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1204.5604
Jaume Haro
Jaume de Haro
Future singularity avoidance in phantom dark energy models
Accepted for publication in JCAP
JCAP 04(07) 2012
10.1088/1475-7516/2012/07/007
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Different approaches to quantum cosmology are studied in order to deal with the future singularity avoidance problem. Our results show that these future singularities will persist but could take different forms. As an example we have studied the big rip which appear when one considers the state equation $P=\omega\rho...
[ { "created": "Wed, 25 Apr 2012 10:07:28 GMT", "version": "v1" }, { "created": "Fri, 27 Apr 2012 06:08:14 GMT", "version": "v2" }, { "created": "Mon, 11 Jun 2012 06:19:41 GMT", "version": "v3" } ]
2014-09-05
[ [ "de Haro", "Jaume", "" ] ]
Different approaches to quantum cosmology are studied in order to deal with the future singularity avoidance problem. Our results show that these future singularities will persist but could take different forms. As an example we have studied the big rip which appear when one considers the state equation $P=\omega\rho$ ...
1204.4499
N\'estor Ortiz
N\'estor Ortiz and Olivier Sarbach
Conformal diagrams for the gravitational collapse of a spherically symmetric dust cloud
8 pages, 4 figures, prepared for the proceedings of the VIII Mexican School of the Gravitational and Mathematical Physics Division of the Mexican Physical Society
AIP Conf. Proc. 1256, 349 (2010)
10.1063/1.3473876
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present an algorithm for the construction of conformal coordinates in the interior of a spherically symmetric, collapsing matter cloud in general relativity. This algorithm is based on the numerical integration of radial null geodesics. As an application we generate conformal diagrams for collapsing spherical dust...
[ { "created": "Thu, 19 Apr 2012 23:33:53 GMT", "version": "v1" } ]
2012-04-23
[ [ "Ortiz", "Néstor", "" ], [ "Sarbach", "Olivier", "" ] ]
We present an algorithm for the construction of conformal coordinates in the interior of a spherically symmetric, collapsing matter cloud in general relativity. This algorithm is based on the numerical integration of radial null geodesics. As an application we generate conformal diagrams for collapsing spherical dust c...
2007.13590
Ion I. Cotaescu
Ion I. Cotaescu
Longitudinal Doppler effect in de Sitter expanding universe
13 pages
null
10.1142/S021773232150022X
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A new redshift formula is obtained considering the longitudinal Doppler effect in the de Sitter expanding universe where the relative geodesic motion is governed by the Lorenzian isometries of our new de Sitter relativity [I. I. Cot\u aescu, {Eur. Phys. J. C} {\bf 77} (2017) 485]. This formula combines in a non-trivi...
[ { "created": "Mon, 27 Jul 2020 14:14:25 GMT", "version": "v1" }, { "created": "Tue, 28 Jul 2020 05:45:00 GMT", "version": "v2" }, { "created": "Thu, 1 Oct 2020 13:57:37 GMT", "version": "v3" } ]
2021-02-24
[ [ "Cotaescu", "Ion I.", "" ] ]
A new redshift formula is obtained considering the longitudinal Doppler effect in the de Sitter expanding universe where the relative geodesic motion is governed by the Lorenzian isometries of our new de Sitter relativity [I. I. Cot\u aescu, {Eur. Phys. J. C} {\bf 77} (2017) 485]. This formula combines in a non-trivial...
2311.03397
M.J. Luo
M.J.Luo
Local Short-Time Acceleration induced Spectral Line Broadening and Possible Implications in Cosmology
9 pages, 1 figure
null
null
null
gr-qc quant-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The paper proposes an acceleration effect that a local short-time acceleration produces an additional broadening to spectral line, while the central value of the line remains unaffected. The effect can be considered as a local and non-uniform generalization of Unruh effect. Although the acceleration-induced line broa...
[ { "created": "Sun, 5 Nov 2023 09:04:00 GMT", "version": "v1" }, { "created": "Wed, 6 Mar 2024 06:53:48 GMT", "version": "v2" } ]
2024-03-07
[ [ "Luo", "M. J.", "" ] ]
The paper proposes an acceleration effect that a local short-time acceleration produces an additional broadening to spectral line, while the central value of the line remains unaffected. The effect can be considered as a local and non-uniform generalization of Unruh effect. Although the acceleration-induced line broade...
0806.4282
Guillermo A. Gonzalez
Javier Ramos-Caro, Framsol Lopez-Suspes and Guillermo A. Gonzalez
Chaotic Motion Around Stellar Objects with Octupolar Deformation: Newtonian and Post Newtonian Approaches
Submitted to PRD
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Regular and chaotic test particle motion in gravitational fields due to stellar bodies with quadrupolar and octupolar deformation are studied using Poincare surfaces of section. In first instance, we analyze the purely Newtonian case and we find that the octupolar term induces a distortion in the KAM curves correspon...
[ { "created": "Thu, 26 Jun 2008 10:55:15 GMT", "version": "v1" } ]
2008-06-27
[ [ "Ramos-Caro", "Javier", "" ], [ "Lopez-Suspes", "Framsol", "" ], [ "Gonzalez", "Guillermo A.", "" ] ]
Regular and chaotic test particle motion in gravitational fields due to stellar bodies with quadrupolar and octupolar deformation are studied using Poincare surfaces of section. In first instance, we analyze the purely Newtonian case and we find that the octupolar term induces a distortion in the KAM curves correspondi...
1310.7894
Nelson Posada-Aguirre
Nelson C. Posada-Aguirre and Davide Batic
Electrovac Universes with a Cosmological Constant
7 pages
Cent. Eur. J. Phys. 12 (5), 297 (2014)
10.2478/s11534-014-0458-7
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present the extension of the Einstein-Maxwell system called electrovac universes by introducing a cosmological constant $\Lambda$. In the absence of the $\Lambda$ term, the crucial equation in solving the Einstein-Maxwell system is the Laplace equation. The cosmological constant modifies this equation to become in...
[ { "created": "Tue, 29 Oct 2013 17:47:30 GMT", "version": "v1" }, { "created": "Mon, 14 Apr 2014 22:50:13 GMT", "version": "v2" }, { "created": "Tue, 13 May 2014 15:59:04 GMT", "version": "v3" } ]
2020-10-05
[ [ "Posada-Aguirre", "Nelson C.", "" ], [ "Batic", "Davide", "" ] ]
We present the extension of the Einstein-Maxwell system called electrovac universes by introducing a cosmological constant $\Lambda$. In the absence of the $\Lambda$ term, the crucial equation in solving the Einstein-Maxwell system is the Laplace equation. The cosmological constant modifies this equation to become in a...
1205.4410
Oleg Zaslavskii
O. B. Zaslavskii
Energetics of particle collisions near dirty rotating extremal black holes: Banados-Silk-West effect versus Penrose process
31 pages. Final version to appear in PRD
Phys. Rev. D 86, 084030 (2012)
10.1103/PhysRevD.86.084030
null
gr-qc astro-ph.HE hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
If two particles collide near the horizon of a rotating extremal black hole, under certain conditions the energy E_{c.m.} in the center-of-mass frame can grow without limit (the so-called Banados-Silk-West effect). We consider collisions that produce two other particles. We show that for a generic dirty (surrounded b...
[ { "created": "Sun, 20 May 2012 12:13:42 GMT", "version": "v1" }, { "created": "Sat, 14 Jul 2012 08:40:53 GMT", "version": "v2" }, { "created": "Sun, 7 Oct 2012 11:55:54 GMT", "version": "v3" } ]
2015-06-05
[ [ "Zaslavskii", "O. B.", "" ] ]
If two particles collide near the horizon of a rotating extremal black hole, under certain conditions the energy E_{c.m.} in the center-of-mass frame can grow without limit (the so-called Banados-Silk-West effect). We consider collisions that produce two other particles. We show that for a generic dirty (surrounded by ...
1211.2685
Ettore Minguzzi
E. Minguzzi
Causality of spacetimes admitting a parallel null vector and weak KAM theory
68 pages, 3 figures
null
null
null
gr-qc math-ph math.MP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The causal spacetimes admitting a covariantly constant null vector provide a connection between relativistic and non-relativistic physics. We explore this relationship in several directions. We start proving a formula which relates the Lorentzian distance in the full spacetime with the least action of a mechanical sy...
[ { "created": "Mon, 12 Nov 2012 16:31:12 GMT", "version": "v1" } ]
2012-11-13
[ [ "Minguzzi", "E.", "" ] ]
The causal spacetimes admitting a covariantly constant null vector provide a connection between relativistic and non-relativistic physics. We explore this relationship in several directions. We start proving a formula which relates the Lorentzian distance in the full spacetime with the least action of a mechanical syst...
gr-qc/0403015
Sang Pyo Kim
Sang Pyo Kim (Kunsan Nat'l Univ.)
Quantum Cosmology for Tunneling Universes
RevTex4; invited talk at VI APCTP International Conference of Gravitation and Astrophysics (ICGA6), Seoul, Oct. 6-9, 2003
J.Korean Phys.Soc. 45 (2004) S172-S180
null
null
gr-qc
null
In a quantum cosmological model consisting of a Euclidean region and a Lorentzian region, Hartle-Hawking's no-bounary wave function, and Linde's wave function and Vilenkin's tunneling wave function are briefly described and compared with each other. We put a particular emphasis on semiclassical gravity from quantum c...
[ { "created": "Wed, 3 Mar 2004 00:06:50 GMT", "version": "v1" } ]
2007-05-23
[ [ "Kim", "Sang Pyo", "", "Kunsan Nat'l Univ." ] ]
In a quantum cosmological model consisting of a Euclidean region and a Lorentzian region, Hartle-Hawking's no-bounary wave function, and Linde's wave function and Vilenkin's tunneling wave function are briefly described and compared with each other. We put a particular emphasis on semiclassical gravity from quantum cos...
1310.1491
Meng-Sen Ma
Meng-Sen Ma, Ren Zhao
Phase transition and entropy spectrum of BTZ black hole in three-dimensional gravity with torsion
17 pages, 5 figures
Phys. Rev. D 89, 044005 (2014)
10.1103/PhysRevD.89.044005
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we study the phase transition and the entropy spectrum of BTZ black hole obtained in a model of three-dimensional gravity with torsion. By calculating the heat capacity we find that the BTZ black hole we considered will experience phase transition at some critical point. This indicates that the critica...
[ { "created": "Sat, 5 Oct 2013 16:28:08 GMT", "version": "v1" } ]
2014-02-12
[ [ "Ma", "Meng-Sen", "" ], [ "Zhao", "Ren", "" ] ]
In this paper, we study the phase transition and the entropy spectrum of BTZ black hole obtained in a model of three-dimensional gravity with torsion. By calculating the heat capacity we find that the BTZ black hole we considered will experience phase transition at some critical point. This indicates that the critical ...
1710.00863
Fethi M. Ramazanoglu
Fethi M Ramazano\u{g}lu
Regularization of instabilities in gravity theories
Updated version that reflects the changes in the published erratum. Conclusions are the same, but some of the missing terms in the equations are added. 6 pages
Phys. Rev. D 97, 024008 (2018)
10.1103/PhysRevD.97.024008
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate instabilities and their regularization in theories of gravitation. Instabilities can be beneficial since their growth often leads to prominent observable signatures which makes them especially relevant to relatively low signal-to-noise ratio measurements such as gravitational wave detections. An indefi...
[ { "created": "Mon, 2 Oct 2017 18:42:24 GMT", "version": "v1" }, { "created": "Wed, 17 Jan 2018 16:36:45 GMT", "version": "v2" }, { "created": "Sat, 13 Apr 2019 14:25:21 GMT", "version": "v3" } ]
2019-04-16
[ [ "Ramazanoğlu", "Fethi M", "" ] ]
We investigate instabilities and their regularization in theories of gravitation. Instabilities can be beneficial since their growth often leads to prominent observable signatures which makes them especially relevant to relatively low signal-to-noise ratio measurements such as gravitational wave detections. An indefini...
2311.03399
Alnadhief H. A. Alfedeel
Alnadhief H. A. Alfedeel, Maye Elmardi and Amare abebe
Perturbations in Bianchi Type-I spacetimes with varying Lambda, G
12 pages, 6figures
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we investigate the evolution of cosmological perturbations within the context of Bianchi Type$-I$ spacetimes. We consider models containing viscous fluids with evolving cosmological (\LL) and Newtonian gravitational (G) parameters. The investigation of how over-densities in the viscous matter content i...
[ { "created": "Sun, 5 Nov 2023 12:15:24 GMT", "version": "v1" } ]
2023-11-08
[ [ "Alfedeel", "Alnadhief H. A.", "" ], [ "Elmardi", "Maye", "" ], [ "abebe", "Amare", "" ] ]
In this paper, we investigate the evolution of cosmological perturbations within the context of Bianchi Type$-I$ spacetimes. We consider models containing viscous fluids with evolving cosmological (\LL) and Newtonian gravitational (G) parameters. The investigation of how over-densities in the viscous matter content in ...
gr-qc/0101100
Vladimir V. Dyadichev
D.V. Gal'tsov
Quantization Near Violent Singularities in Einstein-Yang-Mills Black Holes
2 pages, Contribution to the 9th Marcel Grossmann meeting (MG9), Rome, July 2000
null
10.1142/9789812777386_0251
DTP-MSU-0019
gr-qc
null
Classical singularities inside black holes in the Einstein-Yang-Mills theory exhibit unusual features. Only for discrete values of the black hole mass one encounters singularities of the Schwarzschild type (timelike) and the Reissner-Nordstrom type (spacelike). For a generic mass the approach to singularity is not sm...
[ { "created": "Fri, 26 Jan 2001 12:08:08 GMT", "version": "v1" } ]
2017-08-23
[ [ "Gal'tsov", "D. V.", "" ] ]
Classical singularities inside black holes in the Einstein-Yang-Mills theory exhibit unusual features. Only for discrete values of the black hole mass one encounters singularities of the Schwarzschild type (timelike) and the Reissner-Nordstrom type (spacelike). For a generic mass the approach to singularity is not smoo...
2203.14608
Victor Pozsgay
Victor Pozsgay
Cosmology of a new class of massive vector fields
4 pages, 2 figures, Contribution to the 2022 Cosmology session of the 56th Rencontres de Moriond
null
null
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
I introduce (Extended) Proca-Nuevo, a non-linear theory of a massive spin-1 field enjoying a non-linearly realized constraint. I will provide a covariantization scheme that allows for consistent, ghost-free cosmological solutions, describing the correct number of dynamical variables in the presence of perfect fluid m...
[ { "created": "Mon, 28 Mar 2022 09:38:51 GMT", "version": "v1" } ]
2022-03-29
[ [ "Pozsgay", "Victor", "" ] ]
I introduce (Extended) Proca-Nuevo, a non-linear theory of a massive spin-1 field enjoying a non-linearly realized constraint. I will provide a covariantization scheme that allows for consistent, ghost-free cosmological solutions, describing the correct number of dynamical variables in the presence of perfect fluid mat...
gr-qc/9907080
Moshe Carmeli
Moshe Carmeli (Ben Gurion U.)
Aspects of Cosmological Relativity
15 pages; invited talk at the Fourth Alexander Friedmann Seminar on Gravitation and Cosmology; accepted for publication in Intern. J. Theor. Phys., to appear July 1999
Int.J.Theor.Phys. 38 (1999) 1993
null
null
gr-qc astro-ph math-ph math.MP
null
We review cosmological relativity, a new special theory of relativity that was recently developed for cosmology, and discuss in detail some of its aspects.
[ { "created": "Sun, 25 Jul 1999 16:57:58 GMT", "version": "v1" } ]
2007-05-23
[ [ "Carmeli", "Moshe", "", "Ben Gurion U." ] ]
We review cosmological relativity, a new special theory of relativity that was recently developed for cosmology, and discuss in detail some of its aspects.
gr-qc/9507038
Arlen Anderson
Arlen Anderson
Evolving Constants of Motion
LaTeX, 19 pp
null
null
IFP-UNC-95-511
gr-qc
null
A critical presentation of Rovelli's ``evolving constants of motion'' is given. Previous criticisms by Kucha\v{r} concerning the role of factor ordering and the non-existence of observables are dealt with and shown to be unfounded. Kucha\v{r}'s criticisms that this approach does not solve the global, multiple choice ...
[ { "created": "Tue, 18 Jul 1995 03:19:53 GMT", "version": "v1" } ]
2007-05-23
[ [ "Anderson", "Arlen", "" ] ]
A critical presentation of Rovelli's ``evolving constants of motion'' is given. Previous criticisms by Kucha\v{r} concerning the role of factor ordering and the non-existence of observables are dealt with and shown to be unfounded. Kucha\v{r}'s criticisms that this approach does not solve the global, multiple choice or...
1212.6740
Cesar Arias H.
Cesar Arias, Rodrigo Aros and Nelson Zamorano
de Sitter Entropy from a lower dimensional black hole
Final version
Phys. Rev. D 88, 043003 (2013)
10.1103/PhysRevD.88.043003
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
An alternative method to compute the entropy of de Sitter spacetime for dimensions higher than or equal to five is presented. It is shown that de Sitter entropy may be obtained from the Bekenstein-Hawking entropy of a lower-dimensional black hole. This result follows from the existence of a one-to-one correspondence ...
[ { "created": "Sun, 30 Dec 2012 16:33:03 GMT", "version": "v1" }, { "created": "Thu, 3 Jan 2013 17:16:08 GMT", "version": "v2" }, { "created": "Tue, 4 Jun 2013 01:27:40 GMT", "version": "v3" }, { "created": "Thu, 15 Aug 2013 07:16:20 GMT", "version": "v4" } ]
2015-06-12
[ [ "Arias", "Cesar", "" ], [ "Aros", "Rodrigo", "" ], [ "Zamorano", "Nelson", "" ] ]
An alternative method to compute the entropy of de Sitter spacetime for dimensions higher than or equal to five is presented. It is shown that de Sitter entropy may be obtained from the Bekenstein-Hawking entropy of a lower-dimensional black hole. This result follows from the existence of a one-to-one correspondence be...
1109.2012
David Delphenich
D. H. Delphenich
On the topological nature of Volterra's theorem
24 pages
null
null
null
gr-qc cond-mat.mtrl-sci math-ph math.MP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It is first observed that the original formulation of the Volterra construction for dislocations and disclinations was related to the role that homotopy plays in strain compatibility, whereas the modern discussions are chiefly concerned with how it relates to the holonomy groups of connections that have non-vanishing...
[ { "created": "Fri, 9 Sep 2011 13:48:52 GMT", "version": "v1" } ]
2011-09-12
[ [ "Delphenich", "D. H.", "" ] ]
It is first observed that the original formulation of the Volterra construction for dislocations and disclinations was related to the role that homotopy plays in strain compatibility, whereas the modern discussions are chiefly concerned with how it relates to the holonomy groups of connections that have non-vanishing t...
gr-qc/0202024
Robert Beig
Robert Beig, Bernd G. Schmidt
Static, Self-Gravitating Elastic Bodies
8 pages
Proc.Roy.Soc.Lond. A459 (2003) 109-115
10.1098/rspa.2002.1031
UWThPh-2002-5
gr-qc
null
There is proved an existence theorem, in the Newtonian theory, for static, self-gravitating bodies composed of elastic material. The theorem covers the case where these bodies are small, but allows them to have arbitrary shape.
[ { "created": "Thu, 7 Feb 2002 13:27:22 GMT", "version": "v1" }, { "created": "Wed, 17 Jul 2002 13:08:00 GMT", "version": "v2" } ]
2009-11-07
[ [ "Beig", "Robert", "" ], [ "Schmidt", "Bernd G.", "" ] ]
There is proved an existence theorem, in the Newtonian theory, for static, self-gravitating bodies composed of elastic material. The theorem covers the case where these bodies are small, but allows them to have arbitrary shape.
1904.04871
Fil Simovic
Fil Simovic and Robert B. Mann
Critical Phenomena of Born-Infeld-de Sitter Black Holes in Cavities
15 pages, 18 figures
null
10.1007/JHEP05(2019)136
null
gr-qc hep-th
http://creativecommons.org/publicdomain/zero/1.0/
We examine the thermodynamic behaviour of charged, asymptotically de Sitter black holes embedded in a finite-radius isothermal cavity, with a Born-Infeld gauge field replacing the ordinary Maxwell field. We find that the non-linearities of Born-Infeld theory lead to the presence of reentrant phase transitions in the ...
[ { "created": "Tue, 9 Apr 2019 19:05:02 GMT", "version": "v1" } ]
2019-06-26
[ [ "Simovic", "Fil", "" ], [ "Mann", "Robert B.", "" ] ]
We examine the thermodynamic behaviour of charged, asymptotically de Sitter black holes embedded in a finite-radius isothermal cavity, with a Born-Infeld gauge field replacing the ordinary Maxwell field. We find that the non-linearities of Born-Infeld theory lead to the presence of reentrant phase transitions in the ca...
1003.2926
Irina Radinschi
I. Radinschi, Farook Rahaman and Asish Ghosh
On the energy of charged black holes in generalized dilaton-axion gravity
LaTex
Int.J.Theor.Phys.49:943-956,2010
10.1007/s10773-010-0273-x
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we calculate the energy distribution of some charged black holes in generalized dilaton-axion gravity. The solutions correspond to charged black holes arising in a Kalb-Ramond-dilaton background and some existing non-rotating black hole solutions are recovered in special cases. We focus our study to asy...
[ { "created": "Mon, 15 Mar 2010 14:26:17 GMT", "version": "v1" } ]
2011-01-27
[ [ "Radinschi", "I.", "" ], [ "Rahaman", "Farook", "" ], [ "Ghosh", "Asish", "" ] ]
In this paper we calculate the energy distribution of some charged black holes in generalized dilaton-axion gravity. The solutions correspond to charged black holes arising in a Kalb-Ramond-dilaton background and some existing non-rotating black hole solutions are recovered in special cases. We focus our study to asymp...
gr-qc/0503057
Rafael Sorkin
Rafael D. Sorkin
Big extra dimensions make Lambda too small
plainTeX, 9 pages, no figures To appear in a special issue of the Brazilian Journal of Physics devoted to the Proceedings of the Second International Workshop ``DICE 2004'' held September, 2004, Piombino, Italy. MOST CURRENT VERSION available at http://www.physics.syr.edu/~sorkin/some.papers/ or wherever my hom...
Braz.J.Phys. 35 (2005) 280-283
10.1590/S0103-97332005000200012
null
gr-qc hep-ph hep-th
null
I argue that the true quantum gravity scale cannot be much larger than the Planck length, because if it were then the quantum gravity-induced fluctuations in $\Lam$ would be insufficient to produce the observed cosmic ``dark energy''. If one accepts this argument, it rules out scenarios of the ``large extra dimension...
[ { "created": "Mon, 14 Mar 2005 03:07:42 GMT", "version": "v1" } ]
2015-06-25
[ [ "Sorkin", "Rafael D.", "" ] ]
I argue that the true quantum gravity scale cannot be much larger than the Planck length, because if it were then the quantum gravity-induced fluctuations in $\Lam$ would be insufficient to produce the observed cosmic ``dark energy''. If one accepts this argument, it rules out scenarios of the ``large extra dimensions'...
0903.5419
Betti Hartmann
Yves Brihaye, Thierry Caebergs (Universite de Mons, Belgium), Betti Hartmann and Momchil Minkov (Jacobs University Bremen, Germany)
Symmetry breaking in (gravitating) scalar field models describing interacting boson stars and Q-balls
33 pages including 21 figures; v2: version considerably extended: 6 new figures added, equations of motion added, discussion on varying gravitational coupling added, references added
Phys.Rev.D80:064014,2009
10.1103/PhysRevD.80.064014
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate the properties of interacting Q-balls and boson stars that sit on top of each other in great detail. The model that describes these solutions is essentially a (gravitating) two-scalar field model where both scalar fields are complex. We construct interacting Q-balls or boson stars with arbitrarily smal...
[ { "created": "Tue, 31 Mar 2009 09:48:06 GMT", "version": "v1" }, { "created": "Wed, 27 May 2009 08:48:20 GMT", "version": "v2" } ]
2009-09-25
[ [ "Brihaye", "Yves", "", "Universite de Mons, Belgium" ], [ "Caebergs", "Thierry", "", "Universite de Mons, Belgium" ], [ "Hartmann", "Betti", "", "Jacobs University Bremen, Germany" ], [ "Minkov", "Momchil", "", "Jacobs University Bremen, ...
We investigate the properties of interacting Q-balls and boson stars that sit on top of each other in great detail. The model that describes these solutions is essentially a (gravitating) two-scalar field model where both scalar fields are complex. We construct interacting Q-balls or boson stars with arbitrarily small ...
gr-qc/0111103
Mikhail Vysotsky
S.I. Blinnikov, L.B. Okun, M.I. Vysotsky (ITEP, Moscow, Russia)
Relativity and c/sqrt{3}
6 pages; PS with an essential reference added. Contribution to Holger Nielsen festschrift
null
null
null
gr-qc astro-ph physics.class-ph
null
We define the critical coordinate velocity v_c. A particle moving radially in Schwarzschild background with this velocity, v_c= c/sqrt 3, is neither accelerated, nor decelerated if gravitational field is weak, r_g << r, where r_g is the gravitational radius, while r is the current one. We find that the numerical co...
[ { "created": "Thu, 29 Nov 2001 12:19:30 GMT", "version": "v1" }, { "created": "Fri, 28 Dec 2001 10:21:32 GMT", "version": "v2" } ]
2007-05-23
[ [ "Blinnikov", "S. I.", "", "ITEP, Moscow, Russia" ], [ "Okun", "L. B.", "", "ITEP, Moscow, Russia" ], [ "Vysotsky", "M. I.", "", "ITEP, Moscow, Russia" ] ]
We define the critical coordinate velocity v_c. A particle moving radially in Schwarzschild background with this velocity, v_c= c/sqrt 3, is neither accelerated, nor decelerated if gravitational field is weak, r_g << r, where r_g is the gravitational radius, while r is the current one. We find that the numerical coinci...
1103.2475
Abhay Ashtekar
Abhay Ashtekar and David Sloan
Probability of Inflation in Loop Quantum Cosmology
34 pages, 3 figures
Gen. Rel. Grav. 43, 3619-3656 (2011)
10.1007/s10714-011-1246-y
IGC-11/03-02
gr-qc astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Inflationary models of the early universe provide a natural mechanism for the formation of large scale structure. This success brings to forefront the question of naturalness: Does a sufficiently long slow roll inflation occur generically or does it require a careful fine tuning of initial parameters? In recent years...
[ { "created": "Sat, 12 Mar 2011 20:40:02 GMT", "version": "v1" } ]
2015-05-27
[ [ "Ashtekar", "Abhay", "" ], [ "Sloan", "David", "" ] ]
Inflationary models of the early universe provide a natural mechanism for the formation of large scale structure. This success brings to forefront the question of naturalness: Does a sufficiently long slow roll inflation occur generically or does it require a careful fine tuning of initial parameters? In recent years t...
gr-qc/0609040
Winston Fairbairn
Winston Fairbairn (CPT)
Fermions in three-dimensional spinfoam quantum gravity
40 pages, 3 figures, version accepted for publication in GERG
Gen.Rel.Grav.39:427-476,2007
10.1007/s10714-006-0395-x
null
gr-qc
null
We study the coupling of massive fermions to the quantum mechanical dynamics of spacetime emerging from the spinfoam approach in three dimensions. We first recall the classical theory before constructing a spinfoam model of quantum gravity coupled to spinors. The technique used is based on a finite expansion in inver...
