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1111.4784
Aur\'elien Hees
A. Hees, A. F\"uzfa
Combined cosmological and solar system constraints on chameleon mechanism
revised version, minor changes
Phys. Rev. D, 85, 103005, 2012
10.1103/PhysRevD.85.103005
null
gr-qc astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Chameleon mechanism appearing in massive tensor-scalar theory of gravity can effectively reduce locally the non-minimal coupling between the scalar field and matter. This mechanism is invoked to reconcile large-scale departures from general relativity (GR), supposedly accounting for cosmic acceleration, to small scal...
[ { "created": "Mon, 21 Nov 2011 08:24:43 GMT", "version": "v1" }, { "created": "Thu, 10 May 2012 21:31:13 GMT", "version": "v2" } ]
2015-03-19
[ [ "Hees", "A.", "" ], [ "Füzfa", "A.", "" ] ]
Chameleon mechanism appearing in massive tensor-scalar theory of gravity can effectively reduce locally the non-minimal coupling between the scalar field and matter. This mechanism is invoked to reconcile large-scale departures from general relativity (GR), supposedly accounting for cosmic acceleration, to small scales...
1403.2600
Tomasz Miller
M. Heller, T. Miller, L. Pysiak, W. Sasin
Geometry and General Relativity in the Groupoid Model with a Finite Structure Group
32 pages
Can. J Phys., 2015, 93(1): 43-54
10.1139/cjp-2014-0145
null
gr-qc math-ph math.MP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In a series of papers we proposed a model unifying general relativity and quantum mechanics. The idea was to deduce both general relativity and quantum mechanics from a noncommutative algebra ${\cal A}_{\Gamma}$ defined on a transformation groupoid $\Gamma$ determined by the action of the Lorentz group on the frame b...
[ { "created": "Tue, 11 Mar 2014 15:04:12 GMT", "version": "v1" }, { "created": "Thu, 8 Jan 2015 13:26:42 GMT", "version": "v2" } ]
2015-01-09
[ [ "Heller", "M.", "" ], [ "Miller", "T.", "" ], [ "Pysiak", "L.", "" ], [ "Sasin", "W.", "" ] ]
In a series of papers we proposed a model unifying general relativity and quantum mechanics. The idea was to deduce both general relativity and quantum mechanics from a noncommutative algebra ${\cal A}_{\Gamma}$ defined on a transformation groupoid $\Gamma$ determined by the action of the Lorentz group on the frame bun...
gr-qc/0305028
Sawa Manoff
Sawa Manoff
Null vector fields in spaces with affine connections and metrics. Doppler's effect, Hubble's effect, and aberration's effect
33 pages, LaTeX
null
null
null
gr-qc
null
The notion of null (isotropic) vector field is considered in spaces with affine connections and metrics as models of space or space-time. On its basis the propagation of signals in space-time is considered. The Doppler effect is generalized for these types of spaces. The notions of standard (longitudinal) Doppler eff...
[ { "created": "Wed, 7 May 2003 15:54:54 GMT", "version": "v1" } ]
2007-05-23
[ [ "Manoff", "Sawa", "" ] ]
The notion of null (isotropic) vector field is considered in spaces with affine connections and metrics as models of space or space-time. On its basis the propagation of signals in space-time is considered. The Doppler effect is generalized for these types of spaces. The notions of standard (longitudinal) Doppler effec...
1204.2965
Mauro Sereno
N. Radicella (UAB), M. Sereno (POLITO, INFN), A. Tartaglia (POLITO, INFN)
Spherical symmetry in a dark energy permeated space-time
14 pages, 1 figure, in press on Classical and Quantum Gravity
null
10.1088/0264-9381/29/11/115003
null
gr-qc astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The properties of a spherically symmetric static space-time permeated of dark energy are worked out. Dark energy is viewed as the strain energy of an elastically deformable four dimensional manifold. The metric is worked out in the vacuum region around a central spherical mass/defect in the linear approximation. We d...
[ { "created": "Fri, 13 Apr 2012 12:07:58 GMT", "version": "v1" } ]
2015-06-04
[ [ "Radicella", "N.", "", "UAB" ], [ "Sereno", "M.", "", "POLITO, INFN" ], [ "Tartaglia", "A.", "", "POLITO,\n INFN" ] ]
The properties of a spherically symmetric static space-time permeated of dark energy are worked out. Dark energy is viewed as the strain energy of an elastically deformable four dimensional manifold. The metric is worked out in the vacuum region around a central spherical mass/defect in the linear approximation. We dis...
1005.2328
Ivan Agullo
Ivan Agullo, Jose Navarro-Salas, Gonzalo J. Olmo, Leonard Parker
Reply to "Comment on 'Insensitivity of Hawking radiation to an invariant Planck-scale cutoff' "
3 pages, to appear in Phys. Rev. D.
Phys.Rev.D81:108502,2010
10.1103/PhysRevD.81.108502
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We clarify the relationship between the conclusions of the previous Comment of A. Helfer [1] and that of our Brief Report [arXiv:0906.5315]
[ { "created": "Thu, 13 May 2010 14:25:05 GMT", "version": "v1" } ]
2014-11-21
[ [ "Agullo", "Ivan", "" ], [ "Navarro-Salas", "Jose", "" ], [ "Olmo", "Gonzalo J.", "" ], [ "Parker", "Leonard", "" ] ]
We clarify the relationship between the conclusions of the previous Comment of A. Helfer [1] and that of our Brief Report [arXiv:0906.5315]
1110.5950
Leo Stein
Kent Yagi, Leo C. Stein, Nicolas Yunes, Takahiro Tanaka
Post-Newtonian, Quasi-Circular Binary Inspirals in Quadratic Modified Gravity
26 pages, 3 figures, 2 tables (matches version published in PRD); v3 prepended an erratum
Phys. Rev. D 85, 064022 (2012); Phys. Rev. D 93, 029902 (2016)
10.1103/PhysRevD.85.064022 10.1103/PhysRevD.93.029902
null
gr-qc astro-ph.CO hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider a general class of quantum gravity-inspired, modified gravity theories, where the Einstein-Hilbert action is extended through the addition of all terms quadratic in the curvature tensor coupled to scalar fields with standard kinetic energy. This class of theories includes Einstein-Dilaton-Gauss-Bonnet and...
[ { "created": "Thu, 27 Oct 2011 00:13:28 GMT", "version": "v1" }, { "created": "Mon, 16 Apr 2012 02:31:15 GMT", "version": "v2" }, { "created": "Wed, 2 Dec 2015 22:27:57 GMT", "version": "v3" } ]
2016-04-12
[ [ "Yagi", "Kent", "" ], [ "Stein", "Leo C.", "" ], [ "Yunes", "Nicolas", "" ], [ "Tanaka", "Takahiro", "" ] ]
We consider a general class of quantum gravity-inspired, modified gravity theories, where the Einstein-Hilbert action is extended through the addition of all terms quadratic in the curvature tensor coupled to scalar fields with standard kinetic energy. This class of theories includes Einstein-Dilaton-Gauss-Bonnet and C...
2402.07213
Hichem Guergouri
Omar Nemoul, Hichem Guergouri, Jamal Mimouni
Non-Radial Free Geodesics. II. In Spatially Curved FLRW Spacetime
17 pages
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper presents an in-depth exploration of timelike free geodesics in spatially curved Friedmann-Lema\^itre-Robertson-Walker (FLRW) spacetime. A unified approach for these geodesics encompassing both radial and non-radial trajectories across Euclidean, spherical, and hyperbolic geometries is employed. Using the s...
[ { "created": "Sun, 11 Feb 2024 14:21:22 GMT", "version": "v1" } ]
2024-02-13
[ [ "Nemoul", "Omar", "" ], [ "Guergouri", "Hichem", "" ], [ "Mimouni", "Jamal", "" ] ]
This paper presents an in-depth exploration of timelike free geodesics in spatially curved Friedmann-Lema\^itre-Robertson-Walker (FLRW) spacetime. A unified approach for these geodesics encompassing both radial and non-radial trajectories across Euclidean, spherical, and hyperbolic geometries is employed. Using the sym...
1808.04674
Vasilis Oikonomou
K. Kleidis, V.K. Oikonomou
Autonomous Dynamical System Description of de Sitter Evolution in Scalar Assisted $f(R)-\phi$ Gravity
null
null
10.1142/S0219887818502122
null
gr-qc astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this letter we will study the cosmological dynamical system of an $f(R)$ gravity in the presence of a canonical scalar field $\phi$ with an exponential potential, by constructing the dynamical system in a way that it is render autonomous. This feature is controlled by a single variable $m$, which when it is consta...
[ { "created": "Tue, 14 Aug 2018 13:23:56 GMT", "version": "v1" } ]
2019-01-09
[ [ "Kleidis", "K.", "" ], [ "Oikonomou", "V. K.", "" ] ]
In this letter we will study the cosmological dynamical system of an $f(R)$ gravity in the presence of a canonical scalar field $\phi$ with an exponential potential, by constructing the dynamical system in a way that it is render autonomous. This feature is controlled by a single variable $m$, which when it is constant...
0801.4342
Sushant Ghosh
S. G. Ghosh and A. K. Dawood
Radiating black hole solutions in arbitrary dimensions
RevTeX 9 pages, no figures
Gen.Rel.Grav.40:9-21,2008
10.1007/s10714-007-0511-6
null
gr-qc
null
We prove a theorem that characterizes a large family of non-static solutions to Einstein equations in $N$-dimensional space-time, representing, in general, spherically symmetric Type II fluid. It is shown that the best known Vaidya-based (radiating) black hole solutions to Einstein equations, in both four dimensions ...
[ { "created": "Mon, 28 Jan 2008 17:59:25 GMT", "version": "v1" } ]
2008-11-26
[ [ "Ghosh", "S. G.", "" ], [ "Dawood", "A. K.", "" ] ]
We prove a theorem that characterizes a large family of non-static solutions to Einstein equations in $N$-dimensional space-time, representing, in general, spherically symmetric Type II fluid. It is shown that the best known Vaidya-based (radiating) black hole solutions to Einstein equations, in both four dimensions (4...
1111.0912
John Morris
J. R. Morris
Dilatonic effects near naked singularities
13 pages
null
10.1007/s10714-011-1282-7
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Static spherically symmetric solutions of 4d Brans-Dicke theory include a set of naked singularity solutions. Dilatonic effects near the naked singularities result in either a shielding or an antishielding effect from intruding massive test particles. One result is that for a portion of the solution parameter space, ...
[ { "created": "Thu, 3 Nov 2011 16:53:31 GMT", "version": "v1" } ]
2015-06-03
[ [ "Morris", "J. R.", "" ] ]
Static spherically symmetric solutions of 4d Brans-Dicke theory include a set of naked singularity solutions. Dilatonic effects near the naked singularities result in either a shielding or an antishielding effect from intruding massive test particles. One result is that for a portion of the solution parameter space, no...
gr-qc/0405079
Carlos Augusto Romero Filho
J.J.Figueiredo and C.Romero
Kaluza-Klein gravity in the context of modern embedding theories of spacetime
12 pages - Typeset using REVTEX
Grav.Cosmol.10:187-190,2004
null
null
gr-qc
null
We review and discuss the original Kaluza-Klein theory in the framework of modern embedding theories of the spacetime, such as the recent induced matter approach. We show that in spite of their seeming similarity they constitute rather distinct proposals as far as their geometrical structure is concerned.
[ { "created": "Sat, 15 May 2004 13:50:40 GMT", "version": "v1" } ]
2011-07-19
[ [ "Figueiredo", "J. J.", "" ], [ "Romero", "C.", "" ] ]
We review and discuss the original Kaluza-Klein theory in the framework of modern embedding theories of the spacetime, such as the recent induced matter approach. We show that in spite of their seeming similarity they constitute rather distinct proposals as far as their geometrical structure is concerned.
gr-qc/0606052
Luis Herrera
L. Herrera, A. Di Prisco, J. Carot and N.O. Santos
Energetics of the Einstein-Rosen spacetime
19 pages Latex.References added and updated.To appear in Int.J.Theor.Phys
Int.J.Theor.Phys.47:380,2008
10.1007/s10773-007-9460-9
null
gr-qc
null
A study covering some aspects of the Einstein--Rosen metric is presented. The electric and magnetic parts of the Weyl tensor are calculated. It is shown that there are no purely magnetic E--R spacetimes, and also that a purely electric E--R spacetime is necessarily static. The geodesics equations are found and circul...
[ { "created": "Mon, 12 Jun 2006 18:27:53 GMT", "version": "v1" }, { "created": "Mon, 16 Apr 2007 19:37:22 GMT", "version": "v2" } ]
2008-11-26
[ [ "Herrera", "L.", "" ], [ "Di Prisco", "A.", "" ], [ "Carot", "J.", "" ], [ "Santos", "N. O.", "" ] ]
A study covering some aspects of the Einstein--Rosen metric is presented. The electric and magnetic parts of the Weyl tensor are calculated. It is shown that there are no purely magnetic E--R spacetimes, and also that a purely electric E--R spacetime is necessarily static. The geodesics equations are found and circular...
1901.00218
Gon\c{c}alo Quinta
Gon\c{c}alo M. Quinta, Antonino Flachi, Jos\'e P. S. Lemos
Spontaneously broken symmetry restoration of quantum fields in the vicinity of neutral and electrically charged black holes
16 pages, 4 figures
JHEP 04 (2019) 139
10.1007/JHEP04(2019)139
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider the restoration of a spontaneously broken symmetry of an interacting quantum scalar field around neutral, i.e., Schwarzschild, and electrically charged, i.e., Reissner-Nordstr\"om, black holes in four dimensions. This is done through a semiclassical self-consistent procedure, by solving the system of non-...
[ { "created": "Tue, 1 Jan 2019 22:54:33 GMT", "version": "v1" } ]
2019-09-25
[ [ "Quinta", "Gonçalo M.", "" ], [ "Flachi", "Antonino", "" ], [ "Lemos", "José P. S.", "" ] ]
We consider the restoration of a spontaneously broken symmetry of an interacting quantum scalar field around neutral, i.e., Schwarzschild, and electrically charged, i.e., Reissner-Nordstr\"om, black holes in four dimensions. This is done through a semiclassical self-consistent procedure, by solving the system of non-li...
2006.16821
Grigory Volovik
G.E. Volovik
Dimensionless physics
8 pages, no figures, extended version of arXiv:2003.00915, draft prepared for the issue of JETP devoted to Dzyaloshinskii-90
null
10.1134/S106377612104021X
null
gr-qc cond-mat.str-el hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss two scenarios of emergent gravity. In one of them the quantum vacuum is considered as superplastic crystal, and the effective gravity describes the dynamical elastic deformations of this crystal. In the other one the gravitational tetrads emerge as the bilinear form of the fermionic fields. In spite of the...
[ { "created": "Tue, 30 Jun 2020 13:59:34 GMT", "version": "v1" }, { "created": "Thu, 2 Jul 2020 11:07:57 GMT", "version": "v2" }, { "created": "Wed, 8 Jul 2020 15:12:55 GMT", "version": "v3" }, { "created": "Sun, 19 Jul 2020 17:35:55 GMT", "version": "v4" }, { "cre...
2021-06-16
[ [ "Volovik", "G. E.", "" ] ]
We discuss two scenarios of emergent gravity. In one of them the quantum vacuum is considered as superplastic crystal, and the effective gravity describes the dynamical elastic deformations of this crystal. In the other one the gravitational tetrads emerge as the bilinear form of the fermionic fields. In spite of the e...
2212.09896
Ioannis Gialamas
Ioannis D. Gialamas, Kyriakos Tamvakis
Inflation in Metric-Affine Quadratic Gravity
21 pages, 7 figures, 3 tables, JCAP accepted version
JCAP 03 (2023) 042
10.1088/1475-7516/2023/03/042
null
gr-qc astro-ph.CO hep-th
http://creativecommons.org/licenses/by/4.0/
In the general framework of Metric-Affine theories of gravity, where the metric and the connection are independent variables, we consider actions quadratic in the Ricci scalar curvature and the Holst invariant (the contraction of the Riemann curvature with the Levi-Civita antisymmetric tensor) coupled non-minimally t...
[ { "created": "Mon, 19 Dec 2022 22:37:43 GMT", "version": "v1" }, { "created": "Wed, 15 Mar 2023 15:06:25 GMT", "version": "v2" } ]
2023-03-21
[ [ "Gialamas", "Ioannis D.", "" ], [ "Tamvakis", "Kyriakos", "" ] ]
In the general framework of Metric-Affine theories of gravity, where the metric and the connection are independent variables, we consider actions quadratic in the Ricci scalar curvature and the Holst invariant (the contraction of the Riemann curvature with the Levi-Civita antisymmetric tensor) coupled non-minimally to ...
gr-qc/9507002
Roberto Emparan
R. Emparan
Correlations between black holes formed in cosmic string breaking
11 pages, LaTeX. Final version, to appear in Phys. Rev. D
Phys.Rev. D52 (1995) 6976-6981
10.1103/PhysRevD.52.6976
EHU-FT/9511
gr-qc hep-th
null
An analysis of cosmic string breaking with the formation of black holes attached to the ends reveals a remarkable feature: the black holes can be correlated or uncorrelated. We find that, as a consequence, the number-of-states enhancement factor in the action governing the formation of uncorrelated black holes is twi...
[ { "created": "Mon, 3 Jul 1995 18:22:48 GMT", "version": "v1" }, { "created": "Wed, 8 Nov 1995 16:27:52 GMT", "version": "v2" } ]
2009-10-28
[ [ "Emparan", "R.", "" ] ]
An analysis of cosmic string breaking with the formation of black holes attached to the ends reveals a remarkable feature: the black holes can be correlated or uncorrelated. We find that, as a consequence, the number-of-states enhancement factor in the action governing the formation of uncorrelated black holes is twice...
gr-qc/0401003
Uwe Gunther
Uwe Guenther, Alexander Zhuk
Remarks on dimensional reduction of multidimensional cosmological models
9 pages, Latex2e, Conf. Proc., Tenth Marcel Grossmann Meeting on General Relativity, July 20-26, 2003, Rio de Janeiro, Brazil, presentation and references extended
null
10.1142/9789812704030_0052
null
gr-qc hep-ph hep-th
null
Multidimensional cosmological models with factorizable geometry and their dimensional reduction to effective four-dimensional theories are analyzed on sensitivity to different scalings. It is shown that a non-correct gauging of the effective four-dimensional gravitational constant within the dimensional reduction res...
[ { "created": "Fri, 2 Jan 2004 14:27:51 GMT", "version": "v1" }, { "created": "Tue, 9 Mar 2004 13:40:05 GMT", "version": "v2" } ]
2016-11-09
[ [ "Guenther", "Uwe", "" ], [ "Zhuk", "Alexander", "" ] ]
Multidimensional cosmological models with factorizable geometry and their dimensional reduction to effective four-dimensional theories are analyzed on sensitivity to different scalings. It is shown that a non-correct gauging of the effective four-dimensional gravitational constant within the dimensional reduction resul...
2212.08694
Simone Mastrogiovanni
Jonathan R. Gair, Archisman Ghosh, Rachel Gray, Daniel E. Holz, Simone Mastrogiovanni, Suvodip Mukherjee, Antonella Palmese, Nicola Tamanini, Tessa Baker, Freija Beirnaert, Maciej Bilicki, Hsin-Yu Chen, Gergely D\'alya, Jose Maria Ezquiaga, Will M. Farr, Maya Fishbach, Juan Garcia-Bellido, Tathagata Ghosh, Hsia...
The Hitchhiker's guide to the galaxy catalog approach for gravitational wave cosmology
19 pages, 11 figures. Submitted to ApJ
null
10.3847/1538-3881/acca78
null
gr-qc astro-ph.CO
http://creativecommons.org/licenses/by/4.0/
We outline the ``dark siren'' galaxy catalog method for cosmological inference using gravitational wave (GW) standard sirens, clarifying some common misconceptions in the implementation of this method. When a confident transient electromagnetic counterpart to a GW event is unavailable, the identification of a unique ...
[ { "created": "Fri, 16 Dec 2022 19:44:18 GMT", "version": "v1" } ]
2023-06-28
[ [ "Gair", "Jonathan R.", "" ], [ "Ghosh", "Archisman", "" ], [ "Gray", "Rachel", "" ], [ "Holz", "Daniel E.", "" ], [ "Mastrogiovanni", "Simone", "" ], [ "Mukherjee", "Suvodip", "" ], [ "Palmese", "Antonella", ...
We outline the ``dark siren'' galaxy catalog method for cosmological inference using gravitational wave (GW) standard sirens, clarifying some common misconceptions in the implementation of this method. When a confident transient electromagnetic counterpart to a GW event is unavailable, the identification of a unique ho...
gr-qc/9707015
O. B. Zaslavskii
O.B.Zaslavskii
Geometry of nonextreme black holes near the extreme state
10 pages, Revtex 3.0. To be published in Phys.Rev.D
Phys.Rev.D56:2188-2191,1997; Erratum-ibid.D59:069901,1999
10.1103/PhysRevD.56.2188 10.1103/PhysRevD.59.069901
null
gr-qc hep-th
null
Nonextreme black hole in a cavity can achieve the extreme state with a zero surface gravity at a finite temperature on a boundary, the proper distance between the boundary and the horizon being finite. The classical geometry in this state is found explicitly for four-dimensional spherically-symmetrical and 2+1 rotati...
[ { "created": "Wed, 2 Jul 1997 12:49:38 GMT", "version": "v1" } ]
2014-11-17
[ [ "Zaslavskii", "O. B.", "" ] ]
Nonextreme black hole in a cavity can achieve the extreme state with a zero surface gravity at a finite temperature on a boundary, the proper distance between the boundary and the horizon being finite. The classical geometry in this state is found explicitly for four-dimensional spherically-symmetrical and 2+1 rotating...
1908.06023
Stefano Viaggiu
Stefano Viaggiu
The physical origin of the cosmological constant: continuum limit and the analogy with the Casimir effect
Accepted on Physica Scripta
null
10.1088/1402-4896/ab3d02
null
gr-qc astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we continue the investigations in \cite{1} concerning the origin of the cosmological constant. First of all, we generalise the results in \cite{1,2} by considering a continuum approximation for a radiation field in a cosmological background. In this way, we clearly show that the bare cosmological consta...
[ { "created": "Thu, 15 Aug 2019 11:26:50 GMT", "version": "v1" }, { "created": "Thu, 22 Aug 2019 15:19:01 GMT", "version": "v2" } ]
2019-08-23
[ [ "Viaggiu", "Stefano", "" ] ]
In this paper we continue the investigations in \cite{1} concerning the origin of the cosmological constant. First of all, we generalise the results in \cite{1,2} by considering a continuum approximation for a radiation field in a cosmological background. In this way, we clearly show that the bare cosmological constant...
gr-qc/9303003
Marina Strakhova
A. Burinskii
String-Like Structures in Complex Kerr Geometry
12 pages, AmS-TeX, Talk given at the Fourth Hungarian Relativity Workshop organized by R.P. Kerr and Z. Perj\'es, G\'ardony, 12-17 July 1992
null
null
Preprint NSI-8-93
gr-qc hep-th
null
The Kerr geometry is represented as being created by a source moving along an analytical complex world-line. The equivalence of this complex world-line and an Euclidean version of complex strings (hyperbolic strings) is discussed. It is shown that the complex Kerr source satisfies the corresponding string equations. ...
[ { "created": "Mon, 1 Mar 1993 13:42:21 GMT", "version": "v1" } ]
2007-05-23
[ [ "Burinskii", "A.", "" ] ]
The Kerr geometry is represented as being created by a source moving along an analytical complex world-line. The equivalence of this complex world-line and an Euclidean version of complex strings (hyperbolic strings) is discussed. It is shown that the complex Kerr source satisfies the corresponding string equations. Th...
gr-qc/0302002
Luis Augusto Trevisan
Luis Augusto Trevisan
A numerical analysis for G(t) in a scalar tensor theory
The 4 figures (ps files) were included
null
null
null
gr-qc
null
We calculated the evolution of the Newton gravitational in a scalar tensor theory, using parameters that holds for the present Universe. We analised the evolution from one billion of years ago.
[ { "created": "Mon, 3 Feb 2003 20:00:43 GMT", "version": "v1" }, { "created": "Tue, 4 Feb 2003 16:42:23 GMT", "version": "v2" } ]
2007-05-23
[ [ "Trevisan", "Luis Augusto", "" ] ]
We calculated the evolution of the Newton gravitational in a scalar tensor theory, using parameters that holds for the present Universe. We analised the evolution from one billion of years ago.
2408.05957
Peng-Cheng Li
Tao Zhou and Peng-Cheng Li
Quasinormal modes of accelerating spacetime
12 pages. arXiv admin note: text overlap with arXiv:gr-qc/0605027 by other authors
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We calculate the exact values of the quasinormal frequencies for massless perturbations with spin $s\leq2$ moving in pure accelerating spacetime. We use two different methods to transfer the perturbation equations into the form of hypergeometric differential equations and obtain the same quasinormal frequencies. Thes...
[ { "created": "Mon, 12 Aug 2024 07:19:33 GMT", "version": "v1" } ]
2024-08-13
[ [ "Zhou", "Tao", "" ], [ "Li", "Peng-Cheng", "" ] ]
We calculate the exact values of the quasinormal frequencies for massless perturbations with spin $s\leq2$ moving in pure accelerating spacetime. We use two different methods to transfer the perturbation equations into the form of hypergeometric differential equations and obtain the same quasinormal frequencies. These ...
gr-qc/0311050
Tiberiu Harko
M. K. Mak, T. Harko
Full causal dissipative cosmologies with stiff matter
6 pages, 6 figures, to appear in Int. J. Mod. Phys. D
Int.J.Mod.Phys.D13:273-280,2004
10.1142/S0218271804004645
null
gr-qc
null
The general solution of the gravitational field equations for a full causal bulk viscous stiff cosmological fluid, with bulk viscosity coefficient proportional to the energy density to the power 1/4, is obtained in the flat Friedmann-Robertson-Walker geometry. The solution describes a non-inflationary Universe, which...
[ { "created": "Sat, 15 Nov 2003 02:15:09 GMT", "version": "v1" } ]
2008-11-26
[ [ "Mak", "M. K.", "" ], [ "Harko", "T.", "" ] ]
The general solution of the gravitational field equations for a full causal bulk viscous stiff cosmological fluid, with bulk viscosity coefficient proportional to the energy density to the power 1/4, is obtained in the flat Friedmann-Robertson-Walker geometry. The solution describes a non-inflationary Universe, which s...
2308.12827
Kristen Lackeos
Kristen Lackeos, Tyson B. Littenberg, Neil J. Cornish, James I. Thorpe
The LISA Data Challenge Radler Analysis and Time-dependent Ultra-compact Binary Catalogues
null
A&A 678, A123 (2023)
10.1051/0004-6361/202347222
null
gr-qc
http://creativecommons.org/licenses/by/4.0/
Context. Galactic binaries account for the loudest combined continuous gravitational wave signal in the Laser Interferometer Space Antenna (LISA) band, which spans a frequency range of 0.1 mHz to 1 Hz. Aims. A superposition of low frequency Galactic and extragalactic signals and instrument noise comprise the LISA d...
[ { "created": "Thu, 24 Aug 2023 14:34:37 GMT", "version": "v1" } ]
2023-10-18
[ [ "Lackeos", "Kristen", "" ], [ "Littenberg", "Tyson B.", "" ], [ "Cornish", "Neil J.", "" ], [ "Thorpe", "James I.", "" ] ]
Context. Galactic binaries account for the loudest combined continuous gravitational wave signal in the Laser Interferometer Space Antenna (LISA) band, which spans a frequency range of 0.1 mHz to 1 Hz. Aims. A superposition of low frequency Galactic and extragalactic signals and instrument noise comprise the LISA data ...
1312.1018
Israel Quiros
Israel Quiros
Scale invariance and broken electroweak symmetry may coexist together
5 pages, no figures. Sustantial improvements: (i) the discussion on generation of mass hierarchy complemented with necessary statements about the measurable quantities in Weyl spaces, and (ii) unnecessary discussion on the coosmological constant, not relevant to the main focus of the paper removed
null
null
null
gr-qc hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Here we show that local scale invariance -- invariance under Weyl rescalings -- may safely coexist with broken electroweak symmetry if assume the Weyl geometric theory to govern the affine structure of spacetime. We find that within the resulting scale invariant theory of gravity cosmological inflation is enough to e...
[ { "created": "Wed, 4 Dec 2013 04:11:29 GMT", "version": "v1" }, { "created": "Sun, 8 Dec 2013 22:42:48 GMT", "version": "v2" }, { "created": "Fri, 3 Jan 2014 05:12:04 GMT", "version": "v3" } ]
2014-01-06
[ [ "Quiros", "Israel", "" ] ]
Here we show that local scale invariance -- invariance under Weyl rescalings -- may safely coexist with broken electroweak symmetry if assume the Weyl geometric theory to govern the affine structure of spacetime. We find that within the resulting scale invariant theory of gravity cosmological inflation is enough to exp...
1805.01004
Moritz Reintjes
Moritz Reintjes and Blake Temple
The Regularity Transformation Equations: An elliptic mechanism for smoothing gravitational metrics in General Relativity
Version 5: Subsections are promoted to sections. Version 3 & 4: Improved wording, results unchanged. Version 2: We improved our main result, Theorem 1.1, by replacing the problematic boundary data (1.5) with linear data (eqn (1.5) in V.2), and we replaced eqns (1.1) - (1.2) of V.1 with the Poisson equation (3.5...
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A central question in General Relativity (GR) is how to determine whether singularities are geometrical properties of spacetime, or simply anomalies of a coordinate system used to parameterize the spacetime. In particular, it is an open problem whether there always exist coordinate transformations which smooth a grav...
[ { "created": "Wed, 2 May 2018 20:28:55 GMT", "version": "v1" }, { "created": "Wed, 23 May 2018 21:50:36 GMT", "version": "v2" }, { "created": "Mon, 24 Sep 2018 12:30:09 GMT", "version": "v3" }, { "created": "Thu, 9 May 2019 04:05:38 GMT", "version": "v4" }, { "cre...
2020-11-10
[ [ "Reintjes", "Moritz", "" ], [ "Temple", "Blake", "" ] ]
A central question in General Relativity (GR) is how to determine whether singularities are geometrical properties of spacetime, or simply anomalies of a coordinate system used to parameterize the spacetime. In particular, it is an open problem whether there always exist coordinate transformations which smooth a gravit...
gr-qc/0312104
Elizabeth Winstanley
Tom J.T. Harper, Paul A. Thomas, Elizabeth Winstanley and Phil M. Young
Instability of a four-dimensional de Sitter black hole with a conformally coupled scalar field
revtex4, 8 pages, 4 figures, minor changes, accepted for publication in Phys. Rev. D
Phys.Rev. D70 (2004) 064023
10.1103/PhysRevD.70.064023
null
gr-qc
null
We study the stability of new neutral and electrically charged four-dimensional black hole solutions of Einstein's equations with a positive cosmological constant and conformally coupled scalar field. The neutral black holes are always unstable. The charged black holes are also shown analytically to be unstable for t...
[ { "created": "Tue, 23 Dec 2003 14:02:54 GMT", "version": "v1" }, { "created": "Wed, 11 Aug 2004 09:00:59 GMT", "version": "v2" } ]
2009-11-10
[ [ "Harper", "Tom J. T.", "" ], [ "Thomas", "Paul A.", "" ], [ "Winstanley", "Elizabeth", "" ], [ "Young", "Phil M.", "" ] ]
We study the stability of new neutral and electrically charged four-dimensional black hole solutions of Einstein's equations with a positive cosmological constant and conformally coupled scalar field. The neutral black holes are always unstable. The charged black holes are also shown analytically to be unstable for the...
gr-qc/9804011
CJ Fewster
C.J. Fewster (Department of Mathematics, University of York)
A Unique Continuation Result for Klein-Gordon Bisolutions on a 2-dimensional Cylinder
LaTeX2e, 9 pages
Class.Quant.Grav.16:789-796,1999
10.1088/0264-9381/16/3/011
null
gr-qc
null
We prove a novel unique continuation result for weak bisolutions to the massive Klein-Gordon equation on a 2-dimensional cylinder M. Namely, if such a bisolution vanishes in a neighbourhood of a `sufficiently large' portion of a 2-dimensional surface lying parallel to the diagonal in the product manifold of M with it...
[ { "created": "Fri, 3 Apr 1998 17:37:11 GMT", "version": "v1" } ]
2008-11-26
[ [ "Fewster", "C. J.", "", "Department of Mathematics, University of York" ] ]
We prove a novel unique continuation result for weak bisolutions to the massive Klein-Gordon equation on a 2-dimensional cylinder M. Namely, if such a bisolution vanishes in a neighbourhood of a `sufficiently large' portion of a 2-dimensional surface lying parallel to the diagonal in the product manifold of M with itse...
1303.2381
Orfeu Bertolami
Orfeu Bertolami
Zen and the Art of Space-Time Manufacturing
Talk delivered at the Time Machine Factory conference, 14-19 October 2012, Turin, Italy
null
10.1051/epjconf/20135802001
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a general discussion about the so-called emergent properties and discuss whether space-time and gravity can be regarded as emergent features of underlying more fundamental structures. Finally, we discuss some ideas about the multiverse, and speculate on how our universe might arise from the multiverse.
[ { "created": "Sun, 10 Mar 2013 21:51:57 GMT", "version": "v1" } ]
2017-03-22
[ [ "Bertolami", "Orfeu", "" ] ]
We present a general discussion about the so-called emergent properties and discuss whether space-time and gravity can be regarded as emergent features of underlying more fundamental structures. Finally, we discuss some ideas about the multiverse, and speculate on how our universe might arise from the multiverse.
0810.1790
Takashi Torii
Takashi Torii, Hisa-aki Shinkai
$N+1$ formalism in Einstein-Gauss-Bonnet gravity
15pages, no figure, to appear in PRD
Phys.Rev.D78:084037,2008
10.1103/PhysRevD.78.084037
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Towards the investigation of the full dynamics in higher-dimensional and/or stringy gravitational model, we present the basic equations of the Einstein-Gauss-Bonnet gravity theory. We show $(N+1)$-dimensional version of the ADM decomposition including Gauss-Bonnet terms, which shall be the standard approach to treat ...
[ { "created": "Fri, 10 Oct 2008 01:22:44 GMT", "version": "v1" } ]
2008-11-26
[ [ "Torii", "Takashi", "" ], [ "Shinkai", "Hisa-aki", "" ] ]
Towards the investigation of the full dynamics in higher-dimensional and/or stringy gravitational model, we present the basic equations of the Einstein-Gauss-Bonnet gravity theory. We show $(N+1)$-dimensional version of the ADM decomposition including Gauss-Bonnet terms, which shall be the standard approach to treat th...
1108.4791
Patryk Mach
Patryk Mach and Walter Simon
(In)finite extent of stationary perfect fluids in Newtonian theory
Corrections according to the version accepted by Ann. Henri Poincare
null
10.1007/s00023-012-0181-0
null
gr-qc astro-ph.SR math-ph math.MP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
For stationary, barotropic fluids in Newtonian gravity we give simple criteria on the equation of state and the "law of motion" which guarantee finite or infinite extent of the fluid region (providing a priori estimates for the corresponding stationary Newton-Euler system). Under more restrictive conditions, we can a...
[ { "created": "Wed, 24 Aug 2011 09:12:03 GMT", "version": "v1" }, { "created": "Sat, 28 Apr 2012 16:38:50 GMT", "version": "v2" } ]
2012-05-01
[ [ "Mach", "Patryk", "" ], [ "Simon", "Walter", "" ] ]
For stationary, barotropic fluids in Newtonian gravity we give simple criteria on the equation of state and the "law of motion" which guarantee finite or infinite extent of the fluid region (providing a priori estimates for the corresponding stationary Newton-Euler system). Under more restrictive conditions, we can als...
2305.19336
Simone Albanesi
Simone Albanesi, Sebastiano Bernuzzi, Thibault Damour, Alessandro Nagar, Andrea Placidi
Faithful effective-one-body waveform of small-mass-ratio coalescing black hole binaries: the eccentric, nonspinning, case
23+6 pages, 20+3 figures, updated according to published version (PRD)
null
10.1103/PhysRevD.108.084037
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a new effective-one-body (EOB) waveform for eccentric, nonspinning, binaries in the extreme mass ratio limit, with initial eccentricities up to $0.95$. The EOB analytical waveform, that includes noncircular corrections up to second post-Newtonian order, is completed by a phenomenological ringdown model tha...
[ { "created": "Tue, 30 May 2023 18:03:42 GMT", "version": "v1" }, { "created": "Mon, 23 Oct 2023 16:27:03 GMT", "version": "v2" } ]
2023-10-24
[ [ "Albanesi", "Simone", "" ], [ "Bernuzzi", "Sebastiano", "" ], [ "Damour", "Thibault", "" ], [ "Nagar", "Alessandro", "" ], [ "Placidi", "Andrea", "" ] ]
We present a new effective-one-body (EOB) waveform for eccentric, nonspinning, binaries in the extreme mass ratio limit, with initial eccentricities up to $0.95$. The EOB analytical waveform, that includes noncircular corrections up to second post-Newtonian order, is completed by a phenomenological ringdown model that ...
gr-qc/0401019
Carlos Palenzuela
C. Bona and C. Palenzuela
Dynamical shift conditions for the Z4 and BSSN hyperbolic formalisms
text changed, accepted in PRD
Phys.Rev.D69:104003,2004
10.1103/PhysRevD.69.104003
null
gr-qc
null
A class of dynamical shift conditions is shown to lead to a strongly hyperbolic evolution system, both in the Z4 and in the BSSN Numerical Relativity formalisms. This class generalizes the harmonic shift condition, where light speed is the only non-trivial characteristic speed, and it is contained into the multi-para...
[ { "created": "Wed, 7 Jan 2004 11:19:44 GMT", "version": "v1" }, { "created": "Mon, 22 Mar 2004 10:46:01 GMT", "version": "v2" } ]
2011-04-21
[ [ "Bona", "C.", "" ], [ "Palenzuela", "C.", "" ] ]
A class of dynamical shift conditions is shown to lead to a strongly hyperbolic evolution system, both in the Z4 and in the BSSN Numerical Relativity formalisms. This class generalizes the harmonic shift condition, where light speed is the only non-trivial characteristic speed, and it is contained into the multi-parame...
2008.03817
Matt Visser
Joshua Baines (Victoria University of Wellington), Thomas Berry (Victoria University of Wellington), Alex Simpson (Victoria University of Wellington), and Matt Visser (Victoria University of Wellington)
Unit-lapse versions of the Kerr spacetime
29 pages
null
10.1088/1361-6382/abd071
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Kerr spacetime is perhaps the most astrophysically important of the currently known exact solutions to the Einstein field equations. Whenever spacetimes can be put in unit-lapse form it becomes possible to identify some very straightforward timelike geodesics, (the "rain" geodesics), making the physical interpret...
[ { "created": "Sun, 9 Aug 2020 21:32:58 GMT", "version": "v1" } ]
2021-02-03
[ [ "Baines", "Joshua", "", "Victoria University of Wellington" ], [ "Berry", "Thomas", "", "Victoria University of Wellington" ], [ "Simpson", "Alex", "", "Victoria University of\n Wellington" ], [ "Visser", "Matt", "", "Victoria University...
The Kerr spacetime is perhaps the most astrophysically important of the currently known exact solutions to the Einstein field equations. Whenever spacetimes can be put in unit-lapse form it becomes possible to identify some very straightforward timelike geodesics, (the "rain" geodesics), making the physical interpretat...
2109.01871
Emanuelis Lazauskas
Emanuelis Lazauskas
Scalar Gravity and the Double Copy in the Framework of General Relativity
null
null
null
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The classical double copy relations establish correspondence between exact gravity solutions and their counterparts in biadjoint and gauge theories. In this work, we investigate a peculiar case of double copy relations arising in exact solutions of the scalar gravity equation, relating static spacetime geometry to th...
[ { "created": "Sat, 4 Sep 2021 13:57:18 GMT", "version": "v1" } ]
2021-09-07
[ [ "Lazauskas", "Emanuelis", "" ] ]
The classical double copy relations establish correspondence between exact gravity solutions and their counterparts in biadjoint and gauge theories. In this work, we investigate a peculiar case of double copy relations arising in exact solutions of the scalar gravity equation, relating static spacetime geometry to the ...
2311.17509
Carla Cederbaum
Carla Cederbaum and Sophia Jahns and Olivia Vi\v{c}\'anek Mart\'inez
On equipotential photon surfaces in (electro-)static spacetimes of arbitrary dimension
66 pages, 14 figures. Comments very welcome!
null
null
null
gr-qc math.DG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study timelike, totally umbilic hypersurfaces -- called photon surfaces -- in $n+1$-dimensional static, asymptotically flat spacetimes, for $n+1\geq4$. First, we give a complete characterization of photon surfaces in a class of spherically symmetric spacetimes containing the (exterior) subextremal Reissner--Nordst...
[ { "created": "Wed, 29 Nov 2023 10:33:44 GMT", "version": "v1" } ]
2023-11-30
[ [ "Cederbaum", "Carla", "" ], [ "Jahns", "Sophia", "" ], [ "Martínez", "Olivia Vičánek", "" ] ]
We study timelike, totally umbilic hypersurfaces -- called photon surfaces -- in $n+1$-dimensional static, asymptotically flat spacetimes, for $n+1\geq4$. First, we give a complete characterization of photon surfaces in a class of spherically symmetric spacetimes containing the (exterior) subextremal Reissner--Nordstr\...
1006.1122
Israel Quiros
Ricardo Garc\'ia-Salcedo, Tame Gonzalez, Claudia Moreno, Israel Quiros
Randall-Sundrum brane cosmology: modification of late-time cosmic dynamics by exotic matter
Latex, 12 pages, 9 eps figures. Title changed, discussion improved. Version that matches the one published in CQG
Class.Quant.Grav.28:105017,2011
10.1088/0264-9381/28/10/105017
null
gr-qc astro-ph.CO hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we show, through the study of concrete examples, that, depending on the cosmic dynamics of the energy density of matter degrees of freedom living in the brane, Randall-Sundrum (RS) brane effects can be important not only at short distances (UV regime), but also at large cosmological scales (IR regime). ...
[ { "created": "Sun, 6 Jun 2010 17:25:24 GMT", "version": "v1" }, { "created": "Wed, 9 Jun 2010 21:08:44 GMT", "version": "v2" }, { "created": "Mon, 20 Sep 2010 15:38:44 GMT", "version": "v3" }, { "created": "Thu, 18 Aug 2011 16:10:34 GMT", "version": "v4" } ]
2011-08-19
[ [ "García-Salcedo", "Ricardo", "" ], [ "Gonzalez", "Tame", "" ], [ "Moreno", "Claudia", "" ], [ "Quiros", "Israel", "" ] ]
In this paper we show, through the study of concrete examples, that, depending on the cosmic dynamics of the energy density of matter degrees of freedom living in the brane, Randall-Sundrum (RS) brane effects can be important not only at short distances (UV regime), but also at large cosmological scales (IR regime). Ou...
gr-qc/0412137
Deborah A. Konkowski
D.A. Konkowski and T.M. Helliwell
Mining metrics for buried treasure
16 pages, no figures, minor grammatical changes, submitted to Proceedings of the Malcolm@60 Conference (London, July 2004)
Gen.Rel.Grav. 38 (2006) 1069-1082
10.1007/s10714-006-0289-y
null
gr-qc
null
The same but different: That might describe two metrics. On the surface CLASSI may show two metrics are locally equivalent, but buried beneath one may be a wealth of further structure. This was beautifully described in a paper by M.A.H. MacCallum in 1998. Here I will illustrate the effect with two flat metrics -- one...
[ { "created": "Thu, 30 Dec 2004 18:26:49 GMT", "version": "v1" }, { "created": "Fri, 7 Jan 2005 00:12:39 GMT", "version": "v2" } ]
2009-11-10
[ [ "Konkowski", "D. A.", "" ], [ "Helliwell", "T. M.", "" ] ]
The same but different: That might describe two metrics. On the surface CLASSI may show two metrics are locally equivalent, but buried beneath one may be a wealth of further structure. This was beautifully described in a paper by M.A.H. MacCallum in 1998. Here I will illustrate the effect with two flat metrics -- one d...
1601.01735
Koray D\"uzta\c{s}
Koray D\"uzta\c{s}
Coulomb fields as perturbations of type D vacuum space-times
More detailed than the published version
Eur. Phys. J. Plus (2017) 132:406
10.1140/epjp/i2017-11710-7
null
gr-qc math-ph math.MP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider a test, non-null electromagnetic field special in the sense that the principal null directions of the field lie along the two repeated principal null directions of the type D vacuum background. We prove that the special non-null field is a valid solution of the Maxwell equations on a type D background. Th...
[ { "created": "Fri, 8 Jan 2016 00:55:12 GMT", "version": "v1" }, { "created": "Sun, 18 Sep 2016 21:58:45 GMT", "version": "v2" }, { "created": "Thu, 12 Oct 2017 08:54:29 GMT", "version": "v3" } ]
2017-10-13
[ [ "Düztaş", "Koray", "" ] ]
We consider a test, non-null electromagnetic field special in the sense that the principal null directions of the field lie along the two repeated principal null directions of the type D vacuum background. We prove that the special non-null field is a valid solution of the Maxwell equations on a type D background. This...
gr-qc/0607107
Z. Turakulov Ya.
Z. Y. Turakulov, A. T. Muminov
Motion of a vector particle in a curved space-time. III. Development of techniques of calculation
9 pages, no figures
Mod.Phys.Lett.A21:1981-1990,2006
10.1142/S0217732306021293
null
gr-qc
null
The studies of influence of spin on a photon's motion in a Schwartzschild spacetime is continued. In the previous paper [13] the first order correction to the geodesic motion is found for the first half of the photon world line. The system of equations for the first order correction to the geodesic motion is reduced ...
[ { "created": "Mon, 24 Jul 2006 13:12:55 GMT", "version": "v1" } ]
2010-11-11
[ [ "Turakulov", "Z. Y.", "" ], [ "Muminov", "A. T.", "" ] ]
The studies of influence of spin on a photon's motion in a Schwartzschild spacetime is continued. In the previous paper [13] the first order correction to the geodesic motion is found for the first half of the photon world line. The system of equations for the first order correction to the geodesic motion is reduced to...
2112.01536
Muhammad Sharif
M. Sharif and Sulaman Shaukat
Greybody Factor for a Rotating Bardeen Black Hole by Perfect Fluid Dark Matter
21 pages, 6 figures
Annals Phys. 436(2022)168673
10.1016/j.aop.2021.168673
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, the greybody factor is studied analytically for a rotating regular Bardeen black hole surrounded by perfect fluid dark matter. Firstly, we examine the behavior of effective potential by using the radial equation of motion developed from the Klein-Gordon equation. We then consider tortoise coordinate to...
[ { "created": "Thu, 2 Dec 2021 05:13:13 GMT", "version": "v1" } ]
2022-01-05
[ [ "Sharif", "M.", "" ], [ "Shaukat", "Sulaman", "" ] ]
In this paper, the greybody factor is studied analytically for a rotating regular Bardeen black hole surrounded by perfect fluid dark matter. Firstly, we examine the behavior of effective potential by using the radial equation of motion developed from the Klein-Gordon equation. We then consider tortoise coordinate to c...
2106.07981
Chen Songbai
Zelin Zhang, Songbai Chen, Xin Qin, Jiliang Jing
Polarized image of a Schwarzschild black hole with a thin accretion disk as photon couples to Weyl tensor
15 pages, 11 figures, the accepted version for publication in EPJC
Eur. Phys. J. C (2021) 81:991
10.1140/epjc/s10052-021-09786-2
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We have studied polarized image of a Schwarzschild black hole with an equatorial thin accretion disk as photon couples to Weyl tensor. The birefringence of photon originating from the coupling affect the black hole shadow, the thin disk pattern and its luminosity distribution. We also analyze the observed polarized i...
[ { "created": "Tue, 15 Jun 2021 08:58:09 GMT", "version": "v1" }, { "created": "Wed, 10 Nov 2021 08:56:55 GMT", "version": "v2" } ]
2021-11-15
[ [ "Zhang", "Zelin", "" ], [ "Chen", "Songbai", "" ], [ "Qin", "Xin", "" ], [ "Jing", "Jiliang", "" ] ]
We have studied polarized image of a Schwarzschild black hole with an equatorial thin accretion disk as photon couples to Weyl tensor. The birefringence of photon originating from the coupling affect the black hole shadow, the thin disk pattern and its luminosity distribution. We also analyze the observed polarized int...
2011.06930
Mohd Shahalam
M. Shahalam, Shynaray Myrzakul
Dynamics of nonminimally coupled scalar field models with generic potentials in FLRW background
13 pages, 5 figures. arXiv admin note: text overlap with arXiv:1905.06856
Gen Relativ Gravit 53, 45 (2021)
10.1007/s10714-021-02796-1
null
gr-qc
http://creativecommons.org/licenses/by/4.0/
We study the phase space analysis of a nonminimally coupled scalar field model with different potentials such as KKLT, Higgs, inverse and inverse square. Our investigation brings new asymptotic regimes, and obtains stable de-Sitter solution. In case of KKLT, we do not find stable de-Sitter solution whereas Higgs mode...
[ { "created": "Thu, 12 Nov 2020 02:50:03 GMT", "version": "v1" } ]
2021-04-27
[ [ "Shahalam", "M.", "" ], [ "Myrzakul", "Shynaray", "" ] ]
We study the phase space analysis of a nonminimally coupled scalar field model with different potentials such as KKLT, Higgs, inverse and inverse square. Our investigation brings new asymptotic regimes, and obtains stable de-Sitter solution. In case of KKLT, we do not find stable de-Sitter solution whereas Higgs model ...
gr-qc/0209060
Sergi R. Hildebrandt
Sergi R. Hildebrandt
A physical application of Kerr-Schild groups
18 pages
Gen. Rel. Grav., vol. 34 (2002) 159--174
10.1023/A:1015380109397
null
gr-qc
null
The present work deals with the search of useful physical applications of some generalized groups of metric transformations. We put forward different proposals and focus our attention on the implementation of one of them. Particularly, the results show how one can control very efficiently the kind of spacetimes relat...
[ { "created": "Wed, 18 Sep 2002 17:49:57 GMT", "version": "v1" } ]
2021-10-20
[ [ "Hildebrandt", "Sergi R.", "" ] ]
The present work deals with the search of useful physical applications of some generalized groups of metric transformations. We put forward different proposals and focus our attention on the implementation of one of them. Particularly, the results show how one can control very efficiently the kind of spacetimes related...
gr-qc/0608107
Dr. Anirudh Pradhan
Anirudh Pradhan, Ajay Kumar Singh and Saeed Otarod
FRW Universe with Variable $G$ and $\Lambda$-Terms
15 pages, 8 figures
Rom.J.Phys.52:445-458,2007
null
null
gr-qc
null
A new class of exact solutions of Einstein's field equations with a perfect fluid source, variable gravitational coupling $G$ and cosmological term $\Lambda$ for FRW spacetime is obtained by considering variable deceleration parameter models for the universe. The nature of the variables $G(t)$, $\Lambda(t)$ and the e...
[ { "created": "Wed, 23 Aug 2006 13:23:11 GMT", "version": "v1" } ]
2008-11-26
[ [ "Pradhan", "Anirudh", "" ], [ "Singh", