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2312.07237
Inna Ivanova
Victor Berezin, Inna Ivanova
Conformal invariance, cosmological particle production and imitation of dark matter
Based on the talk presented at the ICAA-2023 Virtual Conference
null
null
null
gr-qc
http://creativecommons.org/licenses/by-sa/4.0/
Using a model for an ideal fluid with a variable number of particles, a phenomenological description of the processes of particle production in strong external fields is investigated. The conformal invariance of the creation law is shown, which imposes rather rigorous restrictions on the possible types of sources. It...
[ { "created": "Tue, 12 Dec 2023 13:06:43 GMT", "version": "v1" } ]
2023-12-13
[ [ "Berezin", "Victor", "" ], [ "Ivanova", "Inna", "" ] ]
Using a model for an ideal fluid with a variable number of particles, a phenomenological description of the processes of particle production in strong external fields is investigated. The conformal invariance of the creation law is shown, which imposes rather rigorous restrictions on the possible types of sources. It a...
1702.06855
Ahmadjon Abdujabbarov
Bobir Toshmatov, Cosimo Bambi, Bobomurat Ahmedov, Ahmadjon Abdujabbarov, Zden\v{e}k Stuchl\'ik
Energy conditions of non-singular black hole spacetimes in conformal gravity
10 pages, 9 figures
Eur. Phys. J. C (2017) 77:542
10.1140/epjc/s10052-017-5112-2
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Conformal gravity can elegantly solve the problem of spacetime singularities present in Einstein's gravity. For every physical spacetime, there is an infinite family of conformally-equivalent singularity-free metrics. In the unbroken phase, every non-singular metric is equivalent and can be used to infer the physical...
[ { "created": "Tue, 21 Feb 2017 13:24:49 GMT", "version": "v1" }, { "created": "Mon, 14 Aug 2017 10:50:55 GMT", "version": "v2" } ]
2017-08-15
[ [ "Toshmatov", "Bobir", "" ], [ "Bambi", "Cosimo", "" ], [ "Ahmedov", "Bobomurat", "" ], [ "Abdujabbarov", "Ahmadjon", "" ], [ "Stuchlík", "Zdeněk", "" ] ]
Conformal gravity can elegantly solve the problem of spacetime singularities present in Einstein's gravity. For every physical spacetime, there is an infinite family of conformally-equivalent singularity-free metrics. In the unbroken phase, every non-singular metric is equivalent and can be used to infer the physical p...
2407.09591
Yongqiang Wang
Xin Su, Chen-Hao Hao, Yong-Qiang Wang
Ellis wormhole with nonlinear electromagnetic field
21 pages, 8 figures. arXiv admin note: text overlap with arXiv:2311.17557
null
null
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we present the spherically symmetric wormhole in Einstein's gravity coupling phantom field and nonlinear electromagnetic field. Numerical results show that this solution violates the Null Energy Condition (NEC), and as the parameters change, the ADM mass of the entire spacetime changes from positive to...
[ { "created": "Fri, 12 Jul 2024 17:31:52 GMT", "version": "v1" } ]
2024-07-16
[ [ "Su", "Xin", "" ], [ "Hao", "Chen-Hao", "" ], [ "Wang", "Yong-Qiang", "" ] ]
In this paper, we present the spherically symmetric wormhole in Einstein's gravity coupling phantom field and nonlinear electromagnetic field. Numerical results show that this solution violates the Null Energy Condition (NEC), and as the parameters change, the ADM mass of the entire spacetime changes from positive to n...
1011.5848
Amitai Bin-Nun
Amitai Y. Bin-Nun
Strong Gravitational Lensing by Sgr A*
13 pages, 9 figures. Submitted as invited review article for the GR19 issue of CQG
Class.Quant.Grav.28:114003,2011
10.1088/0264-9381/28/11/114003
null
gr-qc astro-ph.HE hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In recent years, there has been increasing recognition of the potential of the galactic center as a probe of general relativity in the strong field. There is almost certainly a black hole at Sgr A* in the galactic center, and this would allow us the opportunity to probe dynamics near the exterior of the black hole. I...
[ { "created": "Fri, 26 Nov 2010 17:54:43 GMT", "version": "v1" } ]
2011-05-24
[ [ "Bin-Nun", "Amitai Y.", "" ] ]
In recent years, there has been increasing recognition of the potential of the galactic center as a probe of general relativity in the strong field. There is almost certainly a black hole at Sgr A* in the galactic center, and this would allow us the opportunity to probe dynamics near the exterior of the black hole. In ...
gr-qc/9512046
Nobuyuki Sakai
Nobuyuki Sakai
Dynamic Monopoles and Spacetime Structure
2 pages, latex, uuencoded postscript figures; based on gr-qc/9512045, and presented at 1st RESCUE International Symposium THE COSMOLOGICAL CONSTANT AND THE EVOLUTION OF THE UNIVERSE, The University of Tokyo, November 7-10, 1995
null
null
WU-AP/56/95
gr-qc astro-ph hep-th
null
According to previous work on magnetic monopoles, static regular solutions are nonexistent if the vacuum expectation value of the Higgs field $\eta$ is larger than a critical value $\eta_{{\rm cr}}$, which is of the order of the Planck mass. In order to understand the properties of monopoles for $\eta>\eta_{{\rm cr}}...
[ { "created": "Thu, 28 Dec 1995 22:04:01 GMT", "version": "v1" }, { "created": "Mon, 8 Jan 1996 07:52:42 GMT", "version": "v2" } ]
2008-02-03
[ [ "Sakai", "Nobuyuki", "" ] ]
According to previous work on magnetic monopoles, static regular solutions are nonexistent if the vacuum expectation value of the Higgs field $\eta$ is larger than a critical value $\eta_{{\rm cr}}$, which is of the order of the Planck mass. In order to understand the properties of monopoles for $\eta>\eta_{{\rm cr}}$,...
2010.06461
Marios Bounakis
Marios Bounakis, Ian G. Moss, Gerasimos Rigopoulos
Observational constraints on Hyperinflation
16 pages, 12 figures
null
10.1088/1475-7516/2021/02/006
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study a Hyperinflation model involving a field doublet on a hyperbolic field-space manifold and an exponential potential, providing a concise treatment of the evolution of the entropic and adiabatic perturbations around the homogeneous hyperbolic attractor solution. We find that the adiabatic spectral index narrow...
[ { "created": "Tue, 13 Oct 2020 15:14:05 GMT", "version": "v1" }, { "created": "Fri, 5 Feb 2021 16:49:01 GMT", "version": "v2" } ]
2021-02-08
[ [ "Bounakis", "Marios", "" ], [ "Moss", "Ian G.", "" ], [ "Rigopoulos", "Gerasimos", "" ] ]
We study a Hyperinflation model involving a field doublet on a hyperbolic field-space manifold and an exponential potential, providing a concise treatment of the evolution of the entropic and adiabatic perturbations around the homogeneous hyperbolic attractor solution. We find that the adiabatic spectral index narrows ...
gr-qc/9209015
Juan Garcia-Bellido
Luis J. Garay and Juan Garcia-Bellido
Jordan-Brans-Dicke Quantum Wormholes and Coleman's Mechanism
22 pp, 1 figure available upon request, LaTeX. Conclusions have been changed
Nucl.Phys. B400 (1993) 416-434
10.1016/0550-3213(93)90411-H
IEM-FT-59/92
gr-qc hep-th
null
We consider the quantum gravity and cosmology of a Jordan-Brans-Dicke theory, predicted by string effective actions. We study its canonical formalism and find that the constraint algebra is that of general relativity, as a consequence of the general covariance of scalar-tensor theories. We also analyze the problem of...
[ { "created": "Wed, 30 Sep 1992 16:58:14 GMT", "version": "v1" }, { "created": "Mon, 5 Oct 1992 18:58:22 GMT", "version": "v2" } ]
2009-10-22
[ [ "Garay", "Luis J.", "" ], [ "Garcia-Bellido", "Juan", "" ] ]
We consider the quantum gravity and cosmology of a Jordan-Brans-Dicke theory, predicted by string effective actions. We study its canonical formalism and find that the constraint algebra is that of general relativity, as a consequence of the general covariance of scalar-tensor theories. We also analyze the problem of b...
1412.8195
Vasilis Oikonomou
V.K. Oikonomou
Loop Quantum Cosmology Matter Bounce Reconstruction from $F(R)$ Gravity Using an Auxiliary Field
Revised version to appear in GERG
null
10.1007/s10714-015-1970-9
null
gr-qc astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Using the reconstruction technique with an auxiliary field, we investigate which $F(R)$ gravities can produce the matter bounce cosmological solutions. Owing to the specific functional form of the matter bounce Hubble parameter, the reconstruction technique leads, after some simplifications, to the same Hubble parame...
[ { "created": "Sun, 28 Dec 2014 18:35:34 GMT", "version": "v1" }, { "created": "Thu, 8 Oct 2015 13:32:27 GMT", "version": "v2" } ]
2015-11-04
[ [ "Oikonomou", "V. K.", "" ] ]
Using the reconstruction technique with an auxiliary field, we investigate which $F(R)$ gravities can produce the matter bounce cosmological solutions. Owing to the specific functional form of the matter bounce Hubble parameter, the reconstruction technique leads, after some simplifications, to the same Hubble paramete...
1411.0242
Plamen Fiziev
Plamen Fiziev
Dark Energy and Dark Matter in Stars Physic
Latex file, 7 pages, 11 figures. Symposium "Frontiers of Fundamental Physics 14", Marseille, France. arXiv admin note: substantial text overlap with arXiv:1402.2813
Symposium "Frontiers of Fundamental Physics 14", Marseille, France, July, 15-18, 2014, PoS(FFP14)080
null
null
gr-qc astro-ph.CO hep-th math-ph math.MP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present the basic equations and relations for the relativistic static spherically symmetric stars (SSSS) in the model of minimal dilatonic gravity (MDG) which is {\em locally} equivalent to the f(R) theories of gravity and gives an alternative description of the effects of dark matter and dark energy. The results ...
[ { "created": "Sun, 2 Nov 2014 11:25:19 GMT", "version": "v1" } ]
2014-11-05
[ [ "Fiziev", "Plamen", "" ] ]
We present the basic equations and relations for the relativistic static spherically symmetric stars (SSSS) in the model of minimal dilatonic gravity (MDG) which is {\em locally} equivalent to the f(R) theories of gravity and gives an alternative description of the effects of dark matter and dark energy. The results fo...
2110.15541
Theo Verwimp
Theo Verwimp
Unified prescription for the generation of electroweak and gravitational gauge field Lagrangian on a principal fiber bundle
12 pages, adapted version of the original publication: references changed, conclusions unchanged
J.Math.Phys.31(12),December 1990,pages 3047-3052
10.1063/1.528957
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Glashow-Weinberg-Salam gauge field Lagrangian for electroweak theory and the Townsend-Zardecki action for gravitation are obtained from the same type of Yang-Mills Weil form on a principal fiber bundle over space-time, with symmetry group U(2) and SO(2,3), respectively. The unified geometrical approach given here...
[ { "created": "Fri, 29 Oct 2021 05:12:14 GMT", "version": "v1" } ]
2021-11-03
[ [ "Verwimp", "Theo", "" ] ]
The Glashow-Weinberg-Salam gauge field Lagrangian for electroweak theory and the Townsend-Zardecki action for gravitation are obtained from the same type of Yang-Mills Weil form on a principal fiber bundle over space-time, with symmetry group U(2) and SO(2,3), respectively. The unified geometrical approach given here s...
gr-qc/9608051
Jose Wadih Maluf
J. W. Maluf (Universidade de Brasilia)
On the distribution of gravitational energy in the de Sitter space
18 pages, LaTex file, no figures, to appear in the J. Math. Phys
J.Math.Phys. 37 (1996) 6293-6301
10.1063/1.531777
null
gr-qc
null
We calculate the total gravitational energy and the gravitational energy density of the de Sitter space using the definition of localized energy that arises in the framework of the teleparallel equivalent of general relativity. We find that the gravitational energy can only be defined within the cosmological horizon ...
[ { "created": "Wed, 21 Aug 1996 16:26:18 GMT", "version": "v1" } ]
2009-10-28
[ [ "Maluf", "J. W.", "", "Universidade de Brasilia" ] ]
We calculate the total gravitational energy and the gravitational energy density of the de Sitter space using the definition of localized energy that arises in the framework of the teleparallel equivalent of general relativity. We find that the gravitational energy can only be defined within the cosmological horizon an...
0712.0539
Bernard Linet
Bernard Linet
Electrostatics in a wormhole geometry
latex, 5 pages, a slight correction
null
null
null
gr-qc
null
We determine in closed form the electrostatic potential generated by a point charge at rest in a simple model of static spherically symmetric wormhole. From this, we deduce the electrostatic self-energy of this point charge.
[ { "created": "Tue, 4 Dec 2007 14:59:24 GMT", "version": "v1" }, { "created": "Mon, 14 Jan 2008 11:50:08 GMT", "version": "v2" } ]
2008-01-14
[ [ "Linet", "Bernard", "" ] ]
We determine in closed form the electrostatic potential generated by a point charge at rest in a simple model of static spherically symmetric wormhole. From this, we deduce the electrostatic self-energy of this point charge.
gr-qc/9608049
Jose Wadih Maluf
J. W. Maluf, E. F. Martins and A. Kneip (Universidade de Brasilia)
Gravitational energy of rotating black holes
18 pages, LaTex file, one figure
J.Math.Phys. 37 (1996) 6302-6310
10.1063/1.531778
null
gr-qc
null
In the teleparallel equivalent of general relativity the energy density of asymptotically flat gravitational fields can be naturaly defined as a scalar density restricted to a three-dimensional spacelike hypersurface $\Sigma$. Integration over the whole $\Sigma$ yields the standard ADM energy. After establishing the ...
