravity, paving the way for the...
1808.02751
Kimet Jusufi
Kimet Jusufi, Ayan Banerjee, Galin Gyulchev, Muhammed Amir
Distinguishing rotating naked singularities from Kerr-like wormholes by their deflection angles of massive particles
24 pages, 3 figures, accepted for publication in European Physical Journal C
Eur. Phys. J. C (2019) 79:28
10.1140/epjc/s10052-019-6557-2
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the gravitational deflection of relativistic massive particles by Janis-Newman-Winicour (JNW) spacetimes (also known as a rotating source with a surface-like naked singularity), and a rotating Kerr-like wormholes. Based on the recent article [K. Jusufi, Phys. Rev. D 98, 064017 (2018)], we extend some of thes...
[ { "created": "Wed, 8 Aug 2018 13:15:17 GMT", "version": "v1" }, { "created": "Thu, 3 Jan 2019 16:40:52 GMT", "version": "v2" } ]
2019-01-17
[ [ "Jusufi", "Kimet", "" ], [ "Banerjee", "Ayan", "" ], [ "Gyulchev", "Galin", "" ], [ "Amir", "Muhammed", "" ] ]
We study the gravitational deflection of relativistic massive particles by Janis-Newman-Winicour (JNW) spacetimes (also known as a rotating source with a surface-like naked singularity), and a rotating Kerr-like wormholes. Based on the recent article [K. Jusufi, Phys. Rev. D 98, 064017 (2018)], we extend some of these ...
2012.12128
LSC P&P Committee
The LIGO Scientific Collaboration and the Virgo Collaboration: R. Abbott, T. D. Abbott, S. Abraham, F. Acernese, K. Ackley, A. Adams, C. Adams, R. X. Adhikari, V. B. Adya, C. Affeldt, D. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, K. M. Aleman, G. Allen, A. Allocca,...
All-sky search in early O3 LIGO data for continuous gravitational-wave signals from unknown neutron stars in binary systems
23 pages, 12 figures, 7 tables
Phys. Rev. D 103, 064017 (2021)
10.1103/PhysRevD.103.064017
LIGO-P2000298
gr-qc astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Rapidly spinning neutron stars are promising sources of persistent, continuous gravitational waves. Detecting such a signal would allow probing of the physical properties of matter under extreme conditions. A significant fraction of the known pulsar population belongs to binary systems. Searching for unknown neutron ...
[ { "created": "Tue, 22 Dec 2020 16:06:23 GMT", "version": "v1" }, { "created": "Fri, 19 Mar 2021 14:21:37 GMT", "version": "v2" } ]
2021-03-22
[ [ "The LIGO Scientific Collaboration", "", "" ], [ "the Virgo Collaboration", "", "" ], [ "Abbott", "R.", "" ], [ "Abbott", "T. D.", "" ], [ "Abraham", "S.", "" ], [ "Acernese", "F.", "" ], [ "Ackley", "K.", ...
Rapidly spinning neutron stars are promising sources of persistent, continuous gravitational waves. Detecting such a signal would allow probing of the physical properties of matter under extreme conditions. A significant fraction of the known pulsar population belongs to binary systems. Searching for unknown neutron st...
gr-qc/0407096
Hossein Shojaie
Hossein Shojaie, Mehrdad Farhoudi
A cosmology with variable c
10 pages
Can.J.Phys.84:933-944,2006
10.1139/P06-070
null
gr-qc astro-ph
null
A new varying-$c$ cosmological model constructed using two additional assumptions, which was introduced in our previous work, is briefly reviewed and the dynamic equation of the model is derived distinctly from a semi-Newtonian approach. The results of this model, using a $\Lambda$ term and an extra energy-momentum t...
[ { "created": "Mon, 26 Jul 2004 14:24:52 GMT", "version": "v1" }, { "created": "Wed, 29 Nov 2006 20:02:25 GMT", "version": "v2" } ]
2010-09-28
[ [ "Shojaie", "Hossein", "" ], [ "Farhoudi", "Mehrdad", "" ] ]
A new varying-$c$ cosmological model constructed using two additional assumptions, which was introduced in our previous work, is briefly reviewed and the dynamic equation of the model is derived distinctly from a semi-Newtonian approach. The results of this model, using a $\Lambda$ term and an extra energy-momentum ten...
gr-qc/0401079
Muhammad Sharif
M. Sharif and T. Iqbal
Non-Static Spherically Symmetric Perfect Fluid Solutions
null
Chin.J.Phys. 40 (2002) 242-250
null
null
gr-qc
null
We investigate solutions of Einstein field equations for the non-static spherically symmetric perfect fluid case using different equations of state. The properties of an exact spherically symmetric perfect fluid solutions are obtained which contain shear. We obtain three different solutions out of these one turns out...
[ { "created": "Mon, 19 Jan 2004 06:01:56 GMT", "version": "v1" } ]
2007-05-23
[ [ "Sharif", "M.", "" ], [ "Iqbal", "T.", "" ] ]
We investigate solutions of Einstein field equations for the non-static spherically symmetric perfect fluid case using different equations of state. The properties of an exact spherically symmetric perfect fluid solutions are obtained which contain shear. We obtain three different solutions out of these one turns out t...
1103.3679
Jose Geraldo Pereira
J. P. Beltran Almeida, C. S. O. Mayor, J. G. Pereira
de Sitter relativity: a natural scenario for an evolving Lambda
V1: 11 pages. V2: Presentation changes, new discussion added, 13 pages
Grav. Cosm. 18 (2012) 181-187
10.1134/S0202289312030012
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The dispersion relation of de Sitter special relativity is obtained in a simple and compact form, which is formally similar to the dispersion relation of ordinary special relativity. It is manifestly invariant under change of scale of mass, energy and momentum, and can thus be applied at any energy scale. When applie...