[ { "created": "Tue, 12 Sep 2006 12:15:59 GMT", "version": "v1" }, { "created": "Fri, 22 Dec 2006 21:14:24 GMT", "version": "v2" } ]
2008-11-26
[ [ "Fairbairn", "Winston", "", "CPT" ] ]
We study the coupling of massive fermions to the quantum mechanical dynamics of spacetime emerging from the spinfoam approach in three dimensions. We first recall the classical theory before constructing a spinfoam model of quantum gravity coupled to spinors. The technique used is based on a finite expansion in inverse...
1311.1751
Arman Tursunov
Arman Tursunov, Martin Kolo\v{s}, Ahmadjon Abdujabbarov, Bobomurat Ahmedov and Zden\v{e}k Stuchl\'ik
Acceleration of particles in spacetimes of black string
20 pages, 20 figures, 2 tables
Phys. Rev. D 88, 124001 (2013)
10.1103/PhysRevD.88.124001
null
gr-qc astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The particle acceleration mechanism in $S^2 \times\mathbb{R}^1$ topology, namely in the spacetime of the five-dimensional compact black string has been studied. The expression of center-of-mass energy of the colliding neutral particles near static black string has been found. The collision of charged particle moving ...
[ { "created": "Thu, 7 Nov 2013 17:15:38 GMT", "version": "v1" }, { "created": "Tue, 19 Nov 2013 19:09:18 GMT", "version": "v2" }, { "created": "Wed, 11 Dec 2013 14:00:57 GMT", "version": "v3" } ]
2014-10-22
[ [ "Tursunov", "Arman", "" ], [ "Kološ", "Martin", "" ], [ "Abdujabbarov", "Ahmadjon", "" ], [ "Ahmedov", "Bobomurat", "" ], [ "Stuchlík", "Zdeněk", "" ] ]
The particle acceleration mechanism in $S^2 \times\mathbb{R}^1$ topology, namely in the spacetime of the five-dimensional compact black string has been studied. The expression of center-of-mass energy of the colliding neutral particles near static black string has been found. The collision of charged particle moving at...
2011.07037
Daniela Saadeh
Jonathan Braden, Clare Burrage, Benjamin Elder, Daniela Saadeh
$\varphi$enics: Vainshtein screening with the finite element method
47 pages, 15 figures, v2: minor modifications to match version accepted by JCAP
JCAP 03 (2021) 010
10.1088/1475-7516/2021/03/010
null
gr-qc astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Within the landscape of modified theories of gravity, progress in understanding the behaviour of, and developing tests for, screening mechanisms has been hindered by the complexity of the field equations involved, which are nonlinear in nature and characterised by a large hierarchy of scales. This is especially true ...
[ { "created": "Fri, 13 Nov 2020 17:57:32 GMT", "version": "v1" }, { "created": "Tue, 30 Mar 2021 00:09:25 GMT", "version": "v2" } ]
2021-03-31
[ [ "Braden", "Jonathan", "" ], [ "Burrage", "Clare", "" ], [ "Elder", "Benjamin", "" ], [ "Saadeh", "Daniela", "" ] ]
Within the landscape of modified theories of gravity, progress in understanding the behaviour of, and developing tests for, screening mechanisms has been hindered by the complexity of the field equations involved, which are nonlinear in nature and characterised by a large hierarchy of scales. This is especially true of...
1103.2890
Bijan Saha Dr.
Bijan Saha
Nonlinear Spinor Fields and its role in Cosmology
22 pages, 12 Figures
Int. J. Theor. Phys., 51 (2012) 1812 - 1837
10.1007/s10773-011-1059-5
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Different characteristic of matter influencing the evolution of the Universe has been simulated by means of a nonlinear spinor field. Exploiting the spinor description of perfect fluid and dark energy evolution of the Universe given by an anisotropic Bianchi type-VI, VI$_0$, V, III, I or isotropic Friedmann-Robertson...
[ { "created": "Tue, 15 Mar 2011 12:08:58 GMT", "version": "v1" } ]
2015-05-01
[ [ "Saha", "Bijan", "" ] ]
Different characteristic of matter influencing the evolution of the Universe has been simulated by means of a nonlinear spinor field. Exploiting the spinor description of perfect fluid and dark energy evolution of the Universe given by an anisotropic Bianchi type-VI, VI$_0$, V, III, I or isotropic Friedmann-Robertson-W...
gr-qc/9511023
Jorma Louko
Jorma Louko and Rafael D. Sorkin
Complex actions in two-dimensional topology change
34 pages, REVTeX v3.0. (Presentational reorganization; core results unchanged.)
Class.Quant.Grav. 14 (1997) 179-204
10.1088/0264-9381/14/1/018
SU-GP-95-5-1, WISC-MILW-95-TH-16, PP96-40
gr-qc hep-th
null
We investigate topology change in (1+1) dimensions by analyzing the scalar-curvature action $1/2 \int R dV$ at the points of metric-degeneration that (with minor exceptions) any nontrivial Lorentzian cobordism necessarily possesses. In two dimensions any cobordism can be built up as a combination of only two elementa...
[ { "created": "Mon, 6 Nov 1995 23:30:22 GMT", "version": "v1" }, { "created": "Fri, 17 Nov 1995 22:46:58 GMT", "version": "v2" }, { "created": "Tue, 7 Jan 1997 16:39:14 GMT", "version": "v3" } ]
2009-10-28
[ [ "Louko", "Jorma", "" ], [ "Sorkin", "Rafael D.", "" ] ]
We investigate topology change in (1+1) dimensions by analyzing the scalar-curvature action $1/2 \int R dV$ at the points of metric-degeneration that (with minor exceptions) any nontrivial Lorentzian cobordism necessarily possesses. In two dimensions any cobordism can be built up as a combination of only two elementary...
2207.05355
Timothy Budd
Timothy Budd, Alicia Castro
Scale-invariant random geometry from mating of trees: a numerical study
28 pages, 16 figures
null
10.1103/PhysRevD.107.026010
null
gr-qc hep-th math-ph math.MP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The search for scale-invariant random geometries is central to the Asymptotic Safety hypothesis for the Euclidean path integral in quantum gravity. In an attempt to uncover new universality classes of scale-invariant random geometries that go beyond surface topology, we explore a generalization of the mating of trees...
[ { "created": "Tue, 12 Jul 2022 07:40:52 GMT", "version": "v1" } ]
2023-01-25
[ [ "Budd", "Timothy", "" ], [ "Castro", "Alicia", "" ] ]
The search for scale-invariant random geometries is central to the Asymptotic Safety hypothesis for the Euclidean path integral in quantum gravity. In an attempt to uncover new universality classes of scale-invariant random geometries that go beyond surface topology, we explore a generalization of the mating of trees a...
gr-qc/0305016
Pantelis S. Apostolopoulos
Pantelis S. Apostolopoulos and Michael Tsamparlis
Note on Matter Collineations in Kantowski-Sachs, Bianchi Types I and III Spacetimes
10 pages, Latex. Accepted for publication in General Relativity and Gravitation
Gen.Rel.Grav. 35 (2003) 1869-1876
10.1023/A:1026026517034
null
gr-qc
null
We show that the classification of Kantowski-Sachs, Bianchi Types I and III spacetimes admitting Matter Collineations (MCs) presented in a recent paper by Camci et al. [Camci, U., and Sharif, M. {Matter Collineations in Kantowski-Sachs, Bianchi Types I and III Spacetimes}, 2003 Gen. Relativ. Grav. vol. 35, 97-109] is...
[ { "created": "Sun, 4 May 2003 16:23:19 GMT", "version": "v1" } ]
2015-06-25
[ [ "Apostolopoulos", "Pantelis S.", "" ], [ "Tsamparlis", "Michael", "" ] ]
We show that the classification of Kantowski-Sachs, Bianchi Types I and III spacetimes admitting Matter Collineations (MCs) presented in a recent paper by Camci et al. [Camci, U., and Sharif, M. {Matter Collineations in Kantowski-Sachs, Bianchi Types I and III Spacetimes}, 2003 Gen. Relativ. Grav. vol. 35, 97-109] is i...
1607.04353
Dongfeng Gao
Dongfeng Gao and Mingsheng Zhan
Constraining the generalized uncertainty principle with cold atoms
null
Phys. Rev. A 94, 013607 (2016)
10.1103/PhysRevA.94.013607
null
gr-qc physics.atom-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Various theories of quantum gravity predict the existence of a minimum length scale, which implies the Planck-scale modifications of the Heisenberg uncertainty principle to a so-called generalized uncertainty principle (GUP). Previous studies of the GUP focused on its implications for high-energy physics, cosmology, ...
[ { "created": "Fri, 15 Jul 2016 01:17:58 GMT", "version": "v1" } ]
2017-04-28
[ [ "Gao", "Dongfeng", "" ], [ "Zhan", "Mingsheng", "" ] ]
Various theories of quantum gravity predict the existence of a minimum length scale, which implies the Planck-scale modifications of the Heisenberg uncertainty principle to a so-called generalized uncertainty principle (GUP). Previous studies of the GUP focused on its implications for high-energy physics, cosmology, an...
gr-qc/0102100
Nils Andersson
K Glampedakis and N Andersson
Scattering of scalar waves by rotating black holes
Revtex, 15 eps figures
Class.Quant.Grav. 18 (2001) 1939-1966
10.1088/0264-9381/18/10/309
null
gr-qc
null
We study the scattering of massless scalar waves by a Kerr black hole by letting plane monochromatic waves impinge on the black hole. We calculate the relevant scattering phase-shifts using the Pruefer phase-function method, which is computationally efficient and reliable also for high frequencies and/or large valu...
[ { "created": "Thu, 22 Feb 2001 16:25:46 GMT", "version": "v1" } ]
2016-08-31
[ [ "Glampedakis", "K", "" ], [ "Andersson", "N", "" ] ]
We study the scattering of massless scalar waves by a Kerr black hole by letting plane monochromatic waves impinge on the black hole. We calculate the relevant scattering phase-shifts using the Pruefer phase-function method, which is computationally efficient and reliable also for high frequencies and/or large values o...
1704.03251
Shinya Tomizawa
Takashi Mishima, Shinya Tomizawa
Construction and application of variations on the cylindrical gravitational waves of Weber, Wheeler, and Bonnor
33 pages, 15 figures, the figures have been displayed, to be published for Phys.Rev.D
Phys. Rev. D 96, 024023 (2017)
10.1103/PhysRevD.96.024023
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
To clarify certain nonlinear properties of strong gravitational field, we investigate cylindrically symmetric gravitational waves that are localized as regular wave packets in the space of radial and time coordinates. The waves are constructed by applying a certain kind of harmonic mapping method to the seed solution...
[ { "created": "Tue, 11 Apr 2017 11:52:06 GMT", "version": "v1" }, { "created": "Wed, 12 Apr 2017 10:45:17 GMT", "version": "v2" }, { "created": "Thu, 13 Apr 2017 07:00:03 GMT", "version": "v3" }, { "created": "Thu, 29 Jun 2017 01:51:34 GMT", "version": "v4" } ]
2017-07-19
[ [ "Mishima", "Takashi", "" ], [ "Tomizawa", "Shinya", "" ] ]
To clarify certain nonlinear properties of strong gravitational field, we investigate cylindrically symmetric gravitational waves that are localized as regular wave packets in the space of radial and time coordinates. The waves are constructed by applying a certain kind of harmonic mapping method to the seed solutions ...
1509.03830
Krzysztof Urbanowski
K. Urbanowski
Multiverse as an ensemble of stable and unstable Universes
LaTeX2e, 31 pages, 2 figures, new comments and references added
null
null
null
gr-qc hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Estimates of the Higgs and top quark masses, $m_{H} \simeq 125.10 \pm 0.14$ [GeV] and $m_{t} \simeq 172.76 \pm 0.30$ [GeV] based on the experimental results place the Standard Model in the region of the metastable vacuum. A consequence of the metastability of the Higgs vacuum is that it should induce the decay of the...
[ { "created": "Sun, 13 Sep 2015 09:44:40 GMT", "version": "v1" }, { "created": "Fri, 3 Feb 2023 17:23:07 GMT", "version": "v2" } ]
2023-02-06
[ [ "Urbanowski", "K.", "" ] ]
Estimates of the Higgs and top quark masses, $m_{H} \simeq 125.10 \pm 0.14$ [GeV] and $m_{t} \simeq 172.76 \pm 0.30$ [GeV] based on the experimental results place the Standard Model in the region of the metastable vacuum. A consequence of the metastability of the Higgs vacuum is that it should induce the decay of the e...
1306.4792
Kuantay Boshkayev
Donato Bini, Kuantay Boshkayev, Remo Ruffini, and Ivan Siutsou
Equatorial Circular Geodesics in the Hartle-Thorne Spacetime
6 pages, 8 figures, published in the proceedings of the 12th Italian-Korean Sympothium on Relativistic Astrophysics
Il Nuovo Cimento vol. 36 C, N. 1 Suppl. 1, 2013
10.1393/ncc/i2013-11483-8
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate the influence of the quadrupole moment of a rotating source on the motion of a test particle in the strong field regime. For this purpose the Hartle-Thorne metric, that is an approximate solution of vacuum Einstein field equations that describes the exterior of any slowly rotating, stationary and axial...
[ { "created": "Thu, 20 Jun 2013 09:00:34 GMT", "version": "v1" } ]
2013-06-21
[ [ "Bini", "Donato", "" ], [ "Boshkayev", "Kuantay", "" ], [ "Ruffini", "Remo", "" ], [ "Siutsou", "Ivan", "" ] ]
We investigate the influence of the quadrupole moment of a rotating source on the motion of a test particle in the strong field regime. For this purpose the Hartle-Thorne metric, that is an approximate solution of vacuum Einstein field equations that describes the exterior of any slowly rotating, stationary and axially...
gr-qc/0611150
Francisco Lobo
Francisco S. N. Lobo
Traversable wormholes supported by cosmic accelerated expanding equations of state
3 pages, contribution to the proceedings of MG11, Berlin, 23-29 July, 2006; based on an invited talk in the parallel session GT5, Wormholes, Energy Conditions and Time Machines
null
null
null
gr-qc
null
We explore the possibility that traversable wormholes be supported by specific equations of state responsible for the present accelerated expansion of the Universe, namely, phantom energy, the generalized Chaplygin gas, and the van der Waals quintessence equation of state.