[ { "created": "Wed, 21 Aug 1996 16:37:13 GMT", "version": "v1" } ]
2009-10-28
[ [ "Maluf", "J. W.", "", "Universidade de Brasilia" ], [ "Martins", "E. F.", "", "Universidade de Brasilia" ], [ "Kneip", "A.", "", "Universidade de Brasilia" ] ]
In the teleparallel equivalent of general relativity the energy density of asymptotically flat gravitational fields can be naturaly defined as a scalar density restricted to a three-dimensional spacelike hypersurface $\Sigma$. Integration over the whole $\Sigma$ yields the standard ADM energy. After establishing the re...
1904.04101
Peter K.F. Kuhfittig
Peter K.F. Kuhfittig
Thin-shell wormholes from Kiselev black holes
9 pages, 3 figures
Turk. J. Phys., vol. 43, 213-220 (2019)
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper discusses the theoretical construction of thin-shell wormholes from Kiselev black holes. We assume a barotropic equation of state for the exotic matter on the shell. While most of these wormholes are unstable to linearized radial perturbations, a limit argument is used to show that under certain conditions...
[ { "created": "Mon, 8 Apr 2019 14:48:06 GMT", "version": "v1" }, { "created": "Wed, 5 Jun 2019 14:58:57 GMT", "version": "v2" } ]
2019-06-06
[ [ "Kuhfittig", "Peter K. F.", "" ] ]
This paper discusses the theoretical construction of thin-shell wormholes from Kiselev black holes. We assume a barotropic equation of state for the exotic matter on the shell. While most of these wormholes are unstable to linearized radial perturbations, a limit argument is used to show that under certain conditions, ...
2209.15225
Hocheol Lee
Bum-Hoon Lee, Hochoel Lee, Wonwoo Lee, Nils A. Nilsson, and Somyadip Thakur
Induced cosmological anisotropy by a gauge-gravity interaction
46 pages, 15 figures; title of paper has been changed, added and clarified discussion of results, added figure, updated references. Accepted for publication in Physics of the Dark Universe
null
null
CQUeST-2022-0698
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a simple model which generates cosmological anisotropies on top of standard FLRW geometry. This is in some sense reminiscent of the mean field approximation, where the mean field cosmological model under consideration would be the standard FLRW, and the anisotropy is a small perturbative correction on top ...
[ { "created": "Fri, 30 Sep 2022 04:42:47 GMT", "version": "v1" }, { "created": "Wed, 21 Jun 2023 12:07:51 GMT", "version": "v2" }, { "created": "Thu, 21 Mar 2024 12:48:02 GMT", "version": "v3" } ]
2024-03-22
[ [ "Lee", "Bum-Hoon", "" ], [ "Lee", "Hochoel", "" ], [ "Lee", "Wonwoo", "" ], [ "Nilsson", "Nils A.", "" ], [ "Thakur", "Somyadip", "" ] ]
We present a simple model which generates cosmological anisotropies on top of standard FLRW geometry. This is in some sense reminiscent of the mean field approximation, where the mean field cosmological model under consideration would be the standard FLRW, and the anisotropy is a small perturbative correction on top of...
gr-qc/0601075
Anna M. Nobili
G. L. Comandi, M. L. Chiofalo, R. Toncelli, D. Bramanti, E. Polacco, and A. M. Nobili
Dynamical response of the "GGG" rotor to test the Equivalence Principle: theory, simulation and experiment. Part I: the normal modes
Accepted for publication by "Review of Scientific Instruments" on Jan 16, 2006. 16 2-column pages, 9 figures
Rev.Sci.Instrum. 77 (2006) 034501
10.1063/1.2173075
null
gr-qc
null
Recent theoretical work suggests that violation of the Equivalence Principle might be revealed in a measurement of the fractional differential acceleration $\eta$ between two test bodies -of different composition, falling in the gravitational field of a source mass- if the measurement is made to the level of $\eta\si...
[ { "created": "Wed, 18 Jan 2006 16:07:06 GMT", "version": "v1" } ]
2009-11-11
[ [ "Comandi", "G. L.", "" ], [ "Chiofalo", "M. L.", "" ], [ "Toncelli", "R.", "" ], [ "Bramanti", "D.", "" ], [ "Polacco", "E.", "" ], [ "Nobili", "A. M.", "" ] ]
Recent theoretical work suggests that violation of the Equivalence Principle might be revealed in a measurement of the fractional differential acceleration $\eta$ between two test bodies -of different composition, falling in the gravitational field of a source mass- if the measurement is made to the level of $\eta\sime...
gr-qc/9911086
Yungui Gong
Yungui Gong
On Holography in Brans-Dicke Cosmology
talk given at the 9th Midwest Relativity Conference held in University of Illinois at Urbana-Champaign, November 12-13, 1999. 8 figures
null
null
utexas-hep-20
gr-qc
null
The holographic bound in Brans-Dicke $k=1$ matter dominated Cosmology is discussed. In this talk, both the apparent horizon and the particle horizon are taken for the holographic bound. The covariant entropy conjecture proposed by Bousso is also discussed.
[ { "created": "Mon, 22 Nov 1999 20:25:14 GMT", "version": "v1" } ]
2007-05-23
[ [ "Gong", "Yungui", "" ] ]
The holographic bound in Brans-Dicke $k=1$ matter dominated Cosmology is discussed. In this talk, both the apparent horizon and the particle horizon are taken for the holographic bound. The covariant entropy conjecture proposed by Bousso is also discussed.
gr-qc/0702085
Andre Fuzfa
A. Fuzfa, J.-M. Alimi
An Awesome Hypothesis for Dark Energy : The Abnormally Weighting Energy
3 pages, 1 figure, prepared for the Proceedings of the 11th Marcel Grossmann Conference, held in Berlin, Germany, July 2006
null
10.1142/9789812834300_0256
null
gr-qc astro-ph
null
We introduce the Abnormally Weighting Energy (AWE) hypothesis in which dark energy (DE) is presented as a consequence of the violation of the weak equivalence principle (WEP) at cosmological scales by some dark sector. Indeed, this implies a violation of the strong equivalence principle (SEP) for ordinary matter and ...
[ { "created": "Thu, 15 Feb 2007 09:49:05 GMT", "version": "v1" } ]
2016-11-15
[ [ "Fuzfa", "A.", "" ], [ "Alimi", "J. -M.", "" ] ]
We introduce the Abnormally Weighting Energy (AWE) hypothesis in which dark energy (DE) is presented as a consequence of the violation of the weak equivalence principle (WEP) at cosmological scales by some dark sector. Indeed, this implies a violation of the strong equivalence principle (SEP) for ordinary matter and co...
1902.05129
Kayll Lake
Sheref Nasereldin and Kayll Lake
Boundary Orbits: 1 Static Spacetimes
4 pages revtex 4.1 Updated and expanded
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The study of circular orbits in spacetime is of astrophysical importance. The identification and classification of circular orbits in both static and stationary spacetimes remains an active area of interest. Even in the simplest static spherically symmetric case, it is well known that the introduction of a cosmologic...
[ { "created": "Wed, 13 Feb 2019 21:02:42 GMT", "version": "v1" }, { "created": "Wed, 5 Jun 2019 19:40:17 GMT", "version": "v2" } ]
2019-06-07
[ [ "Nasereldin", "Sheref", "" ], [ "Lake", "Kayll", "" ] ]
The study of circular orbits in spacetime is of astrophysical importance. The identification and classification of circular orbits in both static and stationary spacetimes remains an active area of interest. Even in the simplest static spherically symmetric case, it is well known that the introduction of a cosmological...
1312.1682
Muhammad Jamil Amir
M. Jamil Amir, Sadia Sattar
Locally Rotationally Symmetric Vacuum Solutions in f(R) Gravity
22 pages, Accepted for publication in Int. J. Theor. Phys
null
10.1007/s10773-013-1865-z
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper is devoted to find the Locally Rotationally Symmetric (LRS) vacuum solutions in the context of f(R) theory of gravity. Actually, we have considered the three metrics representing the whole family of LRS spacetimes and solved the field equations by using metric approach as well as the assumption of constant...
[ { "created": "Thu, 5 Dec 2013 07:12:51 GMT", "version": "v1" } ]
2015-06-18
[ [ "Amir", "M. Jamil", "" ], [ "Sattar", "Sadia", "" ] ]
This paper is devoted to find the Locally Rotationally Symmetric (LRS) vacuum solutions in the context of f(R) theory of gravity. Actually, we have considered the three metrics representing the whole family of LRS spacetimes and solved the field equations by using metric approach as well as the assumption of constant s...
gr-qc/0405136
B. S. Sathyaprakash
B.S. Sathyaprakash (Cardiff University)
Gravitational Radiation - Observing the Dark and Dense Universe
24 pages, invited review at ICRC2003, Tsukuba, Japan
null
null
null
gr-qc
null
Astronomical observations in the electromagnetic window - microwave, radio and optical - have revealed that most of the Universe is dark. The only reason we know that dark matter exists is because of its gravitational influence on luminous matter. It is plausible that a small fraction of that dark matter is clumped, ...
[ { "created": "Fri, 28 May 2004 00:05:07 GMT", "version": "v1" } ]
2007-05-23
[ [ "Sathyaprakash", "B. S.", "", "Cardiff University" ] ]
Astronomical observations in the electromagnetic window - microwave, radio and optical - have revealed that most of the Universe is dark. The only reason we know that dark matter exists is because of its gravitational influence on luminous matter. It is plausible that a small fraction of that dark matter is clumped, an...
2110.10667
Ilkka M\"akinen
Jerzy Lewandowski, Ilkka M\"akinen
Scalar curvature operator for models of loop quantum gravity on a cubical graph
v3: 43 pages, 5 figures. A few minor corrections. Expanded discussion in section 5.2. Version accepted for publication. v2: 41 pages, 5 figures. Major revision correcting an error in the previous version. v1: 30 pages, 3 figures
null
10.1103/PhysRevD.106.046013
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this article we introduce a new operator representing the three-dimensional scalar curvature in loop quantum gravity. Our construction does not apply to the entire kinematical Hilbert space of loop quantum gravity; instead, the operator is defined on the Hilbert space of a fixed cubical graph. The starting point o...
[ { "created": "Wed, 20 Oct 2021 17:18:46 GMT", "version": "v1" }, { "created": "Tue, 1 Mar 2022 18:25:17 GMT", "version": "v2" }, { "created": "Thu, 1 Jun 2023 12:04:41 GMT", "version": "v3" } ]
2023-06-02
[ [ "Lewandowski", "Jerzy", "" ], [ "Mäkinen", "Ilkka", "" ] ]
In this article we introduce a new operator representing the three-dimensional scalar curvature in loop quantum gravity. Our construction does not apply to the entire kinematical Hilbert space of loop quantum gravity; instead, the operator is defined on the Hilbert space of a fixed cubical graph. The starting point of ...
1709.03798
Tapobrata Sarkar
Kaushik Bhattacharya, Dipanjan Dey, Arindam Mazumdar, Tapobrata Sarkar
New class of naked singularities and their observational signatures
Substantial modifications in the results. Present version is fully re-written, and the title is also changed. 24 pages, 10 figures
null
null
null
gr-qc astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
By imposing suitable junction conditions on a space-like hyper-surface, we obtain a two-parameter family of possible static configurations from gravitational collapse. These exemplify a new class of naked singularities. We show that these admit a consistent description via a two-fluid model, one of which might be dus...
[ { "created": "Tue, 12 Sep 2017 12:19:01 GMT", "version": "v1" }, { "created": "Wed, 20 Sep 2017 14:07:14 GMT", "version": "v2" }, { "created": "Tue, 2 Jan 2018 12:07:52 GMT", "version": "v3" }, { "created": "Sat, 8 Feb 2020 12:48:52 GMT", "version": "v4" } ]
2020-02-11
[ [ "Bhattacharya", "Kaushik", "" ], [ "Dey", "Dipanjan", "" ], [ "Mazumdar", "Arindam", "" ], [ "Sarkar", "Tapobrata", "" ] ]
By imposing suitable junction conditions on a space-like hyper-surface, we obtain a two-parameter family of possible static configurations from gravitational collapse. These exemplify a new class of naked singularities. We show that these admit a consistent description via a two-fluid model, one of which might be dust....
gr-qc/9612036
Arvind Borde
Arvind Borde and Alexander Vilenkin
Singularities in Inflationary Cosmology: A Review
Plain TeX. Twelve pages, five figures (that will automatically appear if you use "dvips" to print the file)
Int.J.Mod.Phys.D5:813-824,1996
10.1142/S0218271896000497
null
gr-qc
null
We review here some recent results that show that inflationary cosmological models must contain initial singularities. We also present a new singularity theorem. The question of the initial singularity re-emerges in inflationary cosmology because inflation is known to be generically future-eternal. It is natural to a...
[ { "created": "Sun, 15 Dec 1996 00:29:07 GMT", "version": "v1" } ]
2014-11-17
[ [ "Borde", "Arvind", "" ], [ "Vilenkin", "Alexander", "" ] ]
We review here some recent results that show that inflationary cosmological models must contain initial singularities. We also present a new singularity theorem. The question of the initial singularity re-emerges in inflationary cosmology because inflation is known to be generically future-eternal. It is natural to ask...
gr-qc/9604056
null
Masayuki Tanimoto, Tatsuhiko Koike, and Akio Hosoya
Dynamics of compact homogeneous universes
32 pages with 2 figures (LaTeX with epsf macro package)
J.Math.Phys. 38 (1997) 350-368
10.1063/1.531853
TIT/HEP-322/COSMO-68
gr-qc
null
A complete description of dynamics of compact locally homogeneous universes is given, which, in particular, includes explicit calculations of Teichm\"uller deformations and careful counting of dynamical degrees of freedom. We regard each of the universes as a simply connected four dimensional spacetime with identific...