[ { "created": "Fri, 18 Mar 2011 18:00:58 GMT", "version": "v1" }, { "created": "Thu, 4 Aug 2011 18:13:29 GMT", "version": "v2" } ]
2015-03-19
[ [ "Almeida", "J. P. Beltran", "" ], [ "Mayor", "C. S. O.", "" ], [ "Pereira", "J. G.", "" ] ]
The dispersion relation of de Sitter special relativity is obtained in a simple and compact form, which is formally similar to the dispersion relation of ordinary special relativity. It is manifestly invariant under change of scale of mass, energy and momentum, and can thus be applied at any energy scale. When applied ...
gr-qc/9211013
null
Daniel Cangemi, Martin Leblanc and Robert B. Mann
Gauge Formulation of the Spinning Black Hole in (2+1)-Dimensional Anti-de Sitter Space
10 pages
Phys.Rev. D48 (1993) 3606-3610
10.1103/PhysRevD.48.3606
CTP#2162, WATPHYS-TH92/09
gr-qc hep-th
null
We compute the group element of SO(2,2) associated with the spinning black hole found by Ba\~nados, Teitelboim and Zanelli in (2+1)-dimensional anti-de Sitter space-time. We show that their metric is built with SO(2,2) gauge invariant quantities and satisfies Einstein's equations with negative cosmological constant e...
[ { "created": "Mon, 9 Nov 1992 21:55:35 GMT", "version": "v1" } ]
2009-10-22
[ [ "Cangemi", "Daniel", "" ], [ "Leblanc", "Martin", "" ], [ "Mann", "Robert B.", "" ] ]
We compute the group element of SO(2,2) associated with the spinning black hole found by Ba\~nados, Teitelboim and Zanelli in (2+1)-dimensional anti-de Sitter space-time. We show that their metric is built with SO(2,2) gauge invariant quantities and satisfies Einstein's equations with negative cosmological constant eve...
0804.3584
Luis Herrera
L. Herrera, A. Di Prisco, E. Fuenmayor, O. Troconis
Dynamics of viscous dissipative gravitational collapse: A full causal approach
22 pages Latex. To appear in Int. J. Mod. Phys. D. Typos corrected
Int.J.Mod.Phys.D18:129-145,2009
10.1142/S0218271809014285
null
gr-qc astro-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Misner and Sharp approach to the study of gravitational collapse is extended to the viscous dissipative case in, both, the streaming out and the diffusion approximations. The dynamical equation is then coupled to causal transport equations for the heat flux, the shear and the bulk viscosity, in the context of Isr...
[ { "created": "Tue, 22 Apr 2008 18:50:26 GMT", "version": "v1" }, { "created": "Mon, 16 Mar 2009 10:05:26 GMT", "version": "v2" } ]
2009-03-24
[ [ "Herrera", "L.", "" ], [ "Di Prisco", "A.", "" ], [ "Fuenmayor", "E.", "" ], [ "Troconis", "O.", "" ] ]
The Misner and Sharp approach to the study of gravitational collapse is extended to the viscous dissipative case in, both, the streaming out and the diffusion approximations. The dynamical equation is then coupled to causal transport equations for the heat flux, the shear and the bulk viscosity, in the context of Israe...
2004.02934
Eric D. Carlson
Sarah B. Fisher and Eric D. Carlson
Response to Comment on "Reexamining $f(R,T)$ Gravity''
null
null
10.1103/PhysRevD.101.108502
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Harko and Moraes claim that in $f(R,T)$ gravity with $f(R,T)=f_1(R)+f_2(T)$, the term $f_2(T)$ cannot be incorporated in the matter Lagrangian ${\cal L}_m$. A careful examination of their Comment finds that they have made several dubious assumptions without indicating any errors in our work. Most notably, they have u...
[ { "created": "Mon, 6 Apr 2020 18:50:33 GMT", "version": "v1" } ]
2020-06-24
[ [ "Fisher", "Sarah B.", "" ], [ "Carlson", "Eric D.", "" ] ]
Harko and Moraes claim that in $f(R,T)$ gravity with $f(R,T)=f_1(R)+f_2(T)$, the term $f_2(T)$ cannot be incorporated in the matter Lagrangian ${\cal L}_m$. A careful examination of their Comment finds that they have made several dubious assumptions without indicating any errors in our work. Most notably, they have unj...
2405.10671
Hyat Huang
Carlos Herdeiro, Hyat Huang, Jutta Kunz and Eugen Radu
Einstein-(complex)-Maxwell static boson stars in AdS
13 pages, 2 figures
null
null
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider a model with two real Maxwell fields (or equivalently, a complex Maxwell field) minimally coupled to Einsteins gravity with a negative cosmological constant in four spacetime dimensions. Assuming a specific harmonic dependence of the vector fields, we show the existence of asymptotically anti-de Sitter (A...
[ { "created": "Fri, 17 May 2024 10:04:11 GMT", "version": "v1" } ]
2024-05-20
[ [ "Herdeiro", "Carlos", "" ], [ "Huang", "Hyat", "" ], [ "Kunz", "Jutta", "" ], [ "Radu", "Eugen", "" ] ]
We consider a model with two real Maxwell fields (or equivalently, a complex Maxwell field) minimally coupled to Einsteins gravity with a negative cosmological constant in four spacetime dimensions. Assuming a specific harmonic dependence of the vector fields, we show the existence of asymptotically anti-de Sitter (AdS...
1509.00706
Rathin Adhikari
Vikram Soni, Naresh Dadhich, Rathin Adhikari
The cosmological constant from the zero point energy of compact dimensions
6 pages
null
null
null
gr-qc astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider extra compact dimensions as the origin of a cosmological universal energy density in the regular dimensions, with only graviton fields propagating in the compact space dimensions. The quantum zero point energy originating from the finite size boundary condition in the compact dimensions can produce a cons...
[ { "created": "Wed, 2 Sep 2015 13:55:40 GMT", "version": "v1" } ]
2015-09-03
[ [ "Soni", "Vikram", "" ], [ "Dadhich", "Naresh", "" ], [ "Adhikari", "Rathin", "" ] ]
We consider extra compact dimensions as the origin of a cosmological universal energy density in the regular dimensions, with only graviton fields propagating in the compact space dimensions. The quantum zero point energy originating from the finite size boundary condition in the compact dimensions can produce a consta...