[ { "created": "Wed, 29 Nov 2006 10:09:54 GMT", "version": "v1" } ]
2007-05-23
[ [ "Lobo", "Francisco S. N.", "" ] ]
We explore the possibility that traversable wormholes be supported by specific equations of state responsible for the present accelerated expansion of the Universe, namely, phantom energy, the generalized Chaplygin gas, and the van der Waals quintessence equation of state.
gr-qc/0502104
Choquet-Bruhat
Y. Choquet-Bruhat, J. Isenberg, and V. Moncrief
Topologically general U(1) symmetric Einstein spacetimes with AVTD behavior
proceedings of conference in Elba to appear in Nuovo Cimento
Nuovo Cim.B119:625-638,2004
10.1393/ncb/i2004-10174-x
null
gr-qc
null
We use Fuchsian methods to show that, for any two dimensional manifold $\Sigma^2$, there is a large family of U(1) symmetric solutions of the vacuum Einstein equations on the manifold $\Sigma \times S^1 \times \mathbb{R}$, each of which has AVTD behavior in the neighborhood of its singularity.
[ { "created": "Thu, 24 Feb 2005 17:16:50 GMT", "version": "v1" } ]
2010-11-11
[ [ "Choquet-Bruhat", "Y.", "" ], [ "Isenberg", "J.", "" ], [ "Moncrief", "V.", "" ] ]
We use Fuchsian methods to show that, for any two dimensional manifold $\Sigma^2$, there is a large family of U(1) symmetric solutions of the vacuum Einstein equations on the manifold $\Sigma \times S^1 \times \mathbb{R}$, each of which has AVTD behavior in the neighborhood of its singularity.
1910.12071
Polina Petryakova
P. M. Petryakova, S. G. Rubin
Local temperature distribution in the vicinity of gravitationally bound objects in the expanding Universe
null
Physics of Atomic Nuclei 84, 2021
10.1134/S1063778821090271
null
gr-qc
http://creativecommons.org/licenses/by-nc-sa/4.0/
We consider a cluster of Primordial Black Holes which is decoupled from the cosmological expansion (Hubble flow) and this region is heated as compared to the surrounding matter. The increased temperature inside the region can be explained by several mechanisms of Primordial Black Holes formation. We study the tempera...
[ { "created": "Sat, 26 Oct 2019 14:23:49 GMT", "version": "v1" }, { "created": "Sun, 27 Feb 2022 12:12:27 GMT", "version": "v2" } ]
2022-04-08
[ [ "Petryakova", "P. M.", "" ], [ "Rubin", "S. G.", "" ] ]
We consider a cluster of Primordial Black Holes which is decoupled from the cosmological expansion (Hubble flow) and this region is heated as compared to the surrounding matter. The increased temperature inside the region can be explained by several mechanisms of Primordial Black Holes formation. We study the temperatu...
2005.06271
Hooman Moradpour
H. Moradpour, A. H. Ziaie, M. Kord Zangeneh
Generalized entropies and corresponding holographic dark energy models
null
EPJC (2020)
10.1140/epjc/s10052-020-8307-x
80,732
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Using Tsallis statistics and its relation with Boltzmann entropy, the Tsallis entropy content of black holes is achieved, a result in full agreement with a recent study (Phys. Lett. B 794, 24 (2019)). In addition, employing Kaniadakis statistics and its relation with that of Tsallis, the Kaniadakis entropy of black h...
[ { "created": "Tue, 12 May 2020 07:33:39 GMT", "version": "v1" } ]
2020-08-18
[ [ "Moradpour", "H.", "" ], [ "Ziaie", "A. H.", "" ], [ "Zangeneh", "M. Kord", "" ] ]
Using Tsallis statistics and its relation with Boltzmann entropy, the Tsallis entropy content of black holes is achieved, a result in full agreement with a recent study (Phys. Lett. B 794, 24 (2019)). In addition, employing Kaniadakis statistics and its relation with that of Tsallis, the Kaniadakis entropy of black hol...
2109.09638
Ding Jia
Ding Jia
Time-space duality in 2D quantum gravity
matches well published version
Class. Quantum Grav. 39, 035016 (2022)
10.1088/1361-6382/ac4615
null
gr-qc hep-lat hep-th quant-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
An important task faced by all approaches of quantum gravity is to incorporate superpositions and quantify quantum uncertainties of spacetime causal relations. We address this task in 2D. By identifying a global $Z_2$ symmetry of 1+1D quantum gravity, we show that gravitational path integral configurations come in eq...
[ { "created": "Mon, 20 Sep 2021 15:45:48 GMT", "version": "v1" }, { "created": "Tue, 1 Mar 2022 21:03:09 GMT", "version": "v2" } ]
2022-03-03
[ [ "Jia", "Ding", "" ] ]
An important task faced by all approaches of quantum gravity is to incorporate superpositions and quantify quantum uncertainties of spacetime causal relations. We address this task in 2D. By identifying a global $Z_2$ symmetry of 1+1D quantum gravity, we show that gravitational path integral configurations come in equa...
gr-qc/0310124
James Shifflett
J. A. Shifflett
Einstein-Schrodinger theory in the presence of zero-point fluctuations
33 pages, latex2e, many changes, changed to geometrized units
null
null
null
gr-qc
null
The Einstein-Schrodinger theory is modified by adding a cosmological constant contribution caused by zero-point fluctuations. This cosmological constant which multiplies the symmetric metric is assumed to be nearly cancelled by Schrodinger's ``bare'' cosmological constant which multiplies the nonsymmetric fundamental...
[ { "created": "Wed, 29 Oct 2003 23:21:08 GMT", "version": "v1" }, { "created": "Fri, 31 Oct 2003 14:20:10 GMT", "version": "v2" }, { "created": "Sun, 2 Nov 2003 00:38:55 GMT", "version": "v3" }, { "created": "Mon, 17 Nov 2003 15:17:50 GMT", "version": "v4" }, { "cr...
2007-05-23
[ [ "Shifflett", "J. A.", "" ] ]
The Einstein-Schrodinger theory is modified by adding a cosmological constant contribution caused by zero-point fluctuations. This cosmological constant which multiplies the symmetric metric is assumed to be nearly cancelled by Schrodinger's ``bare'' cosmological constant which multiplies the nonsymmetric fundamental t...
1210.6889
Ivan Booth
Ivan Booth, David Wenjie Tian
Some spacetimes containing non-rotating extremal isolated horizons
15 pages, 1 figure. V2: significant revision with compression and (hopefully) clarification of presentation, one appendix removed. Ultimate results are unchanged
Class.Quant.Grav. 30 (2013) 145008
10.1088/0264-9381/30/14/145008
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Well-known results demonstrate the uniqueness of extremal isolated horizons (equivalently near-horizon spacetimes) in (3+1)-dimensions. This paper briefly reviews some of these results and then explicitly constructs families of non-asymptotically flat, non-spherically symmetric spacetimes that nevertheless contain sp...
[ { "created": "Thu, 25 Oct 2012 16:10:40 GMT", "version": "v1" }, { "created": "Tue, 30 Apr 2013 14:27:31 GMT", "version": "v2" } ]
2013-12-12
[ [ "Booth", "Ivan", "" ], [ "Tian", "David Wenjie", "" ] ]
Well-known results demonstrate the uniqueness of extremal isolated horizons (equivalently near-horizon spacetimes) in (3+1)-dimensions. This paper briefly reviews some of these results and then explicitly constructs families of non-asymptotically flat, non-spherically symmetric spacetimes that nevertheless contain sphe...
0711.1790
J. Fernando Barbero G.
J. Fernando Barbero G., Daniel G\'omez Vergel, Eduardo J. S. Villase\~nor
Quantum unitary evolution of linearly polarized S^1\times S^2 and S^3 Gowdy models coupled to massless scalar fields
Final version to appear in Classical and Quantum Gravity
Class.Quant.Grav.25:085002,2008
10.1088/0264-9381/25/8/085002
null
gr-qc
null
The purpose of this paper is to study in detail the problem of defining unitary evolution for linearly polarized S^1 x S^2 and S^3 Gowdy models (in vacuum or coupled to massless scalar fields). We show that in the Fock quantizations of these systems no choice of acceptable complex structure leads to a unitary evoluti...
[ { "created": "Mon, 12 Nov 2007 14:51:19 GMT", "version": "v1" }, { "created": "Tue, 26 Feb 2008 18:48:54 GMT", "version": "v2" } ]
2008-11-26
[ [ "G.", "J. Fernando Barbero", "" ], [ "Vergel", "Daniel Gómez", "" ], [ "Villaseñor", "Eduardo J. S.", "" ] ]
The purpose of this paper is to study in detail the problem of defining unitary evolution for linearly polarized S^1 x S^2 and S^3 Gowdy models (in vacuum or coupled to massless scalar fields). We show that in the Fock quantizations of these systems no choice of acceptable complex structure leads to a unitary evolution...
1001.0066
Xin Li
Xin Li, Zhe Chang and Minghua Li
A matter dominated navigation Universe in accordance with the Type Ia supernova data
null
null
null
null
gr-qc
http://creativecommons.org/licenses/by/3.0/
We investigate a matter dominated navigation cosmological model. The influence of a possible drift (wind) in the navigation cosmological model makes the spacetime geometry change from Riemannian to Finslerian. The evolution of the Finslerian Universe is governed by the same gravitational field equation with the famil...
[ { "created": "Thu, 31 Dec 2009 02:23:04 GMT", "version": "v1" }, { "created": "Wed, 7 Apr 2010 10:56:01 GMT", "version": "v2" } ]
2015-03-13
[ [ "Li", "Xin", "" ], [ "Chang", "Zhe", "" ], [ "Li", "Minghua", "" ] ]
We investigate a matter dominated navigation cosmological model. The influence of a possible drift (wind) in the navigation cosmological model makes the spacetime geometry change from Riemannian to Finslerian. The evolution of the Finslerian Universe is governed by the same gravitational field equation with the familia...
1803.02351
Simone Dresti
Laura Covi and Simone Dresti
Time-dependent Features in the Primordial Spectrum
31 pages, 13 figures. Typos, estimates and normalization of plots corrected. Conclusions mostly unchanged
null
null
null
gr-qc hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In a Quantum Field Theory with a time-dependent background, time-translational symmetry is broken. We therefore expect time-dependent loop corrections to cosmological observables after renormalization for an interacting field, with the consequent physical implications. In this paper we compute and discuss such radiat...
[ { "created": "Tue, 6 Mar 2018 14:08:01 GMT", "version": "v1" }, { "created": "Tue, 20 Mar 2018 13:39:47 GMT", "version": "v2" } ]
2018-03-21
[ [ "Covi", "Laura", "" ], [ "Dresti", "Simone", "" ] ]
In a Quantum Field Theory with a time-dependent background, time-translational symmetry is broken. We therefore expect time-dependent loop corrections to cosmological observables after renormalization for an interacting field, with the consequent physical implications. In this paper we compute and discuss such radiativ...
gr-qc/0406074
Alex Calogeracos
Alex Calogeracos
A detailed recalculation of the spectrum of radiation emitted during gravitational collapse of a spherically symmetric star
3 figures
null
null
null
gr-qc
null
We address the question of radiation emitted from a collapsing star. We consider the simple model of a spherical star consisting of pressure-free dust and we derive the emission spectrum via a systematic asymptotic expansion of the complete Bogolubov amplitude. We present a review of standard features of the problem ...
[ { "created": "Fri, 18 Jun 2004 16:39:43 GMT", "version": "v1" } ]
2007-05-23
[ [ "Calogeracos", "Alex", "" ] ]
We address the question of radiation emitted from a collapsing star. We consider the simple model of a spherical star consisting of pressure-free dust and we derive the emission spectrum via a systematic asymptotic expansion of the complete Bogolubov amplitude. We present a review of standard features of the problem an...
2002.04541
Yigit Yargic
Yigit Yargic, Marc Geiller
Modular polymer representations of the Weyl algebra
33 pages
null
null
null
gr-qc math-ph math.MP quant-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
One of the key conceptual challenges in quantum gravity is to understand how quantum theory should modify the very notion of spacetime. One way to investigate this question is to study the alternatives to Schr\"odinger quantum mechanics. The polymer representation, inspired by loop quantum gravity, can be understood ...
[ { "created": "Tue, 11 Feb 2020 16:49:34 GMT", "version": "v1" } ]
2020-02-12
[ [ "Yargic", "Yigit", "" ], [ "Geiller", "Marc", "" ] ]
One of the key conceptual challenges in quantum gravity is to understand how quantum theory should modify the very notion of spacetime. One way to investigate this question is to study the alternatives to Schr\"odinger quantum mechanics. The polymer representation, inspired by loop quantum gravity, can be understood as...
gr-qc/0012105
Alberto Saa
A. Saa, E. Gunzig, L. Brenig, V. Faraoni, T.M. Rocha Filho, and A. Figueiredo
Superinflation, quintessence, and the avoidance of the initial singularity
RevTex, 10 pages, 4 figures, To appear in the proceedings of the 5th Peyresq meeting
Int.J.Theor.Phys. 40 (2001) 2295
null
null
gr-qc
null
We consider the dynamics of a spatially flat universe dominated by a self-interacting nonminimally coupled scalar field. The structure of the phase space and complete phase portraits for the conformal coupling case are given. It is shown that the non-minimal coupling modifies drastically the dynamics of the universe....