[ { "created": "Wed, 1 May 1996 09:59:26 GMT", "version": "v1" }, { "created": "Sat, 27 Jul 1996 17:04:47 GMT", "version": "v2" } ]
2009-10-28
[ [ "Tanimoto", "Masayuki", "" ], [ "Koike", "Tatsuhiko", "" ], [ "Hosoya", "Akio", "" ] ]
A complete description of dynamics of compact locally homogeneous universes is given, which, in particular, includes explicit calculations of Teichm\"uller deformations and careful counting of dynamical degrees of freedom. We regard each of the universes as a simply connected four dimensional spacetime with identificat...
gr-qc/0104035
S. Antoci
S. Antoci, D.-E. Liebscher and L. Mihich
Revisiting Weyl's calculation of the gravitational pull in Bach's two-body solution
11 pages, 2 figures. Text to appear in Classical and Quantum Gravity
Class.Quant.Grav. 18 (2001) 3463-3472
10.1088/0264-9381/18/17/307
null
gr-qc
null
When the mass of one of the two bodies tends to zero, Weyl's definition of the gravitational force in an axially symmetric, static two-body solution can be given an invariant formulation in terms of a force four-vector. The norm of this force is calculated for Bach's two-body solution, that is known to be in one-to-o...
[ { "created": "Thu, 12 Apr 2001 13:24:50 GMT", "version": "v1" }, { "created": "Wed, 25 Jul 2001 09:05:26 GMT", "version": "v2" } ]
2009-11-07
[ [ "Antoci", "S.", "" ], [ "Liebscher", "D. -E.", "" ], [ "Mihich", "L.", "" ] ]
When the mass of one of the two bodies tends to zero, Weyl's definition of the gravitational force in an axially symmetric, static two-body solution can be given an invariant formulation in terms of a force four-vector. The norm of this force is calculated for Bach's two-body solution, that is known to be in one-to-one...
gr-qc/9510033
Nicholas Landsman
N.P. Landsman (DAMTP, Cambridge)
Against the Wheeler-DeWitt equation
12 pages, LaTeX; revised version corrects treatment of open minisuperspace model. No conclusions are affected by this
Class.Quant.Grav. 12 (1995) L119-L124
10.1088/0264-9381/12/12/003
null
gr-qc
null
The ADM approach to canonical general relativity combined with Dirac's method of quantizing constrained systems leads to the Wheeler-DeWitt equation. A number of mathematical as well as physical difficulties that arise in connection with this equation may be circumvented if one employs a covariant Hamiltonian method ...
[ { "created": "Tue, 17 Oct 1995 11:12:15 GMT", "version": "v1" }, { "created": "Mon, 20 Nov 1995 13:33:10 GMT", "version": "v2" } ]
2009-10-28
[ [ "Landsman", "N. P.", "", "DAMTP, Cambridge" ] ]
The ADM approach to canonical general relativity combined with Dirac's method of quantizing constrained systems leads to the Wheeler-DeWitt equation. A number of mathematical as well as physical difficulties that arise in connection with this equation may be circumvented if one employs a covariant Hamiltonian method in...
1711.03199
Jonas Mureika
Luciano Manfredi, Jonas Mureika, John Moffat
Quasinormal Modes of Modified Gravity (MOG) Black Holes
null
Phys. Lett. B779 (2018) 492-497
10.1016/j.physletb.2017.11.006
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Quasinormal modes (QNMs) for gravitational and electromagnetic perturbations are calculated in a Scalar-Tensor-Vector (Modified Gravity) spacetime, which was initially proposed to obtain correct dynamics of galaxies and galaxy clusters without the need for dark matter. It is found that for the increasing model pa...
[ { "created": "Wed, 8 Nov 2017 22:52:59 GMT", "version": "v1" }, { "created": "Wed, 11 Apr 2018 17:02:36 GMT", "version": "v2" } ]
2018-04-18
[ [ "Manfredi", "Luciano", "" ], [ "Mureika", "Jonas", "" ], [ "Moffat", "John", "" ] ]
The Quasinormal modes (QNMs) for gravitational and electromagnetic perturbations are calculated in a Scalar-Tensor-Vector (Modified Gravity) spacetime, which was initially proposed to obtain correct dynamics of galaxies and galaxy clusters without the need for dark matter. It is found that for the increasing model para...
1005.5397
Valerio Faraoni
Valerio Faraoni (Bishop's University)
Horizons and singularity in Clifton's spherical solution of f(R) vacuum
12 pages, LaTeX, 1 figure. Written for the proceedings of the workshop "Cosmology, Quantum Vacuum and Zeta Functions" in honour of Professor Emilio Elizalde's 60th birthday, Barcelona, March 8-10, 2010,
null
10.1007/978-3-642-19760-4_16
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Due to the failure of Birkhoff's theorem, black holes in f(R) gravity theories in which an effective time-varying cosmological "constant" is present are, in general, dynamical. Clifton's exact spherical solution of R^(1+\delta) gravity, which is dynamical and describes a central object embedded in a spatially flat un...
[ { "created": "Fri, 28 May 2010 20:35:56 GMT", "version": "v1" } ]
2015-05-19
[ [ "Faraoni", "Valerio", "", "Bishop's University" ] ]
Due to the failure of Birkhoff's theorem, black holes in f(R) gravity theories in which an effective time-varying cosmological "constant" is present are, in general, dynamical. Clifton's exact spherical solution of R^(1+\delta) gravity, which is dynamical and describes a central object embedded in a spatially flat univ...
1711.11375
Gonzalo Quiroga
C. N Kozameh, J. I. Nieva, and Gonzalo D Quiroga
Spin and Center of mass comparison between the PN approach and the asymptotic formulation
null
Phys. Rev. D 98, 064005 (2018)
10.1103/PhysRevD.98.064005
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this work we analyse the similarities and differences between the equations of motion for the center of mass and intrinsic angular momentum for isolated sources of gravitational radiation obtained by two different formulations. One approach is based on the asymptotic formulation of the GR whereas the other relies ...
[ { "created": "Thu, 30 Nov 2017 13:20:36 GMT", "version": "v1" } ]
2018-09-12
[ [ "Kozameh", "C. N", "" ], [ "Nieva", "J. I.", "" ], [ "Quiroga", "Gonzalo D", "" ] ]
In this work we analyse the similarities and differences between the equations of motion for the center of mass and intrinsic angular momentum for isolated sources of gravitational radiation obtained by two different formulations. One approach is based on the asymptotic formulation of the GR whereas the other relies on...
2405.08872
Ra\'ul Carballo-Rubio
Ra\'ul Carballo-Rubio and Astrid Eichhorn
Black hole horizons must be veiled by photon spheres
10 pages, 2 figures, Honorable Mention in the Gravity Research Foundation 2024 Awards for Essays on Gravitation
null
null
null
gr-qc astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Horizons and bound photon orbits are defining features of black holes that translate into key features of black hole images. We present a purely geometric proof that spherically symmetric, isolated objects with horizons in gravity theories with null-geodesic propagation of light must display bound photon orbits formi...
[ { "created": "Tue, 14 May 2024 18:00:03 GMT", "version": "v1" } ]
2024-05-16
[ [ "Carballo-Rubio", "Raúl", "" ], [ "Eichhorn", "Astrid", "" ] ]
Horizons and bound photon orbits are defining features of black holes that translate into key features of black hole images. We present a purely geometric proof that spherically symmetric, isolated objects with horizons in gravity theories with null-geodesic propagation of light must display bound photon orbits forming...
1907.02334
Yurii Ignat'ev
Yu. G. Ignat'ev and I. A. Kokh
Qualitative and Numerical Analysis of a Cosmological Model Based on an Asymmetric Scalar Doublet with Minimal Couplings. I. Qualitative Analysis of the Model
12 pages, 2 figures, 3 references
Russian Physics Journal,Vol. 61, No. 6, 2018, pp. 1079-1092
10.1007/s11182-018-1500-9
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A qualitative analysis of a cosmological model based on the asymmetric scalar doublet classical + phantom scalar field with minimal interaction is performed. It is shown that depending on the parameters of the model, the corresponding dynamical system can have 1, 3, or 9 stationary points corresponding to attractive ...
[ { "created": "Thu, 4 Jul 2019 11:41:42 GMT", "version": "v1" } ]
2019-07-05
[ [ "Ignat'ev", "Yu. G.", "" ], [ "Kokh", "I. A.", "" ] ]
A qualitative analysis of a cosmological model based on the asymmetric scalar doublet classical + phantom scalar field with minimal interaction is performed. It is shown that depending on the parameters of the model, the corresponding dynamical system can have 1, 3, or 9 stationary points corresponding to attractive or...
1101.5401
Rahmede Christoph
Mark Hindmarsh, Daniel Litim, Christoph Rahmede
Asymptotically Safe Cosmology
8 pages; v2: explanations and references added, accepted for publication in JCAP
JCAP 1107:019,2011
10.1088/1475-7516/2011/07/019
null
gr-qc astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study quantum modifications to cosmology in a Friedmann-Robertson-Walker universe with and without scalar fields by taking the renormalisation group running of gravitational and matter couplings into account. We exploit the Bianchi identity to relate the renormalisation group scale with scale factor and derive the...
[ { "created": "Thu, 27 Jan 2011 21:37:50 GMT", "version": "v1" }, { "created": "Wed, 15 Jun 2011 13:54:33 GMT", "version": "v2" } ]
2011-07-14
[ [ "Hindmarsh", "Mark", "" ], [ "Litim", "Daniel", "" ], [ "Rahmede", "Christoph", "" ] ]
We study quantum modifications to cosmology in a Friedmann-Robertson-Walker universe with and without scalar fields by taking the renormalisation group running of gravitational and matter couplings into account. We exploit the Bianchi identity to relate the renormalisation group scale with scale factor and derive the i...
0810.2161
Chopin Soo
Chun-Yu Lin, Chopin Soo
Generalized Painlev\'e-Gullstrand metrics
Typos corrected, additional footnotes
Phys.Lett.B671:493-495,2009
10.1016/j.physletb.2008.12.051
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
An obstruction to the implementation of spatially flat Painleve-Gullstrand(PG) slicings is demonstrated, and explicitly discussed for Reissner-Nordstrom and Schwarzschild-anti-deSitter spacetimes. Generalizations of PG slicings which are not spatially flat but which remain regular at the horizons are introduced. Thes...
[ { "created": "Mon, 13 Oct 2008 13:30:16 GMT", "version": "v1" }, { "created": "Fri, 23 Jan 2009 05:12:23 GMT", "version": "v2" } ]
2009-02-02
[ [ "Lin", "Chun-Yu", "" ], [ "Soo", "Chopin", "" ] ]
An obstruction to the implementation of spatially flat Painleve-Gullstrand(PG) slicings is demonstrated, and explicitly discussed for Reissner-Nordstrom and Schwarzschild-anti-deSitter spacetimes. Generalizations of PG slicings which are not spatially flat but which remain regular at the horizons are introduced. These ...
1512.05860
Rabin Banerjee
Rabin Banerjee, Pradip Mukherjee
Comment on "Thermal Hall Effect and Geometry with Torsion"
LaTeX, 2 pages, expanded with new input
null
null
null
gr-qc cond-mat.other hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This is a comment on a paper by Gromov and Abanov [Phys. Rev. Lett. 114, 016802 (2015)]. We will show that there is an inconsistency which renders the results untenable.
[ { "created": "Fri, 18 Dec 2015 06:34:24 GMT", "version": "v1" }, { "created": "Wed, 6 Jul 2016 07:51:04 GMT", "version": "v2" } ]
2016-07-07
[ [ "Banerjee", "Rabin", "" ], [ "Mukherjee", "Pradip", "" ] ]
This is a comment on a paper by Gromov and Abanov [Phys. Rev. Lett. 114, 016802 (2015)]. We will show that there is an inconsistency which renders the results untenable.
2304.09080
Salim Shekh Dr.
S. H. Shekh, M. Muzammil, R. V. Mapari, G. U. Khapekar, A. Dixit
Holographic inflation in non-static plane symmetric space-time
15-pages; 13-figures
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The current analysis uses the non-static plane symmetric space-time to dynamically examine the holographic dark energy model as a candidates of IR cut-offs (specifically Hubble's and Granda-Oliveros cut-off). Using the Markov Chain Monte Carlo (MCMC) method, we estimate the best fit values for the model parameters im...
[ { "created": "Sun, 16 Apr 2023 09:11:37 GMT", "version": "v1" } ]
2023-04-19
[ [ "Shekh", "S. H.", "" ], [ "Muzammil", "M.", "" ], [ "Mapari", "R. V.", "" ], [ "Khapekar", "G. U.", "" ], [ "Dixit", "A.", "" ] ]
The current analysis uses the non-static plane symmetric space-time to dynamically examine the holographic dark energy model as a candidates of IR cut-offs (specifically Hubble's and Granda-Oliveros cut-off). Using the Markov Chain Monte Carlo (MCMC) method, we estimate the best fit values for the model parameters impo...
gr-qc/0509007
Andreas W. Aste
Andreas Aste, Dirk Trautmann
Radial fall of a test particle onto an evaporating black hole
6 pages, 3 figures, LATEX
Can.J.Phys. 83 (2005) 1001-1006
10.1139/p05-058
null
gr-qc
null
A test particle falling into a classical black hole crosses the event horizon and ends up in the singularity within finite eigentime. In the `more realistic' case of a `classical' evaporating black hole, an observer falling onto a black hole observes a sudden evaporation of the hole. This illustrates the fact that th...