2006.10068
Marius Oltean
Marius Oltean, Hossein Bazrafshan Moghaddam, Richard J. Epp
Energy of cosmological spacetimes and perturbations: a quasilocal approach
v1: 28 pages, 3 figures; v2: 30 pages. References and comments added; v3: 35 pages. New subsection (IV A) added
Class. Quantum Grav. 38, 085012 (2021)
10.1088/1361-6382/abeae3
null
gr-qc astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Quasilocal definitions of stress-energy-momentum -- that is, in the form of boundary densities (rather than local volume densities) -- have proven generally very useful in formulating and applying conservation laws in general relativity. In this paper, we present a detailed application of such definitions to cosmolog...
[ { "created": "Wed, 17 Jun 2020 18:00:05 GMT", "version": "v1" }, { "created": "Wed, 28 Oct 2020 17:20:21 GMT", "version": "v2" }, { "created": "Tue, 16 Feb 2021 13:07:55 GMT", "version": "v3" } ]
2021-04-27
[ [ "Oltean", "Marius", "" ], [ "Moghaddam", "Hossein Bazrafshan", "" ], [ "Epp", "Richard J.", "" ] ]
Quasilocal definitions of stress-energy-momentum -- that is, in the form of boundary densities (rather than local volume densities) -- have proven generally very useful in formulating and applying conservation laws in general relativity. In this paper, we present a detailed application of such definitions to cosmology,...
1411.2705
Seyen Kouwn
Seyen Kouwn, O-Kab Kwon and Phillial Oh
Large Scale Suppression of Scalar Power on a Spatial Condensation
20 pages, 3 figures. Revised version, accepted for publication in PRD
Phys. Rev. D 91, 063521 (2015)
10.1103/PhysRevD.91.063521
null
gr-qc astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Suppression of the scalar power spectrum on large scales is one way to reconcile the tension between Planck and BICEP2 data. This suppression can occur by introducing a phase transition from the fast-roll phase to the slow-roll phase in a single field inflation model. In this paper we consider a deformed single field...
[ { "created": "Tue, 11 Nov 2014 05:46:20 GMT", "version": "v1" }, { "created": "Wed, 4 Mar 2015 01:23:09 GMT", "version": "v2" } ]
2015-03-25
[ [ "Kouwn", "Seyen", "" ], [ "Kwon", "O-Kab", "" ], [ "Oh", "Phillial", "" ] ]
Suppression of the scalar power spectrum on large scales is one way to reconcile the tension between Planck and BICEP2 data. This suppression can occur by introducing a phase transition from the fast-roll phase to the slow-roll phase in a single field inflation model. In this paper we consider a deformed single field i...
gr-qc/9509046
Andrew Chamblin
Andrew Chamblin
Topology and Causal Structure
uuencoded file containing slightly revised and improved version of 20 pages LaTeX with four figures, expanded version of a talk presented at the 6th Canadian Conference on General Relativity and Relativistic Astrophysics
null
null
DAMTP R95/39
gr-qc
null
We investigate the causal structure of spacetimes $(M, g)$ for which the metric $g$ is singular on a set of points.
[ { "created": "Mon, 25 Sep 1995 20:02:42 GMT", "version": "v1" }, { "created": "Wed, 3 Jul 1996 23:21:34 GMT", "version": "v2" } ]
2008-02-03
[ [ "Chamblin", "Andrew", "" ] ]
We investigate the causal structure of spacetimes $(M, g)$ for which the metric $g$ is singular on a set of points.
2304.01695
Peng Zhao
Peng Zhao, David Hilditch, and Juan A. Valiente Kroon
Trapped surface formation for the Einstein-Scalar system
null
null
null
null
gr-qc
http://creativecommons.org/licenses/by/4.0/
We consider the formation of trapped surfaces in the evolution of the Einstein-scalar field system without symmetries. To this end, we follow An's strategy to analyse the formation of trapped surfaces in vacuum and for the Einstein-Maxwell system. Accordingly, we set up a characteristic initial value problem ...
[ { "created": "Tue, 4 Apr 2023 10:48:35 GMT", "version": "v1" } ]
2023-04-05
[ [ "Zhao", "Peng", "" ], [ "Hilditch", "David", "" ], [ "Kroon", "Juan A. Valiente", "" ] ]
We consider the formation of trapped surfaces in the evolution of the Einstein-scalar field system without symmetries. To this end, we follow An's strategy to analyse the formation of trapped surfaces in vacuum and for the Einstein-Maxwell system. Accordingly, we set up a characteristic initial value problem (CIVP) for...
1001.3631
Gaurav Khanna
Gaurav Khanna, Justin McKennon
Numerical modeling of gravitational wave sources accelerated by OpenCL
15 pages, 4 figures, published in (Elsevier) Computer Physics Communications
Comput.Phys.Commun.181:1605-1611,2010
10.1016/j.cpc.2010.05.014
null
gr-qc physics.comp-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this work, we make use of the OpenCL framework to accelerate an EMRI modeling application using the hardware accelerators -- Cell BE and Tesla CUDA GPU. We describe these compute technologies and our parallelization approach in detail, present our performance results, and then compare them with those from our prev...
[ { "created": "Wed, 20 Jan 2010 16:10:28 GMT", "version": "v1" }, { "created": "Thu, 3 Jun 2010 14:17:08 GMT", "version": "v2" }, { "created": "Tue, 4 Oct 2011 00:56:05 GMT", "version": "v3" } ]
2011-10-05
[ [ "Khanna", "Gaurav", "" ], [ "McKennon", "Justin", "" ] ]
In this work, we make use of the OpenCL framework to accelerate an EMRI modeling application using the hardware accelerators -- Cell BE and Tesla CUDA GPU. We describe these compute technologies and our parallelization approach in detail, present our performance results, and then compare them with those from our previo...