[ { "created": "Thu, 28 Dec 2000 16:57:04 GMT", "version": "v1" } ]
2007-05-23
[ [ "Saa", "A.", "" ], [ "Gunzig", "E.", "" ], [ "Brenig", "L.", "" ], [ "Faraoni", "V.", "" ], [ "Filho", "T. M. Rocha", "" ], [ "Figueiredo", "A.", "" ] ]
We consider the dynamics of a spatially flat universe dominated by a self-interacting nonminimally coupled scalar field. The structure of the phase space and complete phase portraits for the conformal coupling case are given. It is shown that the non-minimal coupling modifies drastically the dynamics of the universe. N...
gr-qc/0307068
Hiroyuki Tashiro
Hiroyuki Tashiro, Takeshi Chiba, Misao Sasaki
Reheating After Quintessential Inflation and Gravitational Waves
15 pages, 5 figures, to be published in CQG
Class.Quant.Grav.21:1761-1772,2004
10.1088/0264-9381/21/7/004
null
gr-qc astro-ph
null
We investigate the dependence of the gravitational wave spectrum from quintessential inflation on the reheating process. We consider two extreme reheating processes. One is the gravitational reheating by particle creation in the expanding universe in which the beginning of the radiation dominated epoch is delayed due...
[ { "created": "Tue, 15 Jul 2003 14:03:57 GMT", "version": "v1" }, { "created": "Mon, 9 Feb 2004 05:26:56 GMT", "version": "v2" } ]
2009-10-09
[ [ "Tashiro", "Hiroyuki", "" ], [ "Chiba", "Takeshi", "" ], [ "Sasaki", "Misao", "" ] ]
We investigate the dependence of the gravitational wave spectrum from quintessential inflation on the reheating process. We consider two extreme reheating processes. One is the gravitational reheating by particle creation in the expanding universe in which the beginning of the radiation dominated epoch is delayed due t...
1912.12650
Samad Khakshournia
S. Khakshournia and R. Mansouri
On the stress-energy tensor of a null shell in Einstein-Cartan gravity
7 pages
Class. Quant. Grav. 36 (2019) 227001
10.1088/1361-6382/ab47d4
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The stress-energy tensor of a matter shell whose history coincides with a null hypersurface in the Einstein-Cartan gravity is revisited. It is demonstrated that with a proper choice for the torsion discontinuity taken to be orthogonal to the null hypersurface and consistent with the antisymmetric property of torsion ...
[ { "created": "Sun, 29 Dec 2019 13:44:14 GMT", "version": "v1" } ]
2020-01-08
[ [ "Khakshournia", "S.", "" ], [ "Mansouri", "R.", "" ] ]
The stress-energy tensor of a matter shell whose history coincides with a null hypersurface in the Einstein-Cartan gravity is revisited. It is demonstrated that with a proper choice for the torsion discontinuity taken to be orthogonal to the null hypersurface and consistent with the antisymmetric property of torsion te...
1604.06279
Chung-Ming Ko
Chung-Ming Ko
On the problem of deformed spherical systems in Modified Newtonian Dynamics
30 pages, 2 figures
Astrophysical Journal, 821, 111 (12pp), 2016 April 20
10.3847/0004-637X/821/2/111
null
gr-qc astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Based on Newtonian dynamics, observations show that the luminous masses of astrophysical objects that are the size of a galaxy or larger are not enough to generate the measured motions which they supposedly determine. This is typically attributed to the existence of dark matter, which possesses mass but does not radi...
[ { "created": "Wed, 20 Apr 2016 11:17:39 GMT", "version": "v1" } ]
2016-04-22
[ [ "Ko", "Chung-Ming", "" ] ]
Based on Newtonian dynamics, observations show that the luminous masses of astrophysical objects that are the size of a galaxy or larger are not enough to generate the measured motions which they supposedly determine. This is typically attributed to the existence of dark matter, which possesses mass but does not radiat...
1003.2049
Myungseok Eune
Ee Chang-Young, Myungseok Eune, Kyoungtae Kimm, Daeho Lee
Surface gravity and Hawking temperature from entropic force viewpoint
7 pages, 1 figure; RevTeX4
Mod.Phys.Lett. A 25 (2010) 2825-2830
10.1142/S0217732310033979
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider a freely falling holographic screen for the Schwarzschild and Reissner-Nordstr\"om black holes and evaluate the entropic force \`a la Verlinde. When the screen crosses the event horizon, the temperature of the screen agrees to the Hawking temperature and the entropic force gives rise to the surface gravit...
[ { "created": "Wed, 10 Mar 2010 08:54:37 GMT", "version": "v1" }, { "created": "Mon, 15 Mar 2010 05:04:36 GMT", "version": "v2" }, { "created": "Fri, 2 Apr 2010 05:37:08 GMT", "version": "v3" } ]
2010-11-03
[ [ "Chang-Young", "Ee", "" ], [ "Eune", "Myungseok", "" ], [ "Kimm", "Kyoungtae", "" ], [ "Lee", "Daeho", "" ] ]
We consider a freely falling holographic screen for the Schwarzschild and Reissner-Nordstr\"om black holes and evaluate the entropic force \`a la Verlinde. When the screen crosses the event horizon, the temperature of the screen agrees to the Hawking temperature and the entropic force gives rise to the surface gravity ...
1812.10960
Lau Loi So
Lau Loi So
The modification of the Bel-Robinson energy-momentum
9 pages, a major revision of arXiv:1405.7883
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
For describing the non-negative gravitational energy-momentum in terms of a pure Bel-Robinson `momentum' in a quasi-local small sphere limit, the Bel-Robinson tensor $B$ is desirable. However, we found this Bel-Robinson `momentum' can be modified such that it still satisfy the non-spacelike and future pointing requir...
[ { "created": "Fri, 28 Dec 2018 11:49:55 GMT", "version": "v1" } ]
2018-12-31
[ [ "So", "Lau Loi", "" ] ]
For describing the non-negative gravitational energy-momentum in terms of a pure Bel-Robinson `momentum' in a quasi-local small sphere limit, the Bel-Robinson tensor $B$ is desirable. However, we found this Bel-Robinson `momentum' can be modified such that it still satisfy the non-spacelike and future pointing requirem...
1401.2403
Abdul Jawad
M. Sharif and Abdul Jawad
Reconstruction of Scalar Field Dark Energy Models in Kaluza-Klein Universe
16 pages, 12 figures
Commun. Theor. Phys. 60(2013)183
10.1088/0253-6102/60/2/07
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper is devoted to study the modified holographic dark energy model by taking its different aspects in the flat Kaluza-Klein universe. We construct the equation of state parameter which evolutes the universe from quintessence region towards the vacuum. It is found that the modified holographic model exhibits in...
[ { "created": "Fri, 25 Oct 2013 10:04:25 GMT", "version": "v1" } ]
2015-06-18
[ [ "Sharif", "M.", "" ], [ "Jawad", "Abdul", "" ] ]
This paper is devoted to study the modified holographic dark energy model by taking its different aspects in the flat Kaluza-Klein universe. We construct the equation of state parameter which evolutes the universe from quintessence region towards the vacuum. It is found that the modified holographic model exhibits inst...
1610.06032
Ezequiel Boero
Ezequiel F. Boero, Osvaldo M. Moreschi
Gravitational lens optical scalars in terms of energy-momentum distributions in the cosmological framework
23 pages, 4 figures
Monthly Notices of the Royal Astronomical Society, Volume 475, Issu 4, 21 April 2018, Pages 4683-4703
10.1093/mnras/sty110
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present new results on gravitational lensing over a cosmological Robertson-Walker backgrounds which extend and generalize previous works. Our expressions show the presence of new terms and factors which have been neglected in the literature on the subject. The new equations derived here for the optcal scalars allo...
[ { "created": "Wed, 19 Oct 2016 14:32:14 GMT", "version": "v1" }, { "created": "Sat, 31 Dec 2016 19:29:07 GMT", "version": "v2" }, { "created": "Fri, 24 Mar 2017 20:57:35 GMT", "version": "v3" }, { "created": "Thu, 28 Sep 2017 13:10:26 GMT", "version": "v4" }, { "c...
2018-05-23
[ [ "Boero", "Ezequiel F.", "" ], [ "Moreschi", "Osvaldo M.", "" ] ]
We present new results on gravitational lensing over a cosmological Robertson-Walker backgrounds which extend and generalize previous works. Our expressions show the presence of new terms and factors which have been neglected in the literature on the subject. The new equations derived here for the optcal scalars allow ...
gr-qc/0308080
Suresh Paingalil Kunjan
P.K.Suresh
Particle Creation in Anisotropically Expanding Universe
9 pages,LATEX, no figures
Int.J.Theor.Phys. 44 (2005) 645-654
null
null
gr-qc
null
Using squeezed vacuum state formalism of quantum optics, an approximate solution to the semiclassical Einstein equation is obtained in Bianchi type-I universe. The phenomena of nonclassical particle creation is also examined in the anisotropic background cosmology.
[ { "created": "Mon, 25 Aug 2003 05:57:12 GMT", "version": "v1" } ]
2007-05-23
[ [ "Suresh", "P. K.", "" ] ]
Using squeezed vacuum state formalism of quantum optics, an approximate solution to the semiclassical Einstein equation is obtained in Bianchi type-I universe. The phenomena of nonclassical particle creation is also examined in the anisotropic background cosmology.
1311.6348
Artur Alho
Artur Alho, Filipe C. Mena
Covariant and gauge-invariant linear scalar perturbations in multiple scalar field cosmologies
42 pages, 32 figures
Phys. Rev. D 90, 043501 (2014)
10.1103/PhysRevD.90.043501
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We derive a set of equations monitoring the evolution of covariant and gauge-invariant linear scalar perturbations of Friedman-Lema\^itre-Robertson-Walker models with multiple interacting non-linear scalar fields. We use a dynamical systems' approach in order to perform a stability analysis for some classes of scalar...
[ { "created": "Mon, 25 Nov 2013 16:06:51 GMT", "version": "v1" } ]
2014-08-06
[ [ "Alho", "Artur", "" ], [ "Mena", "Filipe C.", "" ] ]
We derive a set of equations monitoring the evolution of covariant and gauge-invariant linear scalar perturbations of Friedman-Lema\^itre-Robertson-Walker models with multiple interacting non-linear scalar fields. We use a dynamical systems' approach in order to perform a stability analysis for some classes of scalar f...
1001.0923
Soumya Mohanty
Yan Wang, Soumya D. Mohanty
Particle Swarm Optimization and gravitational wave data analysis: Performance on a binary inspiral testbed
13 pages, 5 figures
Phys.Rev.D81:063002,2010
10.1103/PhysRevD.81.063002
null
gr-qc physics.data-an
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The detection and estimation of gravitational wave (GW) signals belonging to a parameterized family of waveforms requires, in general, the numerical maximization of a data-dependent function of the signal parameters. Due to noise in the data, the function to be maximized is often highly multi-modal with numerous loca...
[ { "created": "Wed, 6 Jan 2010 15:51:18 GMT", "version": "v1" } ]
2010-04-21
[ [ "Wang", "Yan", "" ], [ "Mohanty", "Soumya D.", "" ] ]
The detection and estimation of gravitational wave (GW) signals belonging to a parameterized family of waveforms requires, in general, the numerical maximization of a data-dependent function of the signal parameters. Due to noise in the data, the function to be maximized is often highly multi-modal with numerous local ...
1201.4250
Alicja Siwek
M. Gawe{\l}czyk, J. Polonyi, A. Radosz, A. Siwek
Exchange of signals around the event horizon in Schwarzschild space-time
7 pages, 6 figures
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Red shift in communication and possibility of interaction is discussed for objects around the event horizon of Schwarzschild space-time. It is pointed out that the arrow of time within the horizon cannot always be inferred by observations carried out outside. Two scenarios are presented for the causal structure of th...
[ { "created": "Fri, 20 Jan 2012 10:26:28 GMT", "version": "v1" } ]
2012-01-23
[ [ "Gawełczyk", "M.", "" ], [ "Polonyi", "J.", "" ], [ "Radosz", "A.", "" ], [ "Siwek", "A.", "" ] ]
Red shift in communication and possibility of interaction is discussed for objects around the event horizon of Schwarzschild space-time. It is pointed out that the arrow of time within the horizon cannot always be inferred by observations carried out outside. Two scenarios are presented for the causal structure of the ...
2002.01473
Antonios Tsokaros A.
Antonios Tsokaros, Milton Ruiz, Stuart L. Shapiro
Locating ergostar models in parameter space
8 pages, 3 figures. Matches published version
Phys. Rev. D 101, 064069 (2020)
10.1103/PhysRevD.101.064069
null
gr-qc astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Recently, we have shown that dynamically stable ergostar solutions (equilibrium neutron stars that contain an ergoregion) with a compressible and causal equation of state exist [A. Tsokaros, M. Ruiz, L. Sun, S. L. Shapiro, and K. Ury\=u, Phys. Rev. Lett. 123, 231103 (2019)]. These stars are hypermassive, differential...
[ { "created": "Tue, 4 Feb 2020 18:59:58 GMT", "version": "v1" }, { "created": "Mon, 30 Mar 2020 16:58:10 GMT", "version": "v2" } ]
2020-04-08
[ [ "Tsokaros", "Antonios", "" ], [ "Ruiz", "Milton", "" ], [ "Shapiro", "Stuart L.", "" ] ]
Recently, we have shown that dynamically stable ergostar solutions (equilibrium neutron stars that contain an ergoregion) with a compressible and causal equation of state exist [A. Tsokaros, M. Ruiz, L. Sun, S. L. Shapiro, and K. Ury\=u, Phys. Rev. Lett. 123, 231103 (2019)]. These stars are hypermassive, differentially...
0712.0427
Matt Visser
Matt Visser (Victoria University of Wellington) and Silke Weinfurtner (Victoria University of Wellington)
Analogue spacetimes: Toy models for "quantum gravity''
24 pages; Based on a talk at the conference: From Quantum to Emergent Gravity: Theory and Phenomenology, June 11-15 2007, Trieste, Italy
PoSQG-Ph:042,2007
null
null
gr-qc
null
Why are "analogue spacetimes'' interesting? For the purposes of this workshop the answer is simple: Analogue spacetimes provide one with physically well-defined and physically well-understood concrete models of many of the phenomena that seem to be part of the yet incomplete theory of "quantum gravity'', or more acce...
[ { "created": "Tue, 4 Dec 2007 03:35:09 GMT", "version": "v1" } ]
2009-04-14
[ [ "Visser", "Matt", "", "Victoria University of Wellington" ], [ "Weinfurtner", "Silke", "", "Victoria University of Wellington" ] ]
Why are "analogue spacetimes'' interesting? For the purposes of this workshop the answer is simple: Analogue spacetimes provide one with physically well-defined and physically well-understood concrete models of many of the phenomena that seem to be part of the yet incomplete theory of "quantum gravity'', or more access...
gr-qc/9801039
Toporenskij A. V.
A.Yu.Kamenshchik (Landau Institute for theoretical physics, Moscow, Russia), I.M.Khalatnikov (Landau Institute for theoretical physics and Tel Avive University, Ramat Avive, Israel) and A.V.Toporensky (Sternberg Astronomical Institute, Moscow, Russia)
Complex inflaton field in quantum cosmology
34 pages with 2 gif figures, mprocl.sty, To appear in International Journal of Modern Physics D
Int.J.Mod.Phys.D6:649-672,1997
10.1142/S0218271897000406
null
gr-qc
null
We investigate the cosmological model with the complex scalar self-interacting inflaton field non-minimally coupled to gravity. The different geometries of the Euclidean classically forbidden regions are represented. The instanton solutions of the corresponding Euclidean equations of motion are found by numerical cal...
[ { "created": "Mon, 12 Jan 1998 20:13:07 GMT", "version": "v1" } ]
2014-11-17
[ [ "Kamenshchik", "A. Yu.", "", "Landau Institute for theoretical physics, Moscow,\n Russia" ], [ "Khalatnikov", "I. M.", "", "Landau Institute for theoretical physics and Tel\n Avive University, Ramat Avive, Israel" ], [ "Toporensky", "A. V.", "", "Sternberg...
We investigate the cosmological model with the complex scalar self-interacting inflaton field non-minimally coupled to gravity. The different geometries of the Euclidean classically forbidden regions are represented. The instanton solutions of the corresponding Euclidean equations of motion are found by numerical calcu...
0806.4952
Idan Shilon
Eduardo I. Guendelman and Idan Shilon
Stabilization of Neutral Thin Shells By Gravitational Effects From Electric Fields
5 pages, 1 figure
Class.Quant.Grav.26:045007,2009
10.1088/0264-9381/26/4/045007
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the properties of a system consisting of an uncharged spherically symmetric two dimensional extended object which encloses a stationary point charge placed in the shell's center. We show that there can be a static and stable configuration for the neutral shell, using only the gravitational field of the charg...
[ { "created": "Mon, 30 Jun 2008 17:14:32 GMT", "version": "v1" }, { "created": "Mon, 22 Sep 2008 16:30:53 GMT", "version": "v2" }, { "created": "Fri, 6 Feb 2009 17:34:24 GMT", "version": "v3" } ]
2009-02-09
[ [ "Guendelman", "Eduardo I.", "" ], [ "Shilon", "Idan", "" ] ]
We study the properties of a system consisting of an uncharged spherically symmetric two dimensional extended object which encloses a stationary point charge placed in the shell's center. We show that there can be a static and stable configuration for the neutral shell, using only the gravitational field of the charged...
gr-qc/0603117
Vjacheslav Dorofeev
V.Dorofeev
A self-consistent solution in affine space with scalar field
4 pages, LaTeX
Izvestija VUZov (Russia), Fizika, N4, p22 (2000)
null
null
gr-qc
null
Conformal connection of scalar field is shown to produce possible non-metricity in affine connection spaces. In case of self-consistent solution the non-metricity is a correction to background Riemannian structure with respect to gravitational constant and its magnitude may be essential in the early Universe.
[ { "created": "Wed, 29 Mar 2006 13:21:27 GMT", "version": "v1" } ]
2010-10-12
[ [ "Dorofeev", "V.", "" ] ]
Conformal connection of scalar field is shown to produce possible non-metricity in affine connection spaces. In case of self-consistent solution the non-metricity is a correction to background Riemannian structure with respect to gravitational constant and its magnitude may be essential in the early Universe.
1007.5227
Remo Garattini
Remo Garattini
Gravitational Zero Point Energy and the Induced Cosmological Constant
LaTeX 10 Pages. Submitted to the volume "Cosmology, Quantum Vacuum, and Zeta Functions", in honour of Professor Emilio Elizalde on the occasion of his 60th birthday
null
10.1007/978-3-642-19760-4_17
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss how to extract information about the cosmological constant from the Wheeler-DeWitt equation, considered as an eigenvalue of a Sturm-Liouville problem in a generic spherically symmetric background. The equation is approximated to one loop with the help of a variational approach with Gaussian trial wave func...
[ { "created": "Thu, 29 Jul 2010 14:25:38 GMT", "version": "v1" } ]
2015-05-19
[ [ "Garattini", "Remo", "" ] ]
We discuss how to extract information about the cosmological constant from the Wheeler-DeWitt equation, considered as an eigenvalue of a Sturm-Liouville problem in a generic spherically symmetric background. The equation is approximated to one loop with the help of a variational approach with Gaussian trial wave functi...
0902.2001
Steffen Gielen
Gary W. Gibbons, Steffen Gielen
Deformed General Relativity and Torsion
20 pages, 1 figure, revtex; expanded sections 3 and 4 for clarity, moved material to appendix B, corrected a few minor errors
Class.Quant.Grav.26:135005,2009
10.1088/0264-9381/26/13/135005
DAMTP-2009-9
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We argue that the natural framework for embedding the ideas of deformed, or doubly, special relativity (DSR) into a curved spacetime is a generalisation of Einstein-Cartan theory, considered by Stelle and West. Instead of interpreting the noncommuting "spacetime coordinates" of the Snyder algebra as endowing spacetim...
[ { "created": "Wed, 11 Feb 2009 21:47:50 GMT", "version": "v1" }, { "created": "Mon, 23 Feb 2009 16:40:14 GMT", "version": "v2" }, { "created": "Fri, 3 Apr 2009 22:12:37 GMT", "version": "v3" } ]
2009-06-19
[ [ "Gibbons", "Gary W.", "" ], [ "Gielen", "Steffen", "" ] ]
We argue that the natural framework for embedding the ideas of deformed, or doubly, special relativity (DSR) into a curved spacetime is a generalisation of Einstein-Cartan theory, considered by Stelle and West. Instead of interpreting the noncommuting "spacetime coordinates" of the Snyder algebra as endowing spacetime ...
1201.2871
Christof Wetterich
C.Wetterich
Spinor gravity and diffeomorphism invariance on the lattice
13 pages, proceedings 6th Aegean Summer School, Naxos 2011
null
10.1007/978-3-642-33036-0_4
null
gr-qc hep-lat hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The key ingredient for lattice regularized quantum gravity is diffeomorphism symmetry. We formulate a lattice functional integral for quantum gravity in terms of fermions. This allows for a diffeomorphism invariant functional measure and avoids problems of boundedness of the action. We discuss the concept of lattice ...
[ { "created": "Fri, 13 Jan 2012 15:43:44 GMT", "version": "v1" } ]
2015-06-03
[ [ "Wetterich", "C.", "" ] ]
The key ingredient for lattice regularized quantum gravity is diffeomorphism symmetry. We formulate a lattice functional integral for quantum gravity in terms of fermions. This allows for a diffeomorphism invariant functional measure and avoids problems of boundedness of the action. We discuss the concept of lattice di...
1601.06152
Barun Majumder
Narayan Banerjee and Barun Majumder
A question mark on the equivalence of Einstein and Jordan frames
6 pages, 4 figures. Online in Phys Lett B
null
10.1016/j.physletb.2016.01.022
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
With an explicit example, we show that Jordan frame and the conformally transformed Einstein frames clearly lead to different physics for a non-minimally coupled theory of gravity, namely Brans-Dicke theory, at least at the quantum level. The example taken up is the spatially flat Friedmann cosmology in Brans-Dicke t...
[ { "created": "Thu, 21 Jan 2016 18:42:12 GMT", "version": "v1" } ]
2016-01-25
[ [ "Banerjee", "Narayan", "" ], [ "Majumder", "Barun", "" ] ]
With an explicit example, we show that Jordan frame and the conformally transformed Einstein frames clearly lead to different physics for a non-minimally coupled theory of gravity, namely Brans-Dicke theory, at least at the quantum level. The example taken up is the spatially flat Friedmann cosmology in Brans-Dicke the...
2012.02587
M. Ilyas
M. Ilyas
Compact Stars in $f(\mathcal{R,G,T})$ Gravity
Some changes have been made. " To appear in International Journal of Modern Physics A"
Int. J. Mod. Phys. A 36, 2150165 (2021)
10.1142/S0217751X21501657
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The present work is to introduce a new kind of modified gravitational theory, named as $f(\mathcal{R,G,T})$ (also $f(\mathcal{R,T,G})$) gravity, where $\mathcal{R}$ is the Ricci scalar, $\mathcal{G}$ is Gauss-Bonnet invariant and $\mathcal{T}$ is the trace of the energy-momentum tensor. With the help of different mod...
[ { "created": "Wed, 2 Dec 2020 06:57:53 GMT", "version": "v1" }, { "created": "Tue, 31 Aug 2021 13:21:17 GMT", "version": "v2" } ]
2021-11-16
[ [ "Ilyas", "M.", "" ] ]
The present work is to introduce a new kind of modified gravitational theory, named as $f(\mathcal{R,G,T})$ (also $f(\mathcal{R,T,G})$) gravity, where $\mathcal{R}$ is the Ricci scalar, $\mathcal{G}$ is Gauss-Bonnet invariant and $\mathcal{T}$ is the trace of the energy-momentum tensor. With the help of different model...
gr-qc/0604038
Prasanta Mahato
Prasanta Mahato
$\theta$-Term and Cosmological Constant from CJD Action
5 pages
Mod.Phys.Lett. A17 (2002) 475-479
10.1142/S0217732302006710
null
gr-qc
null
In the gravity without metric formalism of Capovilla, Jacobson and Dell, the topological $\theta$-term appears through a canonical transformation.The origin of this canonical transformation is probed here. It is shown here that when $\theta$-term appears cosmological $\lambda$-term also appears simultaneously.
[ { "created": "Sun, 9 Apr 2006 16:56:33 GMT", "version": "v1" }, { "created": "Tue, 11 Apr 2006 05:04:52 GMT", "version": "v2" } ]
2009-11-11
[ [ "Mahato", "Prasanta", "" ] ]
In the gravity without metric formalism of Capovilla, Jacobson and Dell, the topological $\theta$-term appears through a canonical transformation.The origin of this canonical transformation is probed here. It is shown here that when $\theta$-term appears cosmological $\lambda$-term also appears simultaneously.
2111.02129
Gabriele Barca
Gabriele Barca, Eleonora Giovannetti, Federico Mandini, Giovanni Montani
Polymer Quantization of the Isotropic Universe: comparison with the Bounce of Loop Quantum Cosmology
To appear in the Proceedings of the 16th Marcel Grossmann meeting (5-10 July, 2021)
null
10.1142/9789811269776_0217
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We implement Polymer Quantum Mechanics on the Hamiltonian formulation of the isotropic Universe in both the representations of the standard Ashtekar-Barbero-Immirzi connection and of a new generalized coordinate conjugate to the Universe volume. The resulting dynamics is a bouncing cosmology; when quantizing the volu...
[ { "created": "Wed, 3 Nov 2021 10:53:39 GMT", "version": "v1" } ]
2023-02-01
[ [ "Barca", "Gabriele", "" ], [ "Giovannetti", "Eleonora", "" ], [ "Mandini", "Federico", "" ], [ "Montani", "Giovanni", "" ] ]
We implement Polymer Quantum Mechanics on the Hamiltonian formulation of the isotropic Universe in both the representations of the standard Ashtekar-Barbero-Immirzi connection and of a new generalized coordinate conjugate to the Universe volume. The resulting dynamics is a bouncing cosmology; when quantizing the volume...
gr-qc/9705053
Guy Burdet
G.Burdet and M.Perrin
Quantum Gravity:the axiomatic approach, a possible interpretation
plain-TeX,9 pages
null
null
null
gr-qc
null
Twenty years ago, by extending the Wightman axiom framework, it has been found possible to quantize only a conformal factor of the gravitational field. Gravitons being excluded from this quantum scalar field theory, numerous attempts were done to give a valuable description of what could be quantum gravity. In this t...
[ { "created": "Wed, 21 May 1997 07:52:43 GMT", "version": "v1" } ]
2007-05-23
[ [ "Burdet", "G.", "" ], [ "Perrin", "M.", "" ] ]
Twenty years ago, by extending the Wightman axiom framework, it has been found possible to quantize only a conformal factor of the gravitational field. Gravitons being excluded from this quantum scalar field theory, numerous attempts were done to give a valuable description of what could be quantum gravity. In this tal...
1104.1150
Yuri Bonder
Yuri Bonder
Lorentz invariant phenomenology of quantum gravity: Main ideas behind the model
This work was presented at Rencontres de Moriond and GPhyS Colloquium: Gravitational Waves and Experimental Gravity 2011; 3 pages
null
null
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In the past decade the phenomenology of quantum gravity has been dominated by the search of violations of Lorentz invariance. However, there are very serious arguments that led us to assume that this invariance is a symmetry in Nature. This motivated us to construct a phenomenological model describing how a Lorentz i...
[ { "created": "Wed, 6 Apr 2011 17:06:02 GMT", "version": "v1" } ]
2011-04-07
[ [ "Bonder", "Yuri", "" ] ]
In the past decade the phenomenology of quantum gravity has been dominated by the search of violations of Lorentz invariance. However, there are very serious arguments that led us to assume that this invariance is a symmetry in Nature. This motivated us to construct a phenomenological model describing how a Lorentz inv...
0908.0365
Frank B. Estabrook
Frank B. Estabrook
The Hilbert Lagrangian and Isometric Embedding: Tetrad Formulation of Regge-Teitelboim Gravity
12 pages, 1 figure. Version 2 has modified title and text, reflecting added earlier references. New Introduction
J. Math. Phys. 51:042502,2010
10.1063/1.3352557
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss Exterior Differential Systems (EDS) for the vacuum gravitational field. These EDS are derived by varying the Hilbert-Einstein Lagrangian, given most elegantly as a Cartan 4-forrm calibrating 4-spaces embedded in ten flat dimensions. In particular we thus formulate with tetrad equations the Regge-Teitelboim...