[ { "created": "Thu, 1 Sep 2005 12:36:36 GMT", "version": "v1" } ]
2009-11-11
[ [ "Aste", "Andreas", "" ], [ "Trautmann", "Dirk", "" ] ]
A test particle falling into a classical black hole crosses the event horizon and ends up in the singularity within finite eigentime. In the `more realistic' case of a `classical' evaporating black hole, an observer falling onto a black hole observes a sudden evaporation of the hole. This illustrates the fact that the ...
1309.2670
Grasiele Batista Dos Santos
N. Pinto-Neto, G. B. Santos and W. Struyve
Quantum-to-classical transition of primordial cosmological perturbations in de Broglie-Bohm quantum theory: the bouncing scenario
5 pages, no figures, revtex4
Physical Review D 89, 023517 (2014)
10.1103/PhysRevD.89.023517
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In a previous work we have exhibited a clear description of the quantum-to-classical transition of cosmological quantum fluctuations in the inflationary scenario using the de Broglie-Bohm quantum theory. These fluctuations are believed to seed the small inhomogeneities, which are then responsible for the formation of...
[ { "created": "Tue, 10 Sep 2013 21:01:50 GMT", "version": "v1" }, { "created": "Wed, 16 Oct 2013 13:14:49 GMT", "version": "v2" } ]
2014-01-21
[ [ "Pinto-Neto", "N.", "" ], [ "Santos", "G. B.", "" ], [ "Struyve", "W.", "" ] ]
In a previous work we have exhibited a clear description of the quantum-to-classical transition of cosmological quantum fluctuations in the inflationary scenario using the de Broglie-Bohm quantum theory. These fluctuations are believed to seed the small inhomogeneities, which are then responsible for the formation of l...
1609.06358
Andrei Lebed G
Andrei G. Lebed
Breakdown of the equivalence between active gravitational mass and energy for a quantum body
4 pages
Journal of Physics: Conference Series, vol. 738, 012036 (2016)
10.1088/1742-6596/738/1/012036
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We determine active gravitational mass operator of the simplest composite quantum body - a hydrogen atom - within the semiclassical approach to the Einstein equation for a gravitational field. We show that the expectation value of the mass is equivalent to energy for stationary quantum states. On the other hand, it o...
[ { "created": "Tue, 20 Sep 2016 21:11:29 GMT", "version": "v1" } ]
2016-09-28
[ [ "Lebed", "Andrei G.", "" ] ]
We determine active gravitational mass operator of the simplest composite quantum body - a hydrogen atom - within the semiclassical approach to the Einstein equation for a gravitational field. We show that the expectation value of the mass is equivalent to energy for stationary quantum states. On the other hand, it occ...
1901.06994
Ion I. Cotaescu
Ion I. Cotaescu and Ion Cotaescu Jr
Integral representation of the scalar propagators on the de Sitter expanding universe
11 pages, 1 figure
Eur. Phys. J. C (2019) 79:671
10.1140/epjc/s10052-019-7180-y
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A new type of integral representation is proposed for the propagators of the massive Klein-Gordon field minimally coupled to the gravity of the de Sitter expanding universe. This representation encapsulates the effects of the Heaviside step functions of the Feynman propagators making possible for the first time the c...
[ { "created": "Mon, 21 Jan 2019 16:32:59 GMT", "version": "v1" }, { "created": "Wed, 23 Jan 2019 08:26:20 GMT", "version": "v2" }, { "created": "Thu, 31 Jan 2019 08:26:53 GMT", "version": "v3" }, { "created": "Thu, 6 Jun 2019 13:31:08 GMT", "version": "v4" }, { "cr...
2021-01-15
[ [ "Cotaescu", "Ion I.", "" ], [ "Cotaescu", "Ion", "Jr" ] ]
A new type of integral representation is proposed for the propagators of the massive Klein-Gordon field minimally coupled to the gravity of the de Sitter expanding universe. This representation encapsulates the effects of the Heaviside step functions of the Feynman propagators making possible for the first time the cal...
1709.06512
Amir Hadi Ziaie
Hamid Shabani and Amir Hadi Ziaie
Static Vacuum Solutions on Curved Spacetimes with Torsion
25 pages, 3 figures
Int. J. Mod. Phys. A 33 1850095 (2018)
10.1142/S0217751X18500951
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Einstein-Cartan-Kibble-Sciama ({\sf ECKS}) theory of gravity naturally extends Einstein\rq{}s general relativity ({\sf GR}) to include intrinsic angular momentum (spin) of matter. The main feature of this theory consists of an algebraic relation between spacetime torsion and spin of matter which indeed deprives t...
[ { "created": "Tue, 19 Sep 2017 16:27:44 GMT", "version": "v1" }, { "created": "Thu, 31 May 2018 21:27:24 GMT", "version": "v2" } ]
2018-06-04
[ [ "Shabani", "Hamid", "" ], [ "Ziaie", "Amir Hadi", "" ] ]
The Einstein-Cartan-Kibble-Sciama ({\sf ECKS}) theory of gravity naturally extends Einstein\rq{}s general relativity ({\sf GR}) to include intrinsic angular momentum (spin) of matter. The main feature of this theory consists of an algebraic relation between spacetime torsion and spin of matter which indeed deprives the...
2307.16161
Kemal G\"ultekin
Kemal G\"ultekin
Bose-Einstein Condensation and Black Holes in Dark Matter and Dark Energy
Ph.D thesis; 86 pages; 8 figures
null
null
null
gr-qc astro-ph.CO hep-ph hep-th
http://creativecommons.org/licenses/by/4.0/
The main aim of this study is to reveal curved space and particle physics effects on the formation of Bose-Einstein condensate (BEC) scalar fields in cosmology and around a black hole. Cosmological scalar fields for dark energy and dark matter may be considered as a result of Bose-Einstein condensation. In this regar...
[ { "created": "Sun, 30 Jul 2023 08:08:18 GMT", "version": "v1" }, { "created": "Thu, 10 Aug 2023 10:51:48 GMT", "version": "v2" } ]
2023-08-11
[ [ "Gültekin", "Kemal", "" ] ]
The main aim of this study is to reveal curved space and particle physics effects on the formation of Bose-Einstein condensate (BEC) scalar fields in cosmology and around a black hole. Cosmological scalar fields for dark energy and dark matter may be considered as a result of Bose-Einstein condensation. In this regard,...
1707.00862
Eduard Mychelkin G.
Eduard G. Mychelkin and Maxim A. Makukov
Unified geometrical basis for the generalized Ehlers identities and Raychaudhuri equations
Accepted in Reports on Mathematical Physics
null
null
null
gr-qc math-ph math.MP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It is shown that the timelike, spacelike and null versions of the Ehlers identity, as well as ensuing Raychaudhuri equations, might be all derived within a single geometrical approach based on the definition of the Riemann curvature tensor specified with respect to the corresponding congruence. Still, spacelike and n...
[ { "created": "Tue, 4 Jul 2017 09:03:01 GMT", "version": "v1" }, { "created": "Tue, 25 Jul 2017 06:32:25 GMT", "version": "v2" }, { "created": "Sat, 28 Oct 2017 13:08:58 GMT", "version": "v3" } ]
2017-10-31
[ [ "Mychelkin", "Eduard G.", "" ], [ "Makukov", "Maxim A.", "" ] ]
It is shown that the timelike, spacelike and null versions of the Ehlers identity, as well as ensuing Raychaudhuri equations, might be all derived within a single geometrical approach based on the definition of the Riemann curvature tensor specified with respect to the corresponding congruence. Still, spacelike and nul...
2408.03683
Santosh Lohakare
Santosh V Lohakare, Soumyadip Niyogi, and B. Mishra
Cosmology in Modified $f(\mathcal{G})$ Gravity: A Late Time Cosmic Phenomena
15 pages, 8 figures
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we have introduced a numerical method for solving the Friedmann equations of modified $f(\mathcal{G})$ gravity in the presence of pressureless matter, enabling us to predict the redshift behavior of the Hubble expansion rate. To evaluate the credibility of the model, we applied a Bayesian MCMC techniqu...
[ { "created": "Wed, 7 Aug 2024 10:51:09 GMT", "version": "v1" } ]
2024-08-08
[ [ "Lohakare", "Santosh V", "" ], [ "Niyogi", "Soumyadip", "" ], [ "Mishra", "B.", "" ] ]
In this paper, we have introduced a numerical method for solving the Friedmann equations of modified $f(\mathcal{G})$ gravity in the presence of pressureless matter, enabling us to predict the redshift behavior of the Hubble expansion rate. To evaluate the credibility of the model, we applied a Bayesian MCMC technique ...
2106.12050
Teodor Borislavov Vasilev
Teodor Borislavov Vasilev, Mariam Bouhmadi-L\'opez and Prado Mart\'in-Moruno
Classical and quantum $f(R)$ cosmology: The big rip, the little rip and the little sibling of the big rip
Invited review submitted to Universe for the Special Issue on "Quantum Cosmology", ed. by Prof. Paulo Vargas Moniz, 32 pages, 3 tables. v2: typos fixed, references added, matches published version
Universe 7 (2021) no.8, 288
10.3390/universe7080288
null
gr-qc astro-ph.CO hep-th
http://creativecommons.org/licenses/by/4.0/
The big rip, the little rip and the little sibling of the big rip are cosmological doomsdays predicted by some phantom dark energy models that could describe the future evolution of our Universe. When the universe evolves towards either of these future cosmic events all bounded structures and, ultimately, space-time ...
[ { "created": "Tue, 22 Jun 2021 20:14:51 GMT", "version": "v1" }, { "created": "Fri, 24 Sep 2021 13:45:02 GMT", "version": "v2" } ]
2021-09-27
[ [ "Vasilev", "Teodor Borislavov", "" ], [ "Bouhmadi-López", "Mariam", "" ], [ "Martín-Moruno", "Prado", "" ] ]
The big rip, the little rip and the little sibling of the big rip are cosmological doomsdays predicted by some phantom dark energy models that could describe the future evolution of our Universe. When the universe evolves towards either of these future cosmic events all bounded structures and, ultimately, space-time it...
1004.1505
Lorenzo Sebastiani
Olesya Gorbunova and Lorenzo Sebastiani
Viscous Fluids and Gauss-Bonnet Modified Gravity
14 pages
Gen.Rel.Grav.42:2873-2890,2010
10.1007/s10714-010-1031-3
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study effects of cosmic fluids on finite-time future singularities in modified $f(R,G)$-gravity, where $R$ and $G$ are the Ricci scalar and the Gauss-Bonnet invariant, respectively. We consider the fluid equation of state in the general form, $\omega=\omega(\rho)$, and we suppose the existence of a bulk viscosity....
[ { "created": "Fri, 9 Apr 2010 09:21:47 GMT", "version": "v1" }, { "created": "Tue, 22 Jun 2010 14:02:17 GMT", "version": "v2" }, { "created": "Fri, 12 Nov 2010 16:13:42 GMT", "version": "v3" } ]
2010-11-15
[ [ "Gorbunova", "Olesya", "" ], [ "Sebastiani", "Lorenzo", "" ] ]
We study effects of cosmic fluids on finite-time future singularities in modified $f(R,G)$-gravity, where $R$ and $G$ are the Ricci scalar and the Gauss-Bonnet invariant, respectively. We consider the fluid equation of state in the general form, $\omega=\omega(\rho)$, and we suppose the existence of a bulk viscosity. W...
1706.02354
Marek Szydlowski
Marek Szydlowski and Aleksander Stachowski
Is a pole type singularity an alternative to inflation?
RevTeX 4.1; 33 pages, 9 figures; ver. 2: new title, new part on the pole type singularities with inflation
Eur. Phys. J. C78, 552 (2018)
10.1140/epjc/s10052-018-6036-1
null
gr-qc astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we apply a method of reducing the dynamics of FRW cosmological models with the barotropic form of the equation of state to the dynamical system of the Newtonian type to detect the finite scale factor singularities and the finite-time singularities. In this approach all information concerning the dynami...
[ { "created": "Wed, 7 Jun 2017 19:29:26 GMT", "version": "v1" }, { "created": "Mon, 21 May 2018 17:26:58 GMT", "version": "v2" } ]
2019-09-27
[ [ "Szydlowski", "Marek", "" ], [ "Stachowski", "Aleksander", "" ] ]
In this paper, we apply a method of reducing the dynamics of FRW cosmological models with the barotropic form of the equation of state to the dynamical system of the Newtonian type to detect the finite scale factor singularities and the finite-time singularities. In this approach all information concerning the dynamics...
1103.3092
Kouji Nakamura
Kouji Nakamura
Alternative construction of gauge-invariant variables for linear metric perturbation on general background spacetime
8 pages, no figure
null
null
null
gr-qc astro-ph.CO hep-th math-ph math.MP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Construction of the gauge-invariant variables for the linear metric perturbation, which was proposed in the paper [K. Nakamura, arXiv:1101.1147], is discussed through an alternative approach. Our starting point of the construction of the gauge-invariant variables is an non-trivial non-local decomposition of the linea...
[ { "created": "Wed, 16 Mar 2011 04:19:46 GMT", "version": "v1" } ]
2011-03-17
[ [ "Nakamura", "Kouji", "" ] ]
Construction of the gauge-invariant variables for the linear metric perturbation, which was proposed in the paper [K. Nakamura, arXiv:1101.1147], is discussed through an alternative approach. Our starting point of the construction of the gauge-invariant variables is an non-trivial non-local decomposition of the linear ...
1705.01252
James O'Brien
James G. O'Brien, Thomas L. Chiarelli, Jeremy Dentico, Modestas Stulge, Brian Stefanski, Robert Moss and Spasen Chaykov
Alternative gravity rotation curves for the Little Things Survey
13 Pages, 7 Figures, Accepted in Astrophysical Journal
null
10.3847/1538-4357/aa99e1
null
gr-qc astro-ph.GA
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Galactic rotation curves have proven to be the testing ground for dark matter bounds in spiral galaxies of all morphologies. Dwarf galaxies serve as an increasingly interesting case of rotation curve dynamics due to their typically rising rotation curve as opposed to the flattening curve of large spirals. These galax...
[ { "created": "Wed, 3 May 2017 04:44:36 GMT", "version": "v1" }, { "created": "Wed, 6 Dec 2017 15:11:57 GMT", "version": "v2" } ]
2018-01-10
[ [ "O'Brien", "James G.", "" ], [ "Chiarelli", "Thomas L.", "" ], [ "Dentico", "Jeremy", "" ], [ "Stulge", "Modestas", "" ], [ "Stefanski", "Brian", "" ], [ "Moss", "Robert", "" ], [ "Chaykov", "Spasen", "" ...
Galactic rotation curves have proven to be the testing ground for dark matter bounds in spiral galaxies of all morphologies. Dwarf galaxies serve as an increasingly interesting case of rotation curve dynamics due to their typically rising rotation curve as opposed to the flattening curve of large spirals. These galaxie...
gr-qc/9801011
Leonid Grishchuk
L P Grishchuk
Comment on the "Influence of Cosmological Transitions on the Evolution of Density Perturbations"
15 pages, revised in connection with remarks of a neutral referee
null
null
null
gr-qc astro-ph hep-ph
null
A recent paper by Martin and Schwarz [1] argues that the ``standard inflationary result" has been finally proven. The result itself is formulated as: ``the closer the inflationary epoch is to the de Sitter space-time, the less important are large-scale gravitational waves in the CMBR today". Beginning from the basic ...
[ { "created": "Tue, 6 Jan 1998 14:58:48 GMT", "version": "v1" }, { "created": "Sat, 17 Jan 1998 17:37:53 GMT", "version": "v2" }, { "created": "Fri, 17 Sep 1999 11:27:37 GMT", "version": "v3" } ]
2007-05-23
[ [ "Grishchuk", "L P", "" ] ]
A recent paper by Martin and Schwarz [1] argues that the ``standard inflationary result" has been finally proven. The result itself is formulated as: ``the closer the inflationary epoch is to the de Sitter space-time, the less important are large-scale gravitational waves in the CMBR today". Beginning from the basic eq...
2309.02678
Muhammad Sharif
M. Sharif and K. Hassan
Analysis of Complexity Factor for Charged Dissipative Configuration in Modified Gravity
28 pages, no figure
Eur. Phys. J. Plus 138(2023)787
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we determine the electromagnetic effects on the complexity factor of radiating anisotropic cylindrical geometry in the background of $f(G,\mathcal{T})$ theory. The self-gravitating objects possessing inhomogeneous energy density, pressure anisotropy, heat flux, charge and correction terms appear to enc...
[ { "created": "Wed, 6 Sep 2023 03:12:13 GMT", "version": "v1" } ]
2023-09-07
[ [ "Sharif", "M.", "" ], [ "Hassan", "K.", "" ] ]
In this paper, we determine the electromagnetic effects on the complexity factor of radiating anisotropic cylindrical geometry in the background of $f(G,\mathcal{T})$ theory. The self-gravitating objects possessing inhomogeneous energy density, pressure anisotropy, heat flux, charge and correction terms appear to encou...
2108.07069
Daniela Pugliese Dr
D. Pugliese, Z. Stuchlik
General relativistic rotational energy extraction from black holes-accretion disk systems
Published in: Class.Quant.Grav. 38 (2021) 14, 145014
Class.Quant.Grav. 38 (2021) 14, 145014
10.1088/1361-6382/abff97
null
gr-qc astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We constrain the BHs spin with the evaluation of the dimensionless parameter \xi, the total rotational energy extracted versus the BH mass. The energy extraction can power an outflow which can be then observed. We relate the energy extraction to the accreting configurations and the accretion processes occurring in a ...
[ { "created": "Mon, 16 Aug 2021 13:03:51 GMT", "version": "v1" } ]
2021-08-17
[ [ "Pugliese", "D.", "" ], [ "Stuchlik", "Z.", "" ] ]
We constrain the BHs spin with the evaluation of the dimensionless parameter \xi, the total rotational energy extracted versus the BH mass. The energy extraction can power an outflow which can be then observed. We relate the energy extraction to the accreting configurations and the accretion processes occurring in a cl...
0810.4515
James Lindesay
James Lindesay
Quantum Behaviors on an Excreting Black Hole
33 pages, 14 figures
Class.Quant.Grav.26:125014,2009
10.1088/0264-9381/26/12/125014
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Often, geometries with horizons offer insights into the intricate relationships between general relativity and quantum physics. However, some subtle aspects of gravitating quantum systems might be difficult to ascertain using static backgrounds, since quantum mechanics incorporates dynamic measurability constraints (...
[ { "created": "Fri, 24 Oct 2008 17:39:35 GMT", "version": "v1" } ]
2009-11-19
[ [ "Lindesay", "James", "" ] ]
Often, geometries with horizons offer insights into the intricate relationships between general relativity and quantum physics. However, some subtle aspects of gravitating quantum systems might be difficult to ascertain using static backgrounds, since quantum mechanics incorporates dynamic measurability constraints (su...
2309.16107
Daniel Mata-Pacheco
H. Garcia-Compean, D. Mata-Pacheco
Scalar field inflation driven by a modification of the Heisenberg algebra
36 pages, 1 figure. All sections were improved. References added
null
10.1142/S0218271824500378
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the modifications induced on scalar field inflation produced by considering a general modification of the Heisenberg algebra. We proceed by modifying the Poisson brackets on the classical theory whenever the corresponding quantum commutator is modified. We do not restrict ourselves to a specific form for suc...
[ { "created": "Thu, 28 Sep 2023 02:18:16 GMT", "version": "v1" }, { "created": "Sun, 11 Aug 2024 16:49:45 GMT", "version": "v2" } ]
2024-08-13
[ [ "Garcia-Compean", "H.", "" ], [ "Mata-Pacheco", "D.", "" ] ]
We study the modifications induced on scalar field inflation produced by considering a general modification of the Heisenberg algebra. We proceed by modifying the Poisson brackets on the classical theory whenever the corresponding quantum commutator is modified. We do not restrict ourselves to a specific form for such ...
2103.01182
Sotirios Karamitsos
Alexandros Karam, Sotirios Karamitsos, Margus Saal
$\beta$-function reconstruction of Palatini inflationary attractors
26 pages, 2 figures
null
10.1088/1475-7516/2021/10/068
null
gr-qc astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Attractor inflation is a particularly robust framework for developing inflationary models that are insensitive to the details of the potential. Such models are most often considered in the metric formulation of gravity. However, non-minimal models may not necessarily maintain their attractor nature in the Palatini fo...
[ { "created": "Mon, 1 Mar 2021 18:27:41 GMT", "version": "v1" } ]
2021-11-03
[ [ "Karam", "Alexandros", "" ], [ "Karamitsos", "Sotirios", "" ], [ "Saal", "Margus", "" ] ]
Attractor inflation is a particularly robust framework for developing inflationary models that are insensitive to the details of the potential. Such models are most often considered in the metric formulation of gravity. However, non-minimal models may not necessarily maintain their attractor nature in the Palatini form...
2011.06932
M. Farasat Shamir
M. Farasat Shamir
Massive Compact Bardeen Stars with Conformal Motion
12 pages, 6 figures
Phys. Lett. B811(2020)135927
10.1016/j.physletb.2020.135927
null
gr-qc
http://creativecommons.org/licenses/by/4.0/
The main focus of this paper is to discuss the solutions of Einstein-Maxwell's field equations for compact stars study. We have chosen the MIT bag model equation of state for the pressure-energy density relationship and conformal Killing vectors are used to investigate the appropriate forms for metric coefficients. W...
[ { "created": "Thu, 12 Nov 2020 09:16:21 GMT", "version": "v1" } ]
2020-11-16
[ [ "Shamir", "M. Farasat", "" ] ]
The main focus of this paper is to discuss the solutions of Einstein-Maxwell's field equations for compact stars study. We have chosen the MIT bag model equation of state for the pressure-energy density relationship and conformal Killing vectors are used to investigate the appropriate forms for metric coefficients. We ...
2106.08572
Heba Sami
Heba Sami and Amare Abebe
Cosmic hierarchy in $f(R)$ gravity
15 pages and 20 figures
null
10.1142/S0219887822501675
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this contribution, we investigate hierarchical nature of large-scale structure clustering through the oscillatory nature of the solutions of the Schr\"{o}dinger-like Friedmann equation in a modified gravitational background described by the $f(R)$ gravity theory. We find the cosmological solutions to the Schr\"{o}...
[ { "created": "Wed, 16 Jun 2021 06:41:43 GMT", "version": "v1" } ]
2022-10-05
[ [ "Sami", "Heba", "" ], [ "Abebe", "Amare", "" ] ]
In this contribution, we investigate hierarchical nature of large-scale structure clustering through the oscillatory nature of the solutions of the Schr\"{o}dinger-like Friedmann equation in a modified gravitational background described by the $f(R)$ gravity theory. We find the cosmological solutions to the Schr\"{o}di...
1105.4724
Carlo Ligi
M. Bassan, B. Buonomo, G. Cavallari, E. Coccia, S. D'Antonio, V. Fafone, L.G. Foggetta, C. Ligi, A. Marini, G. Mazzitelli, G. Modestino, G. Pizzella, L. Quintieri, F. Ronga, P. Valente, S. M. Vinko
Vibrational excitation induced by electron beam and cosmic rays in normal and superconductive aluminum bars
28 pages, 13 figures
null
10.1016/j.nima.2011.08.028
null
gr-qc astro-ph.IM physics.ins-det
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We report new measurements of the acoustic excitation of an Al5056 superconductive bar when hit by an electron beam, in a previously unexplored temperature range, down to 0.35 K. These data, analyzed together with previous results of the RAP experiment obtained for T > 0.54 K, show a vibrational response enhanced by ...
[ { "created": "Tue, 24 May 2011 10:25:04 GMT", "version": "v1" }, { "created": "Tue, 2 Aug 2011 09:27:08 GMT", "version": "v2" } ]
2015-05-28
[ [ "Bassan", "M.", "" ], [ "Buonomo", "B.", "" ], [ "Cavallari", "G.", "" ], [ "Coccia", "E.", "" ], [ "D'Antonio", "S.", "" ], [ "Fafone", "V.", "" ], [ "Foggetta", "L. G.", "" ], [ "Ligi", "C.", ...
We report new measurements of the acoustic excitation of an Al5056 superconductive bar when hit by an electron beam, in a previously unexplored temperature range, down to 0.35 K. These data, analyzed together with previous results of the RAP experiment obtained for T > 0.54 K, show a vibrational response enhanced by a ...
2306.07411
D\'avid Szepessy
P. Hrask\'o, D. Szepessy
On the Absoluteness of Rotation
null
null
null
null
gr-qc
http://creativecommons.org/licenses/by/4.0/
We argue that in the general relativistic calculation of planetary orbits, the choice of a reference frame which is an obligatory condition in the Newtonian approach is replaced by an appropriate boundary condition on the solution of Einstein equation. Implications of this observation on the nature of rotation and th...
[ { "created": "Mon, 12 Jun 2023 20:38:41 GMT", "version": "v1" } ]
2023-06-14
[ [ "Hraskó", "P.", "" ], [ "Szepessy", "D.", "" ] ]
We argue that in the general relativistic calculation of planetary orbits, the choice of a reference frame which is an obligatory condition in the Newtonian approach is replaced by an appropriate boundary condition on the solution of Einstein equation. Implications of this observation on the nature of rotation and the ...
2303.08153
Charalampos Markakis
Charalampos Markakis, Sean Bray, An{\i}l Zengino\u{g}lu
Symmetric integration of the 1+1 Teukolsky equation on hyperboloidal foliations of Kerr spacetimes
28 pages, 9 figures
null
null
null
gr-qc astro-ph.HE cs.NA math.NA
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This work outlines a fast, high-precision time-domain solver for scalar, electromagnetic and gravitational perturbations on hyperboloidal foliations of Kerr space-times. Time-domain Teukolsky equation solvers have typically used explicit methods, which numerically violate Noether symmetries and are Courant-limited. T...
[ { "created": "Tue, 14 Mar 2023 18:00:28 GMT", "version": "v1" } ]
2023-03-16
[ [ "Markakis", "Charalampos", "" ], [ "Bray", "Sean", "" ], [ "Zenginoğlu", "Anıl", "" ] ]
This work outlines a fast, high-precision time-domain solver for scalar, electromagnetic and gravitational perturbations on hyperboloidal foliations of Kerr space-times. Time-domain Teukolsky equation solvers have typically used explicit methods, which numerically violate Noether symmetries and are Courant-limited. The...
1102.0016
Doron Ludwin
Doron ludwin
A Quantum Twin Paradox
9 pages, 2 figures
null
null
null
gr-qc quant-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Classical Twin Paradox is widely dealt in literature and neatly resolved. In addition, it is also well known that, when looking at two systems which are boosted relative to each other, the concept of the simultaneous effect of a quantum measurement in space-time causes some discrepancies in the cause-effect behav...
[ { "created": "Mon, 31 Jan 2011 21:25:48 GMT", "version": "v1" }, { "created": "Wed, 9 Feb 2011 10:10:43 GMT", "version": "v2" } ]
2011-02-10
[ [ "ludwin", "Doron", "" ] ]
The Classical Twin Paradox is widely dealt in literature and neatly resolved. In addition, it is also well known that, when looking at two systems which are boosted relative to each other, the concept of the simultaneous effect of a quantum measurement in space-time causes some discrepancies in the cause-effect behavio...