1705.03772
Etera R. Livine
Jibril Ben Achour, Etera R. Livine
The Thiemann Complexifier and the CVH algebra for Classical and Quantum FLRW Cosmology
38 pages; Corrected version accepted for publication in PRD with clarifications on role of Immirzi parameter and minimal volume
Phys. Rev. D 96, 066025 (2017)
10.1103/PhysRevD.96.066025
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In the context of Loop Quantum Gravity (LQG), we study the fate of Thiemann complexifier in homogeneous and isotropic FRW cosmology. The complexifier is the dilatation operator acting on the canonical phase space for gravity and generates the canonical transformations shifting the Barbero-Immirzi parameter. We focus ...
[ { "created": "Wed, 10 May 2017 13:54:50 GMT", "version": "v1" }, { "created": "Sat, 26 Aug 2017 14:54:33 GMT", "version": "v2" } ]
2017-09-27
[ [ "Achour", "Jibril Ben", "" ], [ "Livine", "Etera R.", "" ] ]
In the context of Loop Quantum Gravity (LQG), we study the fate of Thiemann complexifier in homogeneous and isotropic FRW cosmology. The complexifier is the dilatation operator acting on the canonical phase space for gravity and generates the canonical transformations shifting the Barbero-Immirzi parameter. We focus on...
2008.01154
Neil Turok
Job Feldbrugge and Neil Turok
Gravitational lensing of binary systems in wave optics
5 pages, 4 figures
null
null
null
gr-qc astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present the first detailed computations of wave optics effects in the gravitational lensing of binary systems. The field is conceptually rich, combining the caustic singularities produced in classical gravitational lensing with quantum (wave) interference effects. New techniques have enabled us to overcome previou...
[ { "created": "Mon, 3 Aug 2020 19:44:16 GMT", "version": "v1" } ]
2020-08-06
[ [ "Feldbrugge", "Job", "" ], [ "Turok", "Neil", "" ] ]
We present the first detailed computations of wave optics effects in the gravitational lensing of binary systems. The field is conceptually rich, combining the caustic singularities produced in classical gravitational lensing with quantum (wave) interference effects. New techniques have enabled us to overcome previous ...
1507.04212
Shahram Jalalzadeh
T. Rostami, S. Jalalzadeh and P.V. Moniz
Quantum cosmological intertwining: Factor ordering and boundary conditions from hidden symmetries
13 pages, no figure, to appear in Phys. Rev. D
null
10.1103/PhysRevD.92.023526
null
gr-qc math-ph math.MP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We explore the implications of hidden symmetries present in a particular quantum cosmological setting, extending the results reported in \cite{10,11}. In more detail, our case study is constituted by a spatially closed Friedmann-Lema\^{\i}tre-Robertson-Walker universe, in the presence of a conformally coupled scalar ...
[ { "created": "Wed, 15 Jul 2015 13:35:28 GMT", "version": "v1" } ]
2015-08-06
[ [ "Rostami", "T.", "" ], [ "Jalalzadeh", "S.", "" ], [ "Moniz", "P. V.", "" ] ]
We explore the implications of hidden symmetries present in a particular quantum cosmological setting, extending the results reported in \cite{10,11}. In more detail, our case study is constituted by a spatially closed Friedmann-Lema\^{\i}tre-Robertson-Walker universe, in the presence of a conformally coupled scalar fi...
1709.03027
Jose Ademir Sales Lima
A. P. Santos, R. Silva, J. S. Alcaniz, J. A. S. Lima
Nonextensive Kinetic Theory and H-Theorem in General Relativity
12 pages, no figures. Accepted for publication in Annals of Physics
null
10.1016/j.aop.2017.08.027
null
gr-qc cond-mat.quant-gas
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The nonextensive kinetic theory for degenerate quantum gases is discussed in the general relativistic framework. By incorporating nonadditive modifications in the collisional term of the relativistic Boltzmann equation and entropy current, it is shown that Tsallis entropic framework satisfies a H-theorem in the prese...
[ { "created": "Sun, 10 Sep 2017 02:27:47 GMT", "version": "v1" } ]
2017-10-25
[ [ "Santos", "A. P.", "" ], [ "Silva", "R.", "" ], [ "Alcaniz", "J. S.", "" ], [ "Lima", "J. A. S.", "" ] ]
The nonextensive kinetic theory for degenerate quantum gases is discussed in the general relativistic framework. By incorporating nonadditive modifications in the collisional term of the relativistic Boltzmann equation and entropy current, it is shown that Tsallis entropic framework satisfies a H-theorem in the presenc...
1302.4300
Mehmet Kavuk Mr.
N. Katirci, Mehmet Kavuk
$f(R,{T_{\mu\nu} T^{\mu\nu}})$ gravity and Cardassian-like expansion as one of its consequences
13 pages, 1 figure, matches published version
Eur. Phys. J. Plus (2014) 129: 163
10.1140/epjp/i2014-14163-6
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a new model of gravity where the Ricci scalar (R) in Einstein-Hilbert action is replaced by an arbitrary function of R and of the norm of energy-momentum tensor i.e., $f(R,T_{\mu\nu}T^{\mu\nu})$. Field equations are derived in the metric formalism. We find that the equation of motion of massive test partic...
[ { "created": "Mon, 18 Feb 2013 15:03:26 GMT", "version": "v1" }, { "created": "Mon, 10 Feb 2014 17:03:27 GMT", "version": "v2" }, { "created": "Fri, 1 Aug 2014 04:16:23 GMT", "version": "v3" } ]
2014-08-04
[ [ "Katirci", "N.", "" ], [ "Kavuk", "Mehmet", "" ] ]
We propose a new model of gravity where the Ricci scalar (R) in Einstein-Hilbert action is replaced by an arbitrary function of R and of the norm of energy-momentum tensor i.e., $f(R,T_{\mu\nu}T^{\mu\nu})$. Field equations are derived in the metric formalism. We find that the equation of motion of massive test particle...