[ { "created": "Mon, 3 Aug 2009 23:59:45 GMT", "version": "v1" }, { "created": "Fri, 16 Oct 2009 18:34:26 GMT", "version": "v2" } ]
2010-05-12
[ [ "Estabrook", "Frank B.", "" ] ]
We discuss Exterior Differential Systems (EDS) for the vacuum gravitational field. These EDS are derived by varying the Hilbert-Einstein Lagrangian, given most elegantly as a Cartan 4-forrm calibrating 4-spaces embedded in ten flat dimensions. In particular we thus formulate with tetrad equations the Regge-Teitelboim d...
gr-qc/0210102
Nils Andersson
K.H. Lockitch, J.L. Friedman and N. Andersson
The rotational modes of relativistic stars: Numerical results
RevTeX, 29 pages, 31 eps figures
Phys.Rev. D68 (2003) 124010
10.1103/PhysRevD.68.124010
null
gr-qc astro-ph
null
We study the inertial modes of slowly rotating, fully relativistic compact stars. The equations that govern perturbations of both barotropic and non-barotropic models are discussed, but we present numerical results only for the barotropic case. For barotropic stars all inertial modes are a hybrid mixture of axial and...
[ { "created": "Tue, 29 Oct 2002 18:12:15 GMT", "version": "v1" } ]
2009-11-07
[ [ "Lockitch", "K. H.", "" ], [ "Friedman", "J. L.", "" ], [ "Andersson", "N.", "" ] ]
We study the inertial modes of slowly rotating, fully relativistic compact stars. The equations that govern perturbations of both barotropic and non-barotropic models are discussed, but we present numerical results only for the barotropic case. For barotropic stars all inertial modes are a hybrid mixture of axial and p...
2302.01159
Andrew Mummery
Andrew Mummery and Steven Balbus
A complete characterisation of the orbital shapes of the non-circular Kerr geodesic solutions with circular orbit constants of motion
14 pages, 10 figures. Comments welcomed
null
10.1103/PhysRevD.107.124058
null
gr-qc
http://creativecommons.org/licenses/by/4.0/
We present analytical solutions describing a family of both inwardly and outwardly spiralling orbits in the Kerr spacetime. The solutions are exact, and remarkable for their simplicity. These orbits all have the angular momentum and energy of a circular orbit at some radius $r_c$, but are not restricted to remaining ...
[ { "created": "Thu, 2 Feb 2023 15:26:30 GMT", "version": "v1" } ]
2023-07-12
[ [ "Mummery", "Andrew", "" ], [ "Balbus", "Steven", "" ] ]
We present analytical solutions describing a family of both inwardly and outwardly spiralling orbits in the Kerr spacetime. The solutions are exact, and remarkable for their simplicity. These orbits all have the angular momentum and energy of a circular orbit at some radius $r_c$, but are not restricted to remaining on...
2405.05410
Avi Loeb
Abraham Loeb (Harvard)
Pulsar Timing Noise from Brownian Motion of the Sun
Accepted for publication in ApJL, 5 pages (final version)
null
null
null
gr-qc astro-ph.EP astro-ph.SR
http://creativecommons.org/licenses/by/4.0/
Recently, Pulsar Timing Arrays (PTAs) reported a signal at nanohertz frequencies consistent with a stochastic gravitational wave background. Here, I show that the Brownian motion of the Sun as a result of its random gravitational interactions with the cluster of thousands of unmodeled Main-belt asteroids of diameters...
[ { "created": "Wed, 8 May 2024 20:25:04 GMT", "version": "v1" }, { "created": "Mon, 13 May 2024 17:54:13 GMT", "version": "v2" }, { "created": "Wed, 15 May 2024 15:30:31 GMT", "version": "v3" }, { "created": "Sat, 25 May 2024 09:00:53 GMT", "version": "v4" }, { "cr...
2024-06-13
[ [ "Loeb", "Abraham", "", "Harvard" ] ]
Recently, Pulsar Timing Arrays (PTAs) reported a signal at nanohertz frequencies consistent with a stochastic gravitational wave background. Here, I show that the Brownian motion of the Sun as a result of its random gravitational interactions with the cluster of thousands of unmodeled Main-belt asteroids of diameters <...
gr-qc/0208062
Alexander Westphal
A. Westphal
Quantum Mechanics and Gravitation
149 pages, 45 figures
null
null
null
gr-qc
null
In summer 1999 an experiment at ILL, Grenoble was conducted. So-called ultra-cold neutrons (UCN) were trapped in the vertical direction between the Fermi-potential of a smooth mirror below and the gravitational potential of the earth above [Ne00, Ru00]. If quantum mechanics turns out to be a sufficiently correct desc...
[ { "created": "Wed, 21 Aug 2002 20:38:21 GMT", "version": "v1" }, { "created": "Tue, 8 Apr 2003 19:43:08 GMT", "version": "v2" } ]
2007-05-23
[ [ "Westphal", "A.", "" ] ]
In summer 1999 an experiment at ILL, Grenoble was conducted. So-called ultra-cold neutrons (UCN) were trapped in the vertical direction between the Fermi-potential of a smooth mirror below and the gravitational potential of the earth above [Ne00, Ru00]. If quantum mechanics turns out to be a sufficiently correct descri...
0710.3690
Mark Israelit
Mark Israelit (Univ. Haifa - Oranim)
Wesson's IMT with a Weylian bulk
29 pages
Found.Phys.35:1725-1748,2005
10.1007/s10701-005-6518-5
null
gr-qc
null
The foundations of Wesson's induced matter theory are analyzed. It is shown that the 5D empty bulk must be regarded rather as a Weylian space than as a Riemannian one.The framework of a Weyl-Dirac version of Wesson's theory is elaborated and discussed. The bulk possesses in addition to the metric tensor a Weylian con...
[ { "created": "Fri, 19 Oct 2007 12:49:12 GMT", "version": "v1" } ]
2009-11-13
[ [ "Israelit", "Mark", "", "Univ. Haifa - Oranim" ] ]
The foundations of Wesson's induced matter theory are analyzed. It is shown that the 5D empty bulk must be regarded rather as a Weylian space than as a Riemannian one.The framework of a Weyl-Dirac version of Wesson's theory is elaborated and discussed. The bulk possesses in addition to the metric tensor a Weylian conne...
1001.0359
Parthasarathi Majumdar
Parthapratim Pradhan and Parthasarathi Majumdar
Circular Orbits in Extremal Reissner Nordstrom Spacetimes
13 Pages Latex 2e, no figures; title of paper, abstract and contents modified substantively following critique of anonymous referee
Phys.Lett.A375:474-479,2011
10.1016/j.physleta.2010.11.015
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Circular null geodesic orbits, in extremal Reissner-Nordstrom spacetimes, are examined with regard to their stability, and compared with similar orbits in the near-extremal situation. Extremization of the effective potential for null circular orbits shows the existence of a stable circular geodesic in the extremal sp...
[ { "created": "Sun, 3 Jan 2010 11:08:01 GMT", "version": "v1" }, { "created": "Thu, 1 Apr 2010 10:05:01 GMT", "version": "v2" } ]
2011-01-17
[ [ "Pradhan", "Parthapratim", "" ], [ "Majumdar", "Parthasarathi", "" ] ]
Circular null geodesic orbits, in extremal Reissner-Nordstrom spacetimes, are examined with regard to their stability, and compared with similar orbits in the near-extremal situation. Extremization of the effective potential for null circular orbits shows the existence of a stable circular geodesic in the extremal spac...
1106.3743
Jose Luis Jaramillo
Jos\'e Luis Jaramillo, Mart\'in Reiris and Sergio Dain
Black hole Area-Angular momentum inequality in non-vacuum spacetimes
5 pages, no figures, updated to match published version
Phys.Rev. D84, 121503(R) (2011)
10.1103/PhysRevD.84.121503
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show that the area-angular momentum inequality A\geq 8\pi|J| holds for axially symmetric closed outermost stably marginally trapped surfaces. These are horizon sections (in particular, apparent horizons) contained in otherwise generic non-necessarily axisymmetric black hole spacetimes, with non-negative cosmologic...
[ { "created": "Sun, 19 Jun 2011 13:22:02 GMT", "version": "v1" }, { "created": "Tue, 10 Jan 2012 14:06:01 GMT", "version": "v2" } ]
2012-08-28
[ [ "Jaramillo", "José Luis", "" ], [ "Reiris", "Martín", "" ], [ "Dain", "Sergio", "" ] ]
We show that the area-angular momentum inequality A\geq 8\pi|J| holds for axially symmetric closed outermost stably marginally trapped surfaces. These are horizon sections (in particular, apparent horizons) contained in otherwise generic non-necessarily axisymmetric black hole spacetimes, with non-negative cosmological...
1204.1530
Ayan Chatterjee
Ayan Chatterjee, Bhramar Chatterjee and Amit Ghosh
Hawking radiation from dynamical horizons
5 Pages
null
10.1103/PhysRevD.87.084051
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In completely local settings, we establish that a dynamically evolving black hole horizon can be assigned a Hawking temperature. Moreover, we calculate the Hawking flux and show that the radius of the horizon shrinks.
[ { "created": "Fri, 6 Apr 2012 18:39:47 GMT", "version": "v1" } ]
2015-06-04
[ [ "Chatterjee", "Ayan", "" ], [ "Chatterjee", "Bhramar", "" ], [ "Ghosh", "Amit", "" ] ]
In completely local settings, we establish that a dynamically evolving black hole horizon can be assigned a Hawking temperature. Moreover, we calculate the Hawking flux and show that the radius of the horizon shrinks.
1706.06812
Heon-Ju Lee
DongBong Yang and Heon-Ju Lee
Results in the Spontaneous Annihilation of the Cosmological Constant
6 pages
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We suggest a new formula, which allows the Schwarzschild's solution and the Einstein radius to be applied to the dynamic universe, when our universe is hypothetically regarded as a single dynamic black hole. In this study, a cosmological constant problem is solved in the simplest manner, while we find excellent agree...
[ { "created": "Wed, 21 Jun 2017 10:02:52 GMT", "version": "v1" } ]
2017-06-22
[ [ "Yang", "DongBong", "" ], [ "Lee", "Heon-Ju", "" ] ]
We suggest a new formula, which allows the Schwarzschild's solution and the Einstein radius to be applied to the dynamic universe, when our universe is hypothetically regarded as a single dynamic black hole. In this study, a cosmological constant problem is solved in the simplest manner, while we find excellent agreeme...
1703.10154
Bogeun Gwak
Bogeun Gwak
Collision of Two Rotating Hayward Black Holes
25 pages, 43 figures, published version in EPJC
Eur. Phys. J. C 77, no. 7, 482 (2017)
10.1140/epjc/s10052-017-5055-7
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate the spin interaction and the gravitational radiation thermally allowed in a head-on collision of two rotating Hayward black holes. The Hayward black hole is a regular black hole in a modified Einstein equation, and hence it can be an appropriate model to describe the extent to which the regularity effe...
[ { "created": "Wed, 29 Mar 2017 17:49:46 GMT", "version": "v1" }, { "created": "Fri, 21 Jul 2017 16:49:20 GMT", "version": "v2" } ]
2017-07-24
[ [ "Gwak", "Bogeun", "" ] ]
We investigate the spin interaction and the gravitational radiation thermally allowed in a head-on collision of two rotating Hayward black holes. The Hayward black hole is a regular black hole in a modified Einstein equation, and hence it can be an appropriate model to describe the extent to which the regularity effect...
1105.4515
Alexander Kamenshchik
A.A. Andrianov, F. Cannata and A.Yu. Kamenshchik
General solution of scalar field cosmology with a (piecewise) exponential potential
19 pages, 3 figures
null
10.1088/1475-7516/2011/10/004
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study in detail the general solution for a scalar field cosmology with an exponential potential, correcting some imprecisions, encountered previously in the literature. In addition, we generalize this solution for a piecewise exponential potential, which is continuous, but not smooth (with cusps).
[ { "created": "Mon, 23 May 2011 14:40:42 GMT", "version": "v1" } ]
2015-05-28
[ [ "Andrianov", "A. A.", "" ], [ "Cannata", "F.", "" ], [ "Kamenshchik", "A. Yu.", "" ] ]
We study in detail the general solution for a scalar field cosmology with an exponential potential, correcting some imprecisions, encountered previously in the literature. In addition, we generalize this solution for a piecewise exponential potential, which is continuous, but not smooth (with cusps).
0908.3665
Patrick Sutton
Patrick J. Sutton, Gareth Jones, Shourov Chatterji, Peter Michael Kalmus, Isabel Leonor, Stephen Poprocki, Jameson Rollins, Antony Searle, Leo Stein, Massimo Tinto, Michal Was
X-Pipeline: An analysis package for autonomous gravitational-wave burst searches
18 pages, 10 figures. Minor edits and clarifications; added more background on gravitational waves and detectors. To appear in New Journal of Physics.
New J.Phys.12:053034,2010
10.1088/1367-2630/12/5/053034
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Autonomous gravitational-wave searches -- fully automated analyses of data that run without human intervention or assistance -- are desirable for a number of reasons. They are necessary for the rapid identification of gravitational-wave burst candidates, which in turn will allow for follow-up observations by other ob...
[ { "created": "Tue, 25 Aug 2009 19:29:12 GMT", "version": "v1" }, { "created": "Wed, 7 Apr 2010 10:07:09 GMT", "version": "v2" } ]
2015-03-13
[ [ "Sutton", "Patrick J.", "" ], [ "Jones", "Gareth", "" ], [ "Chatterji", "Shourov", "" ], [ "Kalmus", "Peter Michael", "" ], [ "Leonor", "Isabel", "" ], [ "Poprocki", "Stephen", "" ], [ "Rollins", "Jameson", ...
Autonomous gravitational-wave searches -- fully automated analyses of data that run without human intervention or assistance -- are desirable for a number of reasons. They are necessary for the rapid identification of gravitational-wave burst candidates, which in turn will allow for follow-up observations by other obse...
2211.07497
Roberto Chan
R. Chan, M. F. A. da Silva and V. H. Satheeshkumar
Is Birkhoff's Theorem Valid in Einstein-Aether Theory?
19 pages, no figures
Physics Letters B, Volume 850, 2024, 138544
10.1016/j.physletb.2024.138544
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We attempt to answer whether Birkhoff's theorem (BT) is valid in the Einstein-Aether (EA) theory. The BT states that any spherically symmetric solution of the vacuum field equations must be static, unique, and asymptotically flat. For a general spherically symmetric metric with metric functions $A(r,t)$ \& $B(r,t)$, ...
[ { "created": "Mon, 14 Nov 2022 16:26:52 GMT", "version": "v1" }, { "created": "Thu, 27 Jul 2023 07:54:57 GMT", "version": "v2" } ]
2024-03-06
[ [ "Chan", "R.", "" ], [ "da Silva", "M. F. A.", "" ], [ "Satheeshkumar", "V. H.", "" ] ]
We attempt to answer whether Birkhoff's theorem (BT) is valid in the Einstein-Aether (EA) theory. The BT states that any spherically symmetric solution of the vacuum field equations must be static, unique, and asymptotically flat. For a general spherically symmetric metric with metric functions $A(r,t)$ \& $B(r,t)$, an...
1506.06948
Jose Geraldo Pereira
A. Araujo and J. G. Pereira
Entropy in locally-de Sitter spacetimes
11 pages. V2: presentation changes aiming at clarifying the text. Version accepted for publication in Int. J. Mod. Phys. D
Int. J. Mod. Phys. D 24 (2015) 1550099 (12 pages)
10.1142/S0218271815500996
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
As quotient spaces, Minkowski and de Sitter are fundamental spacetimes in the sense that they are known "a priori", independently of Einstein equation. They represent different non-gravitational backgrounds for the construction of physical theories. If general relativity is constructed on a de Sitter spacetime, the u...
[ { "created": "Tue, 23 Jun 2015 11:24:23 GMT", "version": "v1" }, { "created": "Thu, 6 Aug 2015 13:33:22 GMT", "version": "v2" } ]
2015-08-18
[ [ "Araujo", "A.", "" ], [ "Pereira", "J. G.", "" ] ]
As quotient spaces, Minkowski and de Sitter are fundamental spacetimes in the sense that they are known "a priori", independently of Einstein equation. They represent different non-gravitational backgrounds for the construction of physical theories. If general relativity is constructed on a de Sitter spacetime, the und...
2403.02056
Prosenjit Paul
Prosenjit Paul, S. I. Kruglov
Magnetic black holes in 4$D$ Einstein--Gauss--Bonnet massive gravity coupled to nonlinear electrodynamics
79 pages
null
null
null
gr-qc
http://creativecommons.org/licenses/by/4.0/
We investigate Einstein-Gauss-Bonnet (EGB) 4D massive gravity coupled to nonlinear electrodynamics (NED) in an Anti-de-Sitter (AdS) background and find an exact magnetically charged black hole solution. The metric function was analyzed for different values of massive gravity parameters. We verified the first law of b...
[ { "created": "Mon, 4 Mar 2024 13:59:56 GMT", "version": "v1" } ]
2024-03-05
[ [ "Paul", "Prosenjit", "" ], [ "Kruglov", "S. I.", "" ] ]
We investigate Einstein-Gauss-Bonnet (EGB) 4D massive gravity coupled to nonlinear electrodynamics (NED) in an Anti-de-Sitter (AdS) background and find an exact magnetically charged black hole solution. The metric function was analyzed for different values of massive gravity parameters. We verified the first law of bla...
1908.07419
Adam Pound
Adam Pound, Barry Wardell, Niels Warburton, Jeremy Miller
Second-order self-force calculation of the gravitational binding energy in compact binaries
6 pages + supplemental material, 3 figures, revised title and two added references
Phys. Rev. Lett. 124, 021101 (2020)
10.1103/PhysRevLett.124.021101
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Self-force theory is the leading method of modeling extreme-mass-ratio inspirals (EMRIs), key sources for the gravitational-wave detector LISA. It is well known that for an accurate EMRI model, second-order self-force effects are critical, but calculations of these effects have been beset by obstacles. In this letter...
[ { "created": "Tue, 20 Aug 2019 15:12:55 GMT", "version": "v1" }, { "created": "Thu, 10 Oct 2019 23:39:47 GMT", "version": "v2" }, { "created": "Tue, 19 Nov 2019 21:43:26 GMT", "version": "v3" } ]
2020-01-22
[ [ "Pound", "Adam", "" ], [ "Wardell", "Barry", "" ], [ "Warburton", "Niels", "" ], [ "Miller", "Jeremy", "" ] ]
Self-force theory is the leading method of modeling extreme-mass-ratio inspirals (EMRIs), key sources for the gravitational-wave detector LISA. It is well known that for an accurate EMRI model, second-order self-force effects are critical, but calculations of these effects have been beset by obstacles. In this letter w...
gr-qc/0009068
Hrvoje Nikolic
H. Nikolic
Fermi co-ordinates and relativistic effects in non-inertial frames
9 pages, talk presented at the conference "Physical Interpretations of Relativity Theory VII", London, September 15-18, 2000, to appear in the proceedings
null
null
null
gr-qc
null
Fermi co-ordinates are proper co-ordinates of a local observer determined by his trajectory in space-time. Two observers at different positions belong to different Fermi frames even if there is no relative motion between them. Use of Fermi co-ordinates leads to several physical conclusions related to relativistic eff...
[ { "created": "Tue, 19 Sep 2000 14:10:06 GMT", "version": "v1" } ]
2007-05-23
[ [ "Nikolic", "H.", "" ] ]
Fermi co-ordinates are proper co-ordinates of a local observer determined by his trajectory in space-time. Two observers at different positions belong to different Fermi frames even if there is no relative motion between them. Use of Fermi co-ordinates leads to several physical conclusions related to relativistic effec...
gr-qc/0205089
Jean-Paul Mbelek
J.P. Mbelek and M. Lachi\`eze-Rey
A five dimensional model of varying effective gravitational and fine structure constants
Latex2e, 10 pages with 1 Postscript figure, revised version of gr-qc/0205089, accepted for publication in Astronomy and Astrophysics. Slight changes in the figure and the figure caption, some references added
Astron.Astrophys.397:803-807,2003
10.1051/0004-6361:20021521
null
gr-qc
null
We explore the possibility that the reported time variation of the fine structure constant $\alpha$ is due to a coupling between electromagnetism and gravitation. This may reconcile the claimed results on $\alpha$ with the upper limit from the Oklo naturel Uranium fission reactor.
[ { "created": "Tue, 21 May 2002 08:59:06 GMT", "version": "v1" }, { "created": "Mon, 14 Oct 2002 14:23:41 GMT", "version": "v2" } ]
2011-05-23
[ [ "Mbelek", "J. P.", "" ], [ "Lachièze-Rey", "M.", "" ] ]
We explore the possibility that the reported time variation of the fine structure constant $\alpha$ is due to a coupling between electromagnetism and gravitation. This may reconcile the claimed results on $\alpha$ with the upper limit from the Oklo naturel Uranium fission reactor.
gr-qc/0402072
Giovanni Imponente
Giovanni Imponente and Giovanni Montani
Mixmaster Chaos via the Invariant Measure
3 pages, 1 figure, proceedings of the X Marcel Grossmann Meeting 22-26 July, 2003, Rio de Janeiro
null
10.1142/9789812704030_0220
null
gr-qc hep-th
null
The chaoticity of the Mixmaster is discussed in the framework of Statistical Mechanics by using Misner--Chitre-like variables and an ADM reduction of its dynamics. We show that such a system is well described by a microcanonical ensemble whose invariant measure is induced by the corresponding Liouville one and is uni...
[ { "created": "Mon, 16 Feb 2004 10:37:47 GMT", "version": "v1" } ]
2016-11-09
[ [ "Imponente", "Giovanni", "" ], [ "Montani", "Giovanni", "" ] ]
The chaoticity of the Mixmaster is discussed in the framework of Statistical Mechanics by using Misner--Chitre-like variables and an ADM reduction of its dynamics. We show that such a system is well described by a microcanonical ensemble whose invariant measure is induced by the corresponding Liouville one and is unifo...
2103.15884
Christos Tsagas
Christos G. Tsagas
The peculiar Jeans length
Revised and extended version. References added. Matches published manuscript
Eur. Phys. J. C 81, 753 (2021)
null
null
gr-qc astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Typical observers in the universe do not follow the smooth Hubble expansion, but move relative to it. Such bulk peculiar motions introduce a characteristic scale that is closely analogous to the familiar Jeans length. This "peculiar Jeans length" marks the threshold below which relative-motion effects dominate the li...
[ { "created": "Mon, 29 Mar 2021 18:45:20 GMT", "version": "v1" }, { "created": "Thu, 16 Sep 2021 12:10:47 GMT", "version": "v2" } ]
2021-09-17
[ [ "Tsagas", "Christos G.", "" ] ]
Typical observers in the universe do not follow the smooth Hubble expansion, but move relative to it. Such bulk peculiar motions introduce a characteristic scale that is closely analogous to the familiar Jeans length. This "peculiar Jeans length" marks the threshold below which relative-motion effects dominate the line...
2011.00984
Maksym Deliyergiyev
Antonino Del Popolo, Maksym Deliyergiyev and Morgan Le Delliou
Solution to the hyperon puzzle using dark matter
12 pp, 6 figs
Phys.Dark Univ. 30 (2020) 100622
10.1016/j.dark.2020.100622
null
gr-qc astro-ph.HE hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we studied the ``hyperon puzzle", a problem that nevertheless the large number of studies is still an open problem. The solution of this issue requires one or more mechanisms that could eventually provide the additional repulsion needed to make the EoS stiffer and, therefore, the value of $M_{\rm{max},...
[ { "created": "Mon, 2 Nov 2020 14:02:40 GMT", "version": "v1" }, { "created": "Fri, 10 Mar 2023 19:29:30 GMT", "version": "v2" } ]
2023-03-14
[ [ "Del Popolo", "Antonino", "" ], [ "Deliyergiyev", "Maksym", "" ], [ "Delliou", "Morgan Le", "" ] ]
In this paper, we studied the ``hyperon puzzle", a problem that nevertheless the large number of studies is still an open problem. The solution of this issue requires one or more mechanisms that could eventually provide the additional repulsion needed to make the EoS stiffer and, therefore, the value of $M_{\rm{max}, T...
1303.3042
Richard Woodard
H. Degueldre (MPI, Goettingen) and R. P. Woodard (U. Florida)
One Loop Field Strengths of Charges and Dipoles on a Locally de Sitter Background
35 pages, no figures, uses LaTeX 2e
null
10.1140/epjc/s10052-013-2457-z
UFIFT-QG-13-01
gr-qc astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We use the one loop vacuum polarization induced by scalar quantum electrodynamics to compute the electric and magnetic fields of point charges and magnetic dipoles on a locally de Sitter background. Our results are consistent with the physical picture of an inflating universe filling with a vast sea of charged partic...
[ { "created": "Tue, 12 Mar 2013 21:35:28 GMT", "version": "v1" } ]
2015-06-15
[ [ "Degueldre", "H.", "", "MPI, Goettingen" ], [ "Woodard", "R. P.", "", "U. Florida" ] ]
We use the one loop vacuum polarization induced by scalar quantum electrodynamics to compute the electric and magnetic fields of point charges and magnetic dipoles on a locally de Sitter background. Our results are consistent with the physical picture of an inflating universe filling with a vast sea of charged particle...
0904.1087
Larry Ford
Hongwei Yu, N.F. Svaiter and L.H. Ford
Quantum Lightcone Fluctuations in Compactified Spacetimes
28 pages, 4 figures
Phys.Rev.D80:124019,2009
10.1103/PhysRevD.80.124019
null
gr-qc hep-th quant-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We treat the effects of compactified spatial dimensions on the propagation of light in the uncompactified directions in the context of linearized quantum gravity. We find that the flight times of pulses can fluctuate due to modification of the graviton vacuum by the compactification. In the case of a five dimensional...
[ { "created": "Tue, 7 Apr 2009 09:18:10 GMT", "version": "v1" } ]
2009-12-30
[ [ "Yu", "Hongwei", "" ], [ "Svaiter", "N. F.", "" ], [ "Ford", "L. H.", "" ] ]
We treat the effects of compactified spatial dimensions on the propagation of light in the uncompactified directions in the context of linearized quantum gravity. We find that the flight times of pulses can fluctuate due to modification of the graviton vacuum by the compactification. In the case of a five dimensional K...
2302.02469
Eleonora Giovannetti
Eleonora Giovannetti and Giovanni Montani
The role of spatial curvature in constraining the Universe anisotropies across a Big Bounce
null
Eur. Phys. J. C 83, 752 (2023)
10.1140/epjc/s10052-023-11921-0
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the implementation of Polymer Quantum Mechanics (PQM) to a system decomposed into a quasi-classical background and a small quantum subsystem, according to the original Vilenkin proposal. We develop the whole formalism in the momentum representation that is the only viable in the continuum limit of the polyme...
[ { "created": "Sun, 5 Feb 2023 19:52:54 GMT", "version": "v1" }, { "created": "Thu, 16 Feb 2023 15:00:25 GMT", "version": "v2" } ]
2023-09-15
[ [ "Giovannetti", "Eleonora", "" ], [ "Montani", "Giovanni", "" ] ]
We study the implementation of Polymer Quantum Mechanics (PQM) to a system decomposed into a quasi-classical background and a small quantum subsystem, according to the original Vilenkin proposal. We develop the whole formalism in the momentum representation that is the only viable in the continuum limit of the polymer ...