1001.0575
Steven L. Liebling
Steven L. Liebling, Luis Lehner, David Neilsen, Carlos Palenzuela
Evolutions of Magnetized and Rotating Neutron Stars
12 pages, 8 figures
Phys.Rev.D81:124023,2010
10.1103/PhysRevD.81.124023
null
gr-qc astro-ph.SR
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the evolution of magnetized and rigidly rotating neutron stars within a fully general relativistic implementation of ideal magnetohydrodynamics with no assumed symmetries in three spatial dimensions. The stars are modeled as rotating, magnetized polytropic stars and we examine diverse scenarios to study thei...
[ { "created": "Mon, 4 Jan 2010 21:04:58 GMT", "version": "v1" }, { "created": "Mon, 24 May 2010 20:08:42 GMT", "version": "v2" } ]
2010-08-24
[ [ "Liebling", "Steven L.", "" ], [ "Lehner", "Luis", "" ], [ "Neilsen", "David", "" ], [ "Palenzuela", "Carlos", "" ] ]
We study the evolution of magnetized and rigidly rotating neutron stars within a fully general relativistic implementation of ideal magnetohydrodynamics with no assumed symmetries in three spatial dimensions. The stars are modeled as rotating, magnetized polytropic stars and we examine diverse scenarios to study their ...
gr-qc/9510036
Dario Nunez
Dar\'io N\'u\~nez, Hernando Quevedo, and Daniel Sudarsky
How short can the hair of a black hole be?
8 pages in Latex
null
null
null
gr-qc
null
We show that in all theories in which black hole hair has been discovered, the region with non-trivial structure of the non-linear matter fields must extend beyond $3/ 2$ the horizon radius, independently of all other parameters present in the theory. We argue that this is a universal lower bound that applies in ever...
[ { "created": "Tue, 17 Oct 1995 18:27:25 GMT", "version": "v1" } ]
2016-08-15
[ [ "Núñez", "Darío", "" ], [ "Quevedo", "Hernando", "" ], [ "Sudarsky", "Daniel", "" ] ]
We show that in all theories in which black hole hair has been discovered, the region with non-trivial structure of the non-linear matter fields must extend beyond $3/ 2$ the horizon radius, independently of all other parameters present in the theory. We argue that this is a universal lower bound that applies in every ...
2005.14481
Hiroaki Tahara
Hiroaki W. H. Tahara, Tsutomu Kobayashi and Jun'ichi Yokoyama
A new mechanism for freezing extra dimensions with higher-order curvature terms
6 pages
null
10.1016/j.physletb.2020.135857
RUP-20-17, RESCEU-9/20
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We construct a model of higher dimensional cosmology in which extra dimensions are frozen by virtue of the cubic-order Lovelock gravity throughout the cosmic history from inflation to the present with radiation and matter-dominated regimes in between.
[ { "created": "Fri, 29 May 2020 09:57:30 GMT", "version": "v1" } ]
2020-10-21
[ [ "Tahara", "Hiroaki W. H.", "" ], [ "Kobayashi", "Tsutomu", "" ], [ "Yokoyama", "Jun'ichi", "" ] ]
We construct a model of higher dimensional cosmology in which extra dimensions are frozen by virtue of the cubic-order Lovelock gravity throughout the cosmic history from inflation to the present with radiation and matter-dominated regimes in between.
1506.08073
Garrett Lisi
A. Garrett Lisi
Lie Group Cosmology
42 pages, 1 figure; v2: minor corrections
null
null
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Our universe is a deforming Lie group.
[ { "created": "Wed, 24 Jun 2015 20:01:11 GMT", "version": "v1" }, { "created": "Thu, 24 Sep 2015 18:08:39 GMT", "version": "v2" } ]
2015-09-25
[ [ "Lisi", "A. Garrett", "" ] ]
Our universe is a deforming Lie group.
2207.08235
David Benisty
David Benisty
Testing modified gravity via Yukawa potential in two body problem: Analytical solution and observational constraints
Accepted for Phys Rev D
Phys Rev D 106, 043001 (2022)
10.1103/PhysRevD.106.043001
null
gr-qc astro-ph.EP hep-th
http://creativecommons.org/licenses/by/4.0/
Many alternative theories of gravity screens a Yukawa-type potential. This article shows Keplerian-type parametrization as a solution of Yukawa type potential accurate equations of motion for two non-spinning compact objects moving in an eccentric orbit. A bound from the solar system is presented.
[ { "created": "Sun, 17 Jul 2022 17:23:27 GMT", "version": "v1" } ]
2022-08-02
[ [ "Benisty", "David", "" ] ]
Many alternative theories of gravity screens a Yukawa-type potential. This article shows Keplerian-type parametrization as a solution of Yukawa type potential accurate equations of motion for two non-spinning compact objects moving in an eccentric orbit. A bound from the solar system is presented.
gr-qc/9702048
Pablo Laguna
W. Krivan, P. Laguna, P. Papadopoulos (Penn State) and N. Andersson (Wash U)
Dynamics of perturbations of rotating black holes
15 pages, 3 Postscript figures, LaTex
Phys.Rev. D56 (1997) 3395-3404
10.1103/PhysRevD.56.3395
null
gr-qc
null
We present a numerical study of the time evolution of perturbations of rotating black holes. The solutions are obtained by integrating the Teukolsky equation written as a first-order in time, coupled system of equations, in a form that explicitly captures its hyperbolic structure. We address the numerical difficultie...
[ { "created": "Mon, 24 Feb 1997 21:41:17 GMT", "version": "v1" } ]
2009-10-30
[ [ "Krivan", "W.", "", "Penn State" ], [ "Laguna", "P.", "", "Penn State" ], [ "Papadopoulos", "P.", "", "Penn State" ], [ "Andersson", "N.", "", "Wash U" ] ]
We present a numerical study of the time evolution of perturbations of rotating black holes. The solutions are obtained by integrating the Teukolsky equation written as a first-order in time, coupled system of equations, in a form that explicitly captures its hyperbolic structure. We address the numerical difficulties ...
1204.1773
Gergely Sz\'ekely
P\'eter N\'emeti and Gergely Sz\'ekely
Existence of Faster Than Light Signals Implies Hypercomputation Already in Special Relativity
14 pages, 2 figures
Lecture Notes in Computer Science Volume 7318, 2012, pp 528-538
10.1007/978-3-642-30870-3_53
null
gr-qc math.LO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Within an axiomatic framework, we investigate the possibility of hypercomputation in special relativity via faster than light signals. We formally show that hypercomputation is theoretically possible in special relativity if and only if there are faster than light signals.
[ { "created": "Mon, 9 Apr 2012 00:21:25 GMT", "version": "v1" } ]
2012-11-27
[ [ "Németi", "Péter", "" ], [ "Székely", "Gergely", "" ] ]
Within an axiomatic framework, we investigate the possibility of hypercomputation in special relativity via faster than light signals. We formally show that hypercomputation is theoretically possible in special relativity if and only if there are faster than light signals.
1406.0438
Artur Alho
Artur Alho and Claes Uggla
Global dynamics and inflationary center manifold and slow-roll approximants
32 pages, 24 figures. Appendices incorporated into main text. Matches final published version
null
10.1063/1.4906081
null
gr-qc astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider the familiar problem of a minimally coupled scalar field with quadratic potential in flat Friedmann-Lema\^itre-Robertson-Walker cosmology to illustrate a number of techniques and tools, which can be applied to a wide range of scalar field potentials and problems in e.g. modified gravity. We present a glob...
[ { "created": "Mon, 2 Jun 2014 16:36:09 GMT", "version": "v1" }, { "created": "Wed, 10 Sep 2014 18:09:04 GMT", "version": "v2" }, { "created": "Thu, 15 Jan 2015 00:08:17 GMT", "version": "v3" } ]
2015-06-19
[ [ "Alho", "Artur", "" ], [ "Uggla", "Claes", "" ] ]
We consider the familiar problem of a minimally coupled scalar field with quadratic potential in flat Friedmann-Lema\^itre-Robertson-Walker cosmology to illustrate a number of techniques and tools, which can be applied to a wide range of scalar field potentials and problems in e.g. modified gravity. We present a global...
1308.0229
Victor Shchigolev Konstantinovich
V.K. Shchigolev
Cosmological Sigma Model with Non-Minimal Coupling to the Target Space
12 pages, no figures
Cent. Eur. J. Phys., 12(1), 2014, 32-41
10.2478/s11534-014-0504-5
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A homogeneous and isotropic Universe in the framework of nonlinear sigma model with non-minimal coupling to the target space is considered. A two-component model of such a sort is preliminary investigated. Some solutions for this model are given. Perspectives and directions of development of such a sort of models are...
[ { "created": "Thu, 1 Aug 2013 14:44:41 GMT", "version": "v1" } ]
2018-02-14
[ [ "Shchigolev", "V. K.", "" ] ]
A homogeneous and isotropic Universe in the framework of nonlinear sigma model with non-minimal coupling to the target space is considered. A two-component model of such a sort is preliminary investigated. Some solutions for this model are given. Perspectives and directions of development of such a sort of models are d...
2303.16566
Felix Finster
Felix Finster, Eduardo Guendelman, Claudio F. Paganini
Modified Measures as an Effective Theory for Causal Fermion Systems
25 pages, LaTeX, 3 figures (published version)
Class. Quantum Grav. 41 (2024) 035007
10.1088/1361-6382/ad1711
null
gr-qc math-ph math.MP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We compare the structures of the theory of causal fermion systems (CFS), an approach to unify quantum theory with general relativity (GR), with those of modified measure theories (MMT), which are a set of modified gravity theories. Classical spacetimes with MMT can be obtained as the continuum limit of a CFS. This su...
[ { "created": "Wed, 29 Mar 2023 09:49:52 GMT", "version": "v1" }, { "created": "Thu, 7 Sep 2023 11:24:53 GMT", "version": "v2" }, { "created": "Tue, 19 Dec 2023 18:10:07 GMT", "version": "v3" } ]
2024-01-19
[ [ "Finster", "Felix", "" ], [ "Guendelman", "Eduardo", "" ], [ "Paganini", "Claudio F.", "" ] ]
We compare the structures of the theory of causal fermion systems (CFS), an approach to unify quantum theory with general relativity (GR), with those of modified measure theories (MMT), which are a set of modified gravity theories. Classical spacetimes with MMT can be obtained as the continuum limit of a CFS. This sugg...
1503.01956
Wen-Biao Liu
Jie-Xiong Mo, Wen-Biao Liu
Non-extended phase space thermodynamics of Lovelock AdS black holes in grand canonical ensemble
null
Eur. Phys. J. C75 (2015) 5, 211
10.1140/epjc/s10052-015-3434-5
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Recently, extended phase space thermodynamics of Lovelock AdS black holes has been of great interest. To provide insight from a different perspective and gain a unified phase transition picture, non-extended phase space thermodynamics of $(n+1)$-dimensional charged topological Lovelock AdS black holes is investigated...
[ { "created": "Fri, 6 Mar 2015 13:57:42 GMT", "version": "v1" } ]
2015-05-25
[ [ "Mo", "Jie-Xiong", "" ], [ "Liu", "Wen-Biao", "" ] ]
Recently, extended phase space thermodynamics of Lovelock AdS black holes has been of great interest. To provide insight from a different perspective and gain a unified phase transition picture, non-extended phase space thermodynamics of $(n+1)$-dimensional charged topological Lovelock AdS black holes is investigated d...
1312.2250
Mirjam Cvetic
M. Cvetic, G.W. Gibbons
Exact quasi-normal modes for the near horizon Kerr metric
4 pages
Phys. Rev. D 89, 064057 (2014)
10.1103/PhysRevD.89.064057
UPR-1257-T
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the quasi-normal modes of a massless scalar field in a general sub-extreme Kerr back- ground by exploiting the hidden SL(2, R) x SL(2, R) x SO(3) symmetry of the subtracted geometry approximation. This faithfully models the near horizon geometry but locates the black hole in a confining asymptotically conica...
[ { "created": "Sun, 8 Dec 2013 19:45:14 GMT", "version": "v1" } ]
2014-04-02
[ [ "Cvetic", "M.", "" ], [ "Gibbons", "G. W.", "" ] ]
We study the quasi-normal modes of a massless scalar field in a general sub-extreme Kerr back- ground by exploiting the hidden SL(2, R) x SL(2, R) x SO(3) symmetry of the subtracted geometry approximation. This faithfully models the near horizon geometry but locates the black hole in a confining asymptotically conical ...
1906.06691
David Benisty
David Benisty, Eduardo Guendelman, Emil Nissimov, Svetlana Pacheva
Dynamically Generated Inflation from Non-Riemannian Volume Forms
9 pages, to appear in European Physical Journal C
Eur. Phys. J. C (2019) 79: 806
10.1140/epjc/s10052-019-7310-6
null
gr-qc hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a simple modified gravity model without any initial matter fields in terms of several alternative non-Riemannian spacetime volume elements within the metric (second order) formalism. We show how the non-Riemannian volume-elements, when passing to the physical Einstein frame, create a canonical scalar field...
[ { "created": "Sun, 16 Jun 2019 14:02:01 GMT", "version": "v1" }, { "created": "Mon, 23 Sep 2019 18:46:40 GMT", "version": "v2" } ]
2019-10-02
[ [ "Benisty", "David", "" ], [ "Guendelman", "Eduardo", "" ], [ "Nissimov", "Emil", "" ], [ "Pacheva", "Svetlana", "" ] ]
We propose a simple modified gravity model without any initial matter fields in terms of several alternative non-Riemannian spacetime volume elements within the metric (second order) formalism. We show how the non-Riemannian volume-elements, when passing to the physical Einstein frame, create a canonical scalar field a...