1112.2714
Delsate T\'erence
T\'erence Delsate and Nobuyuki Sawado
Localizing modes of massive fermions and a U(1) gauge field in the inflating baby-skyrmion branes
20 pages, 13 figures, to appear in PRD. Typo corrected, matches published version
null
10.1103/PhysRevD.85.065025
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider the six dimensional brane world model, where the brane is described by a localized solution to the baby-Skyrme model extending in the extradimensions. The branes have a cosmological constant modeled by inflating four dimensional slices and we further consider a bulk cosmological constant. We focus on the ...
[ { "created": "Mon, 12 Dec 2011 21:01:42 GMT", "version": "v1" }, { "created": "Fri, 24 Feb 2012 17:16:19 GMT", "version": "v2" }, { "created": "Thu, 12 Apr 2012 09:05:44 GMT", "version": "v3" } ]
2015-06-03
[ [ "Delsate", "Térence", "" ], [ "Sawado", "Nobuyuki", "" ] ]
We consider the six dimensional brane world model, where the brane is described by a localized solution to the baby-Skyrme model extending in the extradimensions. The branes have a cosmological constant modeled by inflating four dimensional slices and we further consider a bulk cosmological constant. We focus on the to...
gr-qc/0307022
Benjamin C. Harms
Roberto Casadio, Sergio Fabi, Benjamin Harms
Electromagnetic waves around dilatonic stars and naked singularities
9 pages, 1 figure
Phys.Rev. D70 (2004) 044026
10.1103/PhysRevD.70.044026
null
gr-qc astro-ph hep-th
null
We study the propagation of classical electromagnetic waves on the simplest four-dimensional spherically symmetric metric with a dilaton background field. Solutions to the relevant equations are obtained perturbatively in a parameter which measures the strength of the dilaton field (hence parameterizes the departure ...
[ { "created": "Mon, 7 Jul 2003 19:02:13 GMT", "version": "v1" } ]
2009-11-10
[ [ "Casadio", "Roberto", "" ], [ "Fabi", "Sergio", "" ], [ "Harms", "Benjamin", "" ] ]
We study the propagation of classical electromagnetic waves on the simplest four-dimensional spherically symmetric metric with a dilaton background field. Solutions to the relevant equations are obtained perturbatively in a parameter which measures the strength of the dilaton field (hence parameterizes the departure fr...
2210.00287
Laszlo Arpad Gergely
Cec\'ilia Nagy, Zolt\'an Keresztes, L\'aszl\'o \'A. Gergely
Spherically symmetric, static black holes with scalar hair, and naked singularities in nonminimally coupled k-essence
20 pages, 4 figures
Phys. Rev. D 103, 124056 (2021)
10.1103/PhysRevD.103.124056
null
gr-qc hep-th
http://creativecommons.org/licenses/by/4.0/
We apply a recently developed 2+1+1 decomposition of spacetime, based on a nonorthogonal double foliation for the study of spherically symmetric, static black hole solutions of Horndeski scalar-tensor theory. Our discussion proceeds in an effective field theory (EFT) of modified gravity approach, with the action depe...
[ { "created": "Sat, 1 Oct 2022 14:22:39 GMT", "version": "v1" } ]
2022-10-04
[ [ "Nagy", "Cecília", "" ], [ "Keresztes", "Zoltán", "" ], [ "Gergely", "László Á.", "" ] ]
We apply a recently developed 2+1+1 decomposition of spacetime, based on a nonorthogonal double foliation for the study of spherically symmetric, static black hole solutions of Horndeski scalar-tensor theory. Our discussion proceeds in an effective field theory (EFT) of modified gravity approach, with the action depend...
gr-qc/0101119
Brien C. Nolan
Brien C. Nolan
A note on behaviour at an isotropic singularity
13 pp. plain latex. To appear in Classical and Quantum Gravity
Class.Quant.Grav. 18 (2001) 1127-1136
10.1088/0264-9381/18/6/311
null
gr-qc
null
The behaviour of Jacobi fields along a time-like geodesic running into an isotropic singularity is studied. It is shown that the Jacobi fields are crushed to zero length at a rate which is the same in every direction orthogonal to the geodesic. We show by means of a counter-example that this crushing effect depends c...
[ { "created": "Tue, 30 Jan 2001 15:47:54 GMT", "version": "v1" } ]
2009-11-07
[ [ "Nolan", "Brien C.", "" ] ]
The behaviour of Jacobi fields along a time-like geodesic running into an isotropic singularity is studied. It is shown that the Jacobi fields are crushed to zero length at a rate which is the same in every direction orthogonal to the geodesic. We show by means of a counter-example that this crushing effect depends cru...
gr-qc/9411055
Karen Brewster
Abhay Ashtekar
Recent Mathematical Developments in Quantum General Relativity
14 pages, TEX, no figures, Preprint CGPG-94/9-4
null
null
null
gr-qc hep-th
null
After a brief chronological sketch of developments in non-perturbative canonical quantum gravity, some of the recent mathematical results are reviewed. These include: i) an explicit construction of the quantum counterpart of Wheeler's superspace; ii) a rigorous procedure leading to the general solution of the diffeom...
[ { "created": "Mon, 21 Nov 1994 21:47:42 GMT", "version": "v1" }, { "created": "Wed, 23 Nov 1994 19:14:27 GMT", "version": "v2" } ]
2008-02-03
[ [ "Ashtekar", "Abhay", "" ] ]
After a brief chronological sketch of developments in non-perturbative canonical quantum gravity, some of the recent mathematical results are reviewed. These include: i) an explicit construction of the quantum counterpart of Wheeler's superspace; ii) a rigorous procedure leading to the general solution of the diffeomor...
2102.07578
Vasilios Zarikas
Fotios K. Anagnostopoulos, Georgios Kofinas, Vasilios Zarikas
IR quantum gravity solves naturally cosmic acceleration and its coincidence problem
7 pages
Int.J.Mod.Phys.D 28 (2019) 14, 1944013
10.1142/S0218271819440139
null
gr-qc hep-ph hep-th
http://creativecommons.org/licenses/by/4.0/
The novel idea is that the undergoing accelerated expansion of the universe happens due to infrared quantum gravity modifications at intermediate astrophysical scales of galaxies or galaxy clusters, within the framework of Asymptotically Safe gravity. The reason is that structures of matter are associated with a scal...
[ { "created": "Mon, 15 Feb 2021 14:37:19 GMT", "version": "v1" } ]
2021-02-16
[ [ "Anagnostopoulos", "Fotios K.", "" ], [ "Kofinas", "Georgios", "" ], [ "Zarikas", "Vasilios", "" ] ]
The novel idea is that the undergoing accelerated expansion of the universe happens due to infrared quantum gravity modifications at intermediate astrophysical scales of galaxies or galaxy clusters, within the framework of Asymptotically Safe gravity. The reason is that structures of matter are associated with a scale-...
1711.07486
Christian Friedrich Steinwachs
Michael S. Ruf and Christian F. Steinwachs
Quantum equivalence of $f(R)$ gravity and scalar-tensor theories
7 pages, 1 figure; references added, accepted for publication in Phys. Rev. D
Phys. Rev. D 97, 044050 (2018)
10.1103/PhysRevD.97.044050
FR-PHENO-2017-021
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate whether the classical equivalence of $f(R)$ gravity and its formulation as scalar-tensor theory still holds at the quantum level. We explicitly compare the corresponding one-loop divergences and find that the equivalence is broken by off-shell quantum corrections, but recovered on-shell.
[ { "created": "Mon, 20 Nov 2017 19:00:01 GMT", "version": "v1" }, { "created": "Wed, 31 Jan 2018 16:58:57 GMT", "version": "v2" } ]
2018-03-07
[ [ "Ruf", "Michael S.", "" ], [ "Steinwachs", "Christian F.", "" ] ]
We investigate whether the classical equivalence of $f(R)$ gravity and its formulation as scalar-tensor theory still holds at the quantum level. We explicitly compare the corresponding one-loop divergences and find that the equivalence is broken by off-shell quantum corrections, but recovered on-shell.
gr-qc/0306052
Eric Poisson
Eric Poisson
The motion of point particles in curved spacetime
LaTeX2e, 116 pages, 10 figures. This is the final version, as it will appear in Living Reviews in Relativity
LivingRev.Rel.7:6,2004
10.12942/lrr-2004-6
null
gr-qc
null
This review is concerned with the motion of a point scalar charge, a point electric charge, and a point mass in a specified background spacetime. In each of the three cases the particle produces a field that behaves as outgoing radiation in the wave zone, and therefore removes energy from the particle. In the near zo...
[ { "created": "Thu, 12 Jun 2003 15:51:54 GMT", "version": "v1" }, { "created": "Tue, 15 Jul 2003 22:11:42 GMT", "version": "v2" }, { "created": "Thu, 1 Apr 2004 17:13:12 GMT", "version": "v3" } ]
2016-10-19
[ [ "Poisson", "Eric", "" ] ]
This review is concerned with the motion of a point scalar charge, a point electric charge, and a point mass in a specified background spacetime. In each of the three cases the particle produces a field that behaves as outgoing radiation in the wave zone, and therefore removes energy from the particle. In the near zone...
0710.0628
Woei Chet Lim
Woei Chet Lim
New explicit spike solution -- non-local component of the generalized Mixmaster attractor
Significantly revised. Colour figures simplified to accommodate non-colour printing
Class.Quant.Grav.25:045014,2008
10.1088/0264-9381/25/4/045014
null
gr-qc
null
By applying a standard solution-generating transformation to an arbitrary vacuum Bianchi type II solution, one generates a new solution with spikes commonly observed in numerical simulations. It is conjectured that the spike solution is part of the generalized Mixmaster attractor.
[ { "created": "Tue, 2 Oct 2007 20:06:49 GMT", "version": "v1" }, { "created": "Wed, 6 Feb 2008 01:22:37 GMT", "version": "v2" } ]
2008-11-26
[ [ "Lim", "Woei Chet", "" ] ]
By applying a standard solution-generating transformation to an arbitrary vacuum Bianchi type II solution, one generates a new solution with spikes commonly observed in numerical simulations. It is conjectured that the spike solution is part of the generalized Mixmaster attractor.
gr-qc/9904068
null
John Ellis, N.E. Mavromatos and D.V. Nanopoulos
Quantum-Gravitational Diffusion and Stochastic Fluctuations in the Velocity of Light
17 pages LATEX, uses axodraw style file
Gen.Rel.Grav.32:127-144,2000
10.1023/A:1001852601248
ACT-3/99, CTP-TAMU-18/99 and OUTP--99--05P
gr-qc astro-ph hep-ph hep-th
null
We argue that quantum-gravitational fluctuations in the space-time background give the vacuum non-trivial optical properties that include diffusion and consequent uncertainties in the arrival times of photons, causing stochastic fluctuations in the velocity of light ``in vacuo''. Our proposal is motivated within a Li...
[ { "created": "Mon, 26 Apr 1999 22:17:02 GMT", "version": "v1" } ]
2009-09-11
[ [ "Ellis", "John", "" ], [ "Mavromatos", "N. E.", "" ], [ "Nanopoulos", "D. V.", "" ] ]
We argue that quantum-gravitational fluctuations in the space-time background give the vacuum non-trivial optical properties that include diffusion and consequent uncertainties in the arrival times of photons, causing stochastic fluctuations in the velocity of light ``in vacuo''. Our proposal is motivated within a Liou...
2401.03669
Weilong Luo
Weilong Luo, Chang Liu, Zong-Kuan Guo
Constraints on Einstein-dilaton Gauss-Bonnet gravity with Taiji
14 pages, 2 figures. version accepted by EPJC
Eur. Phys. J. C 84, 394 (2024)
10.1140/epjc/s10052-024-12735-4
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In the 2030s, space-based gravitational-wave (GW) detectors will exhibit unprecedented sensitivity in the millihertz frequency band, greatly expanding the potential for testing theories of gravity compared to ground-based GW detectors. Inspired by effective string theory, Einstein-dilaton Gauss-Bonnet (EdGB) gravity ...
[ { "created": "Mon, 8 Jan 2024 05:24:20 GMT", "version": "v1" }, { "created": "Mon, 15 Apr 2024 01:41:37 GMT", "version": "v2" } ]
2024-04-16
[ [ "Luo", "Weilong", "" ], [ "Liu", "Chang", "" ], [ "Guo", "Zong-Kuan", "" ] ]
In the 2030s, space-based gravitational-wave (GW) detectors will exhibit unprecedented sensitivity in the millihertz frequency band, greatly expanding the potential for testing theories of gravity compared to ground-based GW detectors. Inspired by effective string theory, Einstein-dilaton Gauss-Bonnet (EdGB) gravity in...
2101.05745
Tapobrata Sarkar
Sandip Chowdhury, Kunal Pal, Kuntal Pal, Tapobrata Sarkar
Disformal transformations and the motion of a particle in semi-classical gravity
18 Pages, LaTeX
null
10.1140/epjc/s10052-021-09751-z
null
gr-qc hep-th quant-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The approach to incorporate quantum effects in gravity by replacing free particle geodesics with Bohmian non-geodesic trajectories has an equivalent description in terms of a conformally related geometry, where the motion is force free, with the quantum effects inside the conformal factor, i.e., in the geometry itsel...
[ { "created": "Thu, 14 Jan 2021 17:47:28 GMT", "version": "v1" } ]
2021-11-10
[ [ "Chowdhury", "Sandip", "" ], [ "Pal", "Kunal", "" ], [ "Pal", "Kuntal", "" ], [ "Sarkar", "Tapobrata", "" ] ]
The approach to incorporate quantum effects in gravity by replacing free particle geodesics with Bohmian non-geodesic trajectories has an equivalent description in terms of a conformally related geometry, where the motion is force free, with the quantum effects inside the conformal factor, i.e., in the geometry itself....
2310.03520
Yi-Ming Hu
Chang-Qing Ye, Hui-Min Fan, Alejandro Torres-Orjuela, Jian-dong Zhang, Yi-Ming Hu
Identification of Gravitational-waves from Extreme Mass Ratio Inspirals
15 pages, 6 figures, comments welcom
null
null
null
gr-qc astro-ph.GA astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Space-based gravitational wave detectors like TianQin or LISA could observe extreme-mass-ratio-inspirals (EMRIs) at millihertz frequencies. The accurate identification of these EMRI signals from the data plays a crucial role in enabling in-depth study of astronomy and physics. We aim at the identification stage of th...
[ { "created": "Thu, 5 Oct 2023 13:09:28 GMT", "version": "v1" } ]
2023-10-06
[ [ "Ye", "Chang-Qing", "" ], [ "Fan", "Hui-Min", "" ], [ "Torres-Orjuela", "Alejandro", "" ], [ "Zhang", "Jian-dong", "" ], [ "Hu", "Yi-Ming", "" ] ]
Space-based gravitational wave detectors like TianQin or LISA could observe extreme-mass-ratio-inspirals (EMRIs) at millihertz frequencies. The accurate identification of these EMRI signals from the data plays a crucial role in enabling in-depth study of astronomy and physics. We aim at the identification stage of the ...
2005.05573
Rajesh Kumar
Rajesh Kumar and S. K. Srivastava
Dynamical model of expansion free dissipative perfect fluids in general relativity
Require comments
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper deals with the spherically symmetric self-gravitating star which is considered to be expansion free dissipative perfect fluids distribution. Some recent research reveals that expansion free dynamical star must be accelerating and dissipating. We adopted some conjectures to obtain the analytical solution fo...
[ { "created": "Tue, 12 May 2020 06:49:38 GMT", "version": "v1" } ]
2020-05-13
[ [ "Kumar", "Rajesh", "" ], [ "Srivastava", "S. K.", "" ] ]
This paper deals with the spherically symmetric self-gravitating star which is considered to be expansion free dissipative perfect fluids distribution. Some recent research reveals that expansion free dynamical star must be accelerating and dissipating. We adopted some conjectures to obtain the analytical solution for ...
gr-qc/0310045
Luciano Rezzolla
Luciano Rezzolla, Olindo Zanotti, Jose A. Font
Dynamics of thick discs around Schwarzschild-de Sitter black holes
12 pages; A&A, in press
Astron.Astrophys. 412 (2003) 603
10.1051/0004-6361:20031457
null
gr-qc astro-ph
null
We consider the effects of a cosmological constant on the dynamics of constant angular momentum discs orbiting Schwarzschild-de Sitter black holes. The motivation behind this study is to investigate whether the presence of a radial force contrasting the black hole's gravitational attraction can influence the occurren...
[ { "created": "Tue, 7 Oct 2003 17:14:55 GMT", "version": "v1" } ]
2009-11-10
[ [ "Rezzolla", "Luciano", "" ], [ "Zanotti", "Olindo", "" ], [ "Font", "Jose A.", "" ] ]
We consider the effects of a cosmological constant on the dynamics of constant angular momentum discs orbiting Schwarzschild-de Sitter black holes. The motivation behind this study is to investigate whether the presence of a radial force contrasting the black hole's gravitational attraction can influence the occurrence...
gr-qc/0006005
Steven L. Liebling
Steven L. Liebling
Black Hole Critical Phenomena Without Black Holes
13 pages, 6 figures; Submission for the proceedings of ICGC 2000 in the journal Premana
Pramana 55:497-509,2000
10.1007/s12043-000-0162-6
null
gr-qc
null
Studying the threshold of black hole formation via numerical evolution has led to the discovery of fascinating nonlinear phenomena. Power-law mass scaling, aspects of universality, and self-similarity have now been found for a large variety of models. However, questions remain. Here I briefly review critical phenomen...