1902.04988
Reginald Christian Bernardo
Reginald Christian Bernardo and Ian Vega
Hair-dressing Horndeski: an approach to hairy solutions in cubic Horndeski gravity
15 pages, 12 figures
Phys. Rev. D 99, 124049 (2019)
10.1103/PhysRevD.99.124049
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In obtaining exact solutions in gravitational theories containing arbitrary model functions, such as Horndeski gravity, one usually starts by prescribing the model functions of the theory and then goes on to solving their corresponding field equations. In this paper, we explore the extent to which the reverse procedu...
[ { "created": "Wed, 13 Feb 2019 16:26:49 GMT", "version": "v1" }, { "created": "Mon, 1 Apr 2019 00:59:07 GMT", "version": "v2" } ]
2019-07-02
[ [ "Bernardo", "Reginald Christian", "" ], [ "Vega", "Ian", "" ] ]
In obtaining exact solutions in gravitational theories containing arbitrary model functions, such as Horndeski gravity, one usually starts by prescribing the model functions of the theory and then goes on to solving their corresponding field equations. In this paper, we explore the extent to which the reverse procedure...
gr-qc/9805026
Thomas Baumgarte
M. Shibata, T. W. Baumgarte, and S. L. Shapiro
Stability of coalescing binary stars against gravitational collapse: hydrodynamical simulations
13 pages, 10 figures, RevTex, to appear in Phys. Rev. D
Phys.Rev.D58:023002,1998
10.1103/PhysRevD.58.023002
null
gr-qc astro-ph
null
We perform simulations of relativistic binary stars in post-Newtonian gravity to investigate their dynamical stability prior to merger against gravitational collapse in a tidal field. In general, our equations are only strictly accurate to first post-Newtonian order, but they recover full general relativity for spher...
[ { "created": "Fri, 8 May 1998 14:43:21 GMT", "version": "v1" } ]
2009-12-30
[ [ "Shibata", "M.", "" ], [ "Baumgarte", "T. W.", "" ], [ "Shapiro", "S. L.", "" ] ]
We perform simulations of relativistic binary stars in post-Newtonian gravity to investigate their dynamical stability prior to merger against gravitational collapse in a tidal field. In general, our equations are only strictly accurate to first post-Newtonian order, but they recover full general relativity for spheric...
2011.04313
Vladimir S. Manko
V. S. Manko, E. Ruiz
Equatorially symmetric configurations of two Kerr-Newman black holes
20 pages, 2 figures
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we employ the general equatorially symmetric two-soliton solution of the Einstein-Maxwell equations for elaborating two physically meaningful configurations describing a pair of equal Kerr-Newman corotating black holes separated by a massless strut. The first configuration is characterized by opposite ...
[ { "created": "Mon, 9 Nov 2020 10:38:30 GMT", "version": "v1" } ]
2020-11-10
[ [ "Manko", "V. S.", "" ], [ "Ruiz", "E.", "" ] ]
In this paper, we employ the general equatorially symmetric two-soliton solution of the Einstein-Maxwell equations for elaborating two physically meaningful configurations describing a pair of equal Kerr-Newman corotating black holes separated by a massless strut. The first configuration is characterized by opposite ma...
0907.0934
Carlo Cafaro
S. A. Ali, C. Cafaro, S. Capozziello, Ch. Corda
On the Poincare Gauge Theory of Gravitation
v2: minor changes, references added; 18 pages, no figures
Int.J.Theor.Phys.48:3426-3448,2009
10.1007/s10773-009-0149-0
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a compact, self-contained review of the conventional gauge theoretical approach to gravitation based on the local Poincare group of symmetry transformations. The covariant field equations, Bianchi identities and conservation laws for angular momentum and energy-momentum are obtained.
[ { "created": "Mon, 6 Jul 2009 08:33:46 GMT", "version": "v1" }, { "created": "Wed, 16 Dec 2009 08:52:57 GMT", "version": "v2" } ]
2010-03-25
[ [ "Ali", "S. A.", "" ], [ "Cafaro", "C.", "" ], [ "Capozziello", "S.", "" ], [ "Corda", "Ch.", "" ] ]
We present a compact, self-contained review of the conventional gauge theoretical approach to gravitation based on the local Poincare group of symmetry transformations. The covariant field equations, Bianchi identities and conservation laws for angular momentum and energy-momentum are obtained.
1705.11008
Rajibul Shaikh
Rajibul Shaikh, Sayan Kar
Gravitational lensing by scalar-tensor wormholes and the energy conditions
29 pages, 11 figures, revised version with a new section, published in PRD
Phys. Rev. D 96, 044037 (2017)
10.1103/PhysRevD.96.044037
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study gravitational lensing by a class of zero Ricci scalar wormholes which arise as solutions in a scalar-tensor theory of gravity. An attempt is made to find a possible link between lensing features, stable/unstable photon orbits and the energy conditions on the matter required to support these spacetimes. Our a...
[ { "created": "Wed, 31 May 2017 10:00:15 GMT", "version": "v1" }, { "created": "Sun, 27 Aug 2017 15:19:48 GMT", "version": "v2" } ]
2017-08-29
[ [ "Shaikh", "Rajibul", "" ], [ "Kar", "Sayan", "" ] ]
We study gravitational lensing by a class of zero Ricci scalar wormholes which arise as solutions in a scalar-tensor theory of gravity. An attempt is made to find a possible link between lensing features, stable/unstable photon orbits and the energy conditions on the matter required to support these spacetimes. Our ana...
1107.2458
Jonathan McDonald
Paul M. Alsing, Jonathan R. McDonald, Warner A. Miller
The Simplicial Ricci Tensor
19 pages, 2 figures
Class.Quant.Grav.28:155007,2011
10.1088/0264-9381/28/15/155007
null
gr-qc math.DG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Ricci tensor (Ric) is fundamental to Einstein's geometric theory of gravitation. The 3-dimensional Ric of a spacelike surface vanishes at the moment of time symmetry for vacuum spacetimes. The 4-dimensional Ric is the Einstein tensor for such spacetimes. More recently the Ric was used by Hamilton to define a non-...
[ { "created": "Wed, 13 Jul 2011 03:42:51 GMT", "version": "v1" } ]
2011-11-10
[ [ "Alsing", "Paul M.", "" ], [ "McDonald", "Jonathan R.", "" ], [ "Miller", "Warner A.", "" ] ]
The Ricci tensor (Ric) is fundamental to Einstein's geometric theory of gravitation. The 3-dimensional Ric of a spacelike surface vanishes at the moment of time symmetry for vacuum spacetimes. The 4-dimensional Ric is the Einstein tensor for such spacetimes. More recently the Ric was used by Hamilton to define a non-li...
gr-qc/0408007
Victor Tapia
Victor Tapia
Differential Invariants for Higher-Rank Tensors. A Progress Report
null
null
null
null
gr-qc
null
We outline the construction of differential invariants for higher--rank tensors.
[ { "created": "Tue, 3 Aug 2004 08:06:57 GMT", "version": "v1" } ]
2007-05-23
[ [ "Tapia", "Victor", "" ] ]
We outline the construction of differential invariants for higher--rank tensors.
2104.14258
Laur J\"arv
Laur J\"arv and Joosep Lember
Global portraits of nonminimal teleparallel inflation
22 pages, 14 plots; v2: minor typos corrected, references added, version accepted by "Universe"
Universe 2021, 7(6), 179
10.3390/universe7060179
null
gr-qc astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We construct the global phase portraits of inflationary dynamics in teleparallel gravity models with a scalar field nonminimally coupled to torsion scalar. The adopted set of variables can clearly distinguish between different asymptotic states as fixed points, including the kinetic and inflationary regimes. The key ...
[ { "created": "Thu, 29 Apr 2021 11:04:48 GMT", "version": "v1" }, { "created": "Wed, 2 Mar 2022 14:15:02 GMT", "version": "v2" } ]
2022-03-03
[ [ "Järv", "Laur", "" ], [ "Lember", "Joosep", "" ] ]
We construct the global phase portraits of inflationary dynamics in teleparallel gravity models with a scalar field nonminimally coupled to torsion scalar. The adopted set of variables can clearly distinguish between different asymptotic states as fixed points, including the kinetic and inflationary regimes. The key ro...
0810.1328
Andreas Ross
James B. Gilmore, Andreas Ross
Effective field theory calculation of second post-Newtonian binary dynamics
Replaced with published version
Phys.Rev.D78:124021,2008
10.1103/PhysRevD.78.124021
null
gr-qc hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We use the effective field theory for gravitational bound states, proposed by Goldberger and Rothstein, to compute the interaction Lagrangian of a binary system at the second Post-Newtonian order. Throughout the calculation, we use a metric parametrization based on a temporal Kaluza-Klein decomposition and test the c...
[ { "created": "Wed, 8 Oct 2008 19:35:20 GMT", "version": "v1" }, { "created": "Tue, 10 Feb 2009 23:57:04 GMT", "version": "v2" } ]
2009-02-11
[ [ "Gilmore", "James B.", "" ], [ "Ross", "Andreas", "" ] ]
We use the effective field theory for gravitational bound states, proposed by Goldberger and Rothstein, to compute the interaction Lagrangian of a binary system at the second Post-Newtonian order. Throughout the calculation, we use a metric parametrization based on a temporal Kaluza-Klein decomposition and test the cla...
1511.03933
Laur J\~Arv
Laur Jarv, Alexey Toporensky
General relativity as an attractor for scalar-torsion cosmology
8 pages, typos corrected
Phys. Rev. D 93, 024051 (2016)
10.1103/PhysRevD.93.024051
null
gr-qc astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study flat Friedmann-Lemaitre-Robertson-Walker cosmological models for a scalar field coupled nonminimally to teleparallel gravity with generic coupling and potential functions. The goal of this paper is to determine the conditions under which the cosmological evolution tends to the limit where the variation of th...
[ { "created": "Thu, 12 Nov 2015 15:48:08 GMT", "version": "v1" }, { "created": "Wed, 27 Jan 2016 18:31:07 GMT", "version": "v2" } ]
2016-08-08
[ [ "Jarv", "Laur", "" ], [ "Toporensky", "Alexey", "" ] ]
We study flat Friedmann-Lemaitre-Robertson-Walker cosmological models for a scalar field coupled nonminimally to teleparallel gravity with generic coupling and potential functions. The goal of this paper is to determine the conditions under which the cosmological evolution tends to the limit where the variation of the ...
1201.2882
John Barrow
John D. Barrow
Some Inflationary Einstein-Aether Cosmologies
10 pages, no figures
Phys. Rev. D 85, 047503 (2012)
10.1103/PhysRevD.85.047503
null
gr-qc astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show how to derive several families of accelerating universe solutions to an Einstein-Aether gravity theory. These solutions provide possible descriptions of inflationary behaviour in the early universe and late-time cosmological acceleration.
[ { "created": "Fri, 13 Jan 2012 16:13:51 GMT", "version": "v1" } ]
2015-06-03
[ [ "Barrow", "John D.", "" ] ]
We show how to derive several families of accelerating universe solutions to an Einstein-Aether gravity theory. These solutions provide possible descriptions of inflationary behaviour in the early universe and late-time cosmological acceleration.
0804.1899
Branislav Cvetkovi\'c
M. Blagojevi\'c and B. Cvetkovi\'c
Electric field in 3D gravity with torsion
LATEX, 15 pages, v2: minor corrections
Phys.Rev.D78:044036,2008
10.1103/PhysRevD.78.044036
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It is shown that in static and spherically symmetric configurations of the system of Maxwell field coupled to 3D gravity with torsion, at least one of the Maxwell field components has to vanish. Restricting our attention to the electric sector of the theory, we find an interesting exact solution, corresponding to the...
[ { "created": "Fri, 11 Apr 2008 13:51:08 GMT", "version": "v1" }, { "created": "Mon, 1 Sep 2008 11:04:40 GMT", "version": "v2" } ]
2008-11-26
[ [ "Blagojević", "M.", "" ], [ "Cvetković", "B.", "" ] ]
It is shown that in static and spherically symmetric configurations of the system of Maxwell field coupled to 3D gravity with torsion, at least one of the Maxwell field components has to vanish. Restricting our attention to the electric sector of the theory, we find an interesting exact solution, corresponding to the a...
gr-qc/9708035
Bernd Bruegmann
Bernd Bruegmann
Binary Black Hole Mergers in 3d Numerical Relativity
8 pages, 9 figures, REVTeX; expanded discussion, results unchanged
Int.J.Mod.Phys.D8:85,1999
10.1142/S0218271899000080
null
gr-qc astro-ph
null
The standard approach to the numerical evolution of black hole data using the ADM formulation with maximal slicing and vanishing shift is extended to non-symmetric black hole data containing black holes with linear momentum and spin by using a time-independent conformal rescaling based on the puncture representation ...
[ { "created": "Mon, 18 Aug 1997 19:47:22 GMT", "version": "v1" }, { "created": "Wed, 27 Aug 1997 15:07:57 GMT", "version": "v2" }, { "created": "Thu, 11 Mar 1999 08:27:40 GMT", "version": "v3" } ]
2008-11-26
[ [ "Bruegmann", "Bernd", "" ] ]
The standard approach to the numerical evolution of black hole data using the ADM formulation with maximal slicing and vanishing shift is extended to non-symmetric black hole data containing black holes with linear momentum and spin by using a time-independent conformal rescaling based on the puncture representation of...
1601.03940
Massimo Tessarotto
Massimo Tessarotto (Department of Mathematics and Geosciences, University of Trieste, Italy and Institute of Physics, Faculty of Philosophy and Science, Silesian University in Opava, Bezru\v{c}ovo n\'am.13, CZ-74601 Opava, Czech Republic) and Claudio Cremaschini (Institute of Physics, Faculty of Philosophy and ...
Theory of non-local point transformations - Part 1: Representation of Teleparallel Gravity
null
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper the extension of the functional setting customarily adopted in General Relativity (GR) is considered. For this purpose, an explicit solution of the so-called Einstein's\ Teleparallel problem is sought. This is achieved by a suitable extension of the traditional concept of GR reference frame and is based...