[ { "created": "Fri, 2 Jun 2000 17:44:44 GMT", "version": "v1" } ]
2009-10-31
[ [ "Liebling", "Steven L.", "" ] ]
Studying the threshold of black hole formation via numerical evolution has led to the discovery of fascinating nonlinear phenomena. Power-law mass scaling, aspects of universality, and self-similarity have now been found for a large variety of models. However, questions remain. Here I briefly review critical phenomena,...
1806.04766
Lei Feng
Lei Feng (Purple Mountain Observatory)
The Energy Dependence of Micro Black Hole Horizon in Quantum Gravity Theory
4 pages, 1 figure, published in Eur.Phys.J.Plus
Eur.Phys.J.Plus 134 (2019) no.8, 388
10.1140/epjp/i2019-12781-0
null
gr-qc astro-ph.HE hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The energy dependence of the deflection angle is a common prediction in some quantum gravity theories when the impact parameters are much larger than the photon wavelength. For low energy photons, the deflection angle recovers to the prediction of GR. But it reduces to zero for infinite energy photons. In this paper,...
[ { "created": "Sun, 10 Jun 2018 16:14:05 GMT", "version": "v1" }, { "created": "Fri, 14 Dec 2018 06:10:55 GMT", "version": "v2" }, { "created": "Thu, 10 Oct 2019 02:46:03 GMT", "version": "v3" } ]
2019-10-11
[ [ "Feng", "Lei", "", "Purple Mountain Observatory" ] ]
The energy dependence of the deflection angle is a common prediction in some quantum gravity theories when the impact parameters are much larger than the photon wavelength. For low energy photons, the deflection angle recovers to the prediction of GR. But it reduces to zero for infinite energy photons. In this paper, w...
gr-qc/9904060
S. K. Moayedi
M. A. Jafarizadeh, H. Fakhri, S. K. Moayedi
2+1-Gravity and The Embedding its Dynamiycal Symmetry and Para-Supersymmetry into SO(4,c) Group
16 page, Latex, no figures
null
null
null
gr-qc
null
Some special solutions of the Einstein-Maxwell action with a non-negative cosmological constant and a very heavy point mass particle have been obtained. The solutions correspond to static spacetime of locally constant curvature in its spatial part and a constant magnetic field of a magnetic monopole together with def...
[ { "created": "Sat, 24 Apr 1999 18:34:41 GMT", "version": "v1" } ]
2007-05-23
[ [ "Jafarizadeh", "M. A.", "" ], [ "Fakhri", "H.", "" ], [ "Moayedi", "S. K.", "" ] ]
Some special solutions of the Einstein-Maxwell action with a non-negative cosmological constant and a very heavy point mass particle have been obtained. The solutions correspond to static spacetime of locally constant curvature in its spatial part and a constant magnetic field of a magnetic monopole together with defic...
gr-qc/0310109
Bryan Kelleher
Bryan Kelleher
Scale-invariance in gravity and implications for the cosmological constant
Replaced with final version: minor changes to text; references added
Class. Quantum Grav. 21 (2004) 2623-39
10.1088/0264-9381/21/11/008
null
gr-qc
null
Recently a scale invariant theory of gravity was constructed by imposing a conformal symmetry on general relativity. The imposition of this symmetry changed the configuration space from superspace - the space of all Riemannian 3-metrics modulo diffeomorphisms - to conformal superspace - the space of all Riemannian 3-...
[ { "created": "Fri, 24 Oct 2003 21:23:15 GMT", "version": "v1" }, { "created": "Sat, 25 Oct 2003 13:38:52 GMT", "version": "v2" }, { "created": "Mon, 26 Apr 2004 23:40:54 GMT", "version": "v3" } ]
2009-11-10
[ [ "Kelleher", "Bryan", "" ] ]
Recently a scale invariant theory of gravity was constructed by imposing a conformal symmetry on general relativity. The imposition of this symmetry changed the configuration space from superspace - the space of all Riemannian 3-metrics modulo diffeomorphisms - to conformal superspace - the space of all Riemannian 3-me...
2011.03547
William East
William E. East and Justin L. Ripley
Evolution of Einstein-scalar-Gauss-Bonnet gravity using a modified harmonic formulation
23 pages, 13 figures; revised to match PRD version
Phys. Rev. D 103, 044040 (2021)
10.1103/PhysRevD.103.044040
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present numerical solutions of several spacetimes of physical interest, including binary black hole mergers, in shift-symmetric Einstein-scalar-Gauss-Bonnet (ESGB) gravity, and describe our methods for solving the full equations of motion, without approximation, for general spacetimes. While we concentrate on the ...
[ { "created": "Fri, 6 Nov 2020 19:00:00 GMT", "version": "v1" }, { "created": "Sat, 20 Feb 2021 20:52:47 GMT", "version": "v2" } ]
2021-02-25
[ [ "East", "William E.", "" ], [ "Ripley", "Justin L.", "" ] ]
We present numerical solutions of several spacetimes of physical interest, including binary black hole mergers, in shift-symmetric Einstein-scalar-Gauss-Bonnet (ESGB) gravity, and describe our methods for solving the full equations of motion, without approximation, for general spacetimes. While we concentrate on the sp...
1902.03621
Charles Schwartz
Charles Schwartz
An Approach for Modelling Tachyons with Gravitation
20 pages; major revision starting with Section 5
null
10.1142/S0217751X19501033
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This work expands previous efforts, within the classical theories of Special and General Relativity, to include tachyons (faster-than-light particles) along with ordinary (slower-than-light) particles at any energy. The objective here is to construct a Hamiltonian that includes both the particles and the gravitationa...
[ { "created": "Sun, 10 Feb 2019 15:25:29 GMT", "version": "v1" }, { "created": "Mon, 20 May 2019 22:39:59 GMT", "version": "v2" }, { "created": "Sat, 15 Jun 2019 13:24:14 GMT", "version": "v3" } ]
2019-07-24
[ [ "Schwartz", "Charles", "" ] ]
This work expands previous efforts, within the classical theories of Special and General Relativity, to include tachyons (faster-than-light particles) along with ordinary (slower-than-light) particles at any energy. The objective here is to construct a Hamiltonian that includes both the particles and the gravitational ...