[ { "created": "Wed, 13 Jan 2016 07:54:01 GMT", "version": "v1" } ]
2016-01-18
[ [ "Tessarotto", "Massimo", "", "Department of Mathematics and Geosciences,\n University of Trieste, Italy and Institute of Physics, Faculty of Philosophy\n and Science, Silesian University in Opava, Bezručovo nám.13, CZ-74601\n Opava, Czech Republic" ], [ "Cremaschini", "Claudio", ...
In this paper the extension of the functional setting customarily adopted in General Relativity (GR) is considered. For this purpose, an explicit solution of the so-called Einstein's\ Teleparallel problem is sought. This is achieved by a suitable extension of the traditional concept of GR reference frame and is based o...
1706.05470
David Figueiredo
David Figueiredo, Fernando Moraes, S\'ebastien Fumeron and Bertrand Berche
Cosmology in the laboratory: an analogy between hyperbolic metamaterials and the Milne universe
12 pages, 9 figures
Phys. Rev. D 96, 105012 (2017)
10.1103/PhysRevD.96.105012
null
gr-qc cond-mat.soft
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This article shows that the compactified Milne universe geometry, a toy model for the big crunch/big bang transition, can be realized in hyperbolic metamaterials, a new class of nanoengineered systems which have recently found its way as an experimental playground for cosmological ideas. On one side, Klein-Gordon par...
[ { "created": "Sat, 17 Jun 2017 02:28:46 GMT", "version": "v1" }, { "created": "Sun, 19 Nov 2017 18:05:59 GMT", "version": "v2" } ]
2017-11-22
[ [ "Figueiredo", "David", "" ], [ "Moraes", "Fernando", "" ], [ "Fumeron", "Sébastien", "" ], [ "Berche", "Bertrand", "" ] ]
This article shows that the compactified Milne universe geometry, a toy model for the big crunch/big bang transition, can be realized in hyperbolic metamaterials, a new class of nanoengineered systems which have recently found its way as an experimental playground for cosmological ideas. On one side, Klein-Gordon parti...
2104.08851
Jacques Smulevici
Grigorios Fournodavlos, Jacques Smulevici
The initial boundary value problem in General Relativity: the umbilic case
null
null
null
null
gr-qc math.AP math.DG
http://creativecommons.org/licenses/by/4.0/
We give a short proof of local well-posedness for the initial boundary value problem in general relativity with sole boundary condition the requirement that the boundary is umbilic. This includes as a special case the totally geodesic boundary condition that we had previously addressed in [8]. The proof is based on w...
[ { "created": "Sun, 18 Apr 2021 13:25:57 GMT", "version": "v1" } ]
2021-04-20
[ [ "Fournodavlos", "Grigorios", "" ], [ "Smulevici", "Jacques", "" ] ]
We give a short proof of local well-posedness for the initial boundary value problem in general relativity with sole boundary condition the requirement that the boundary is umbilic. This includes as a special case the totally geodesic boundary condition that we had previously addressed in [8]. The proof is based on wav...
1010.0227
J. Brian Pitts
J. Brian Pitts
Massive Nordstr\"om Scalar (Density) Gravities from Universal Coupling
Forthcoming in General Relativity and Gravitation
Gen.Rel.Grav.43:871-895,2011
10.1007/s10714-010-1100-7
null
gr-qc hep-th physics.hist-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Both particle physics and the 1890s Seeliger-Neumann modification of Newtonian gravity suggest considering a "mass term" for gravity, yielding a finite range due to an exponentially decaying Yukawa potential. Unlike Nordstr\"{o}m's "massless" theory, massive scalar gravities are strictly Special Relativistic, being i...
[ { "created": "Fri, 1 Oct 2010 18:08:01 GMT", "version": "v1" } ]
2011-02-23
[ [ "Pitts", "J. Brian", "" ] ]
Both particle physics and the 1890s Seeliger-Neumann modification of Newtonian gravity suggest considering a "mass term" for gravity, yielding a finite range due to an exponentially decaying Yukawa potential. Unlike Nordstr\"{o}m's "massless" theory, massive scalar gravities are strictly Special Relativistic, being inv...
2107.07370
Rajes Ghosh
Rajes Ghosh and Sudipta Sarkar
Light rings of stationary spacetimes
5 pages, no figure
Phys. Rev. D 104, 044019 (2021)
10.1103/PhysRevD.104.044019
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a novel theorem regarding light rings in a stationary spacetime with an ergoregion. We prove that any stationary, axisymmetric, and asymptotically flat spacetime in 1 + 3 dimensions with an ergoregion must have at least one light ring outside the ergoregion. A possible extension of the proof for asymptotic...
[ { "created": "Thu, 15 Jul 2021 14:50:06 GMT", "version": "v1" } ]
2021-08-11
[ [ "Ghosh", "Rajes", "" ], [ "Sarkar", "Sudipta", "" ] ]
We present a novel theorem regarding light rings in a stationary spacetime with an ergoregion. We prove that any stationary, axisymmetric, and asymptotically flat spacetime in 1 + 3 dimensions with an ergoregion must have at least one light ring outside the ergoregion. A possible extension of the proof for asymptotical...
1209.4085
Roman Gold
Roman Gold, Bernd Bruegmann
Eccentric black hole mergers and zoom-whirl behavior from elliptic inspirals to hyperbolic encounters
19 pages, 23 figures
null
10.1103/PhysRevD.88.064051
null
gr-qc astro-ph.CO astro-ph.GA astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We perform a parameter study of non-spinning, equal and unequal mass black hole binaries on generic, eccentric orbits in numerical relativity. The linear momentum considered ranges from that of a circular orbit to ten times that value. We discuss the different manifestations of zoom-whirl behavior in the hyperbolic a...
[ { "created": "Tue, 18 Sep 2012 20:00:07 GMT", "version": "v1" } ]
2013-10-02
[ [ "Gold", "Roman", "" ], [ "Bruegmann", "Bernd", "" ] ]
We perform a parameter study of non-spinning, equal and unequal mass black hole binaries on generic, eccentric orbits in numerical relativity. The linear momentum considered ranges from that of a circular orbit to ten times that value. We discuss the different manifestations of zoom-whirl behavior in the hyperbolic and...
2306.03999
Himanshu Chaudhary
Himanshu Chaudhary, Amine Bouali, Niyaz Uddin Molla, Ujjal Debnath, G.Mustafa
Cosmological Tests of $f(R,G,\mathcal{T})$ Dark Energy Model in FRW Universe
19 pages, 10 figures; accepted for publication in EPJC
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This research article presents a new cosmological model formulated within the $f(R,G,\mathcal{T})$ framework, focusing on the observational signatures and parameter constraints of the model. The Markov Chain Monte Carlo (MCMC) technique is employed to effectively explore the parameter space using data from 36 Cosmic ...
[ { "created": "Tue, 6 Jun 2023 20:21:19 GMT", "version": "v1" }, { "created": "Thu, 28 Sep 2023 08:26:49 GMT", "version": "v2" } ]
2023-09-29
[ [ "Chaudhary", "Himanshu", "" ], [ "Bouali", "Amine", "" ], [ "Molla", "Niyaz Uddin", "" ], [ "Debnath", "Ujjal", "" ], [ "Mustafa", "G.", "" ] ]
This research article presents a new cosmological model formulated within the $f(R,G,\mathcal{T})$ framework, focusing on the observational signatures and parameter constraints of the model. The Markov Chain Monte Carlo (MCMC) technique is employed to effectively explore the parameter space using data from 36 Cosmic Ch...
gr-qc/9304035
Henri Waelbrock
Michael P. Ryan and Sergio Hojman
Non-standard phase space variables, quantization, and path integrals, or little ado about much
ICN-UNAM-93-07, 12 pages
null
null
null
gr-qc
null
Contribution to the Misner Festshrift, no abstract.
[ { "created": "Thu, 22 Apr 1993 19:39:05 GMT", "version": "v1" } ]
2007-05-23
[ [ "Ryan", "Michael P.", "" ], [ "Hojman", "Sergio", "" ] ]
Contribution to the Misner Festshrift, no abstract.
1510.03701
Clare Burrage
Philippe Brax, Clare Burrage, Anne-Christine Davis
The Speed of Galileon Gravity
17 pages, 3 figures
JCAP 1603 (2016) no.03, 004
10.1088/1475-7516/2016/03/004
null
gr-qc astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We analyse the speed of gravitational waves in coupled Galileon models with an equation of state $\omega_\phi=-1$ now and a ghost-free Minkowski limit. We find that the gravitational waves propagate much faster than the speed of light unless these models are small perturbations of cubic Galileons and the Galileon ene...
[ { "created": "Fri, 9 Oct 2015 17:14:52 GMT", "version": "v1" } ]
2016-06-21
[ [ "Brax", "Philippe", "" ], [ "Burrage", "Clare", "" ], [ "Davis", "Anne-Christine", "" ] ]
We analyse the speed of gravitational waves in coupled Galileon models with an equation of state $\omega_\phi=-1$ now and a ghost-free Minkowski limit. We find that the gravitational waves propagate much faster than the speed of light unless these models are small perturbations of cubic Galileons and the Galileon energ...
1310.7849
George E. A. Matsas
George E. A. Matsas, Raissa F. P. Mendes, and Daniel A. T. Vanzella
Reply to "Comment on `Quantum versus classical instability of scalar fields in curved backgrounds'"
2 pages
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show that the reasoning which led the author of arXiv:1310.6252 to reach his conclusions relies on an incorrect criterion for the existence of normalizable bound solutions. We reinforce that the general result derived in the Appendix of our paper (arXiv:1310.2185), namely, that "there are no tachyonic (i.e., unsta...
[ { "created": "Tue, 29 Oct 2013 15:44:46 GMT", "version": "v1" } ]
2013-10-30
[ [ "Matsas", "George E. A.", "" ], [ "Mendes", "Raissa F. P.", "" ], [ "Vanzella", "Daniel A. T.", "" ] ]
We show that the reasoning which led the author of arXiv:1310.6252 to reach his conclusions relies on an incorrect criterion for the existence of normalizable bound solutions. We reinforce that the general result derived in the Appendix of our paper (arXiv:1310.2185), namely, that "there are no tachyonic (i.e., unstabl...
1510.04957
Ra\'ul Carballo-Rubio
Carlos Barcel\'o, Ra\'ul Carballo-Rubio and Luis J. Garay
Where does the physics of extreme gravitational collapse reside?
43 pages, 1 figure. Review article with new results on the black to white hole transition. Prepared for the special issue "Open Questions in Black Hole Physics" edited by Gonzalo J. Olmo
Universe 2 (2016) no.2, 7
10.3390/universe2020007
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The gravitational collapse of massive stars serves to manifest the most severe deviations of general relativity with respect to Newtonian gravity: the formation of horizons and spacetime singularities. Both features have proven to be catalysts of deep physical developments, especially when combined with the principle...
[ { "created": "Fri, 16 Oct 2015 17:24:14 GMT", "version": "v1" } ]
2016-08-15
[ [ "Barceló", "Carlos", "" ], [ "Carballo-Rubio", "Raúl", "" ], [ "Garay", "Luis J.", "" ] ]
The gravitational collapse of massive stars serves to manifest the most severe deviations of general relativity with respect to Newtonian gravity: the formation of horizons and spacetime singularities. Both features have proven to be catalysts of deep physical developments, especially when combined with the principles ...
2112.01308
Subhajit Barman
Subhajit Barman, Dipankar Barman, Bibhas Ranjan Majhi
Entanglement harvesting from conformal vacuums between two Unruh-DeWitt detectors moving along null paths
Comments added, published in JHEP
null
10.1007/JHEP09(2022)106
null
gr-qc hep-th quant-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It is well-known that the $(1+1)$ dimensional Schwarzschild and spatially flat FLRW spacetimes are conformally flat. This work examines entanglement harvesting from the conformal field vacuums in these spacetimes between two Unruh-DeWitt detectors, moving along outgoing null trajectories. In $(1+1)$ dimensional Schwa...
[ { "created": "Thu, 2 Dec 2021 15:05:18 GMT", "version": "v1" }, { "created": "Thu, 22 Sep 2022 16:50:53 GMT", "version": "v2" } ]
2022-09-28
[ [ "Barman", "Subhajit", "" ], [ "Barman", "Dipankar", "" ], [ "Majhi", "Bibhas Ranjan", "" ] ]
It is well-known that the $(1+1)$ dimensional Schwarzschild and spatially flat FLRW spacetimes are conformally flat. This work examines entanglement harvesting from the conformal field vacuums in these spacetimes between two Unruh-DeWitt detectors, moving along outgoing null trajectories. In $(1+1)$ dimensional Schwarz...
2307.16626
Yasuyuki Hatsuda
Yasuyuki Hatsuda, Masashi Kimura
Perturbative quasinormal mode frequencies
48 pages
null
null
RUP-23-13
gr-qc hep-th
http://creativecommons.org/licenses/by/4.0/
We often encounter a situation that black hole solutions can be regarded as continuous deformations of simpler ones, or modify general relativity by continuous parameters. We develop a general framework to compute high-order perturbative corrections to quasinormal mode frequencies in such deformed problems. Our metho...
[ { "created": "Mon, 31 Jul 2023 13:04:04 GMT", "version": "v1" }, { "created": "Sat, 3 Feb 2024 02:05:31 GMT", "version": "v2" } ]
2024-02-06
[ [ "Hatsuda", "Yasuyuki", "" ], [ "Kimura", "Masashi", "" ] ]
We often encounter a situation that black hole solutions can be regarded as continuous deformations of simpler ones, or modify general relativity by continuous parameters. We develop a general framework to compute high-order perturbative corrections to quasinormal mode frequencies in such deformed problems. Our method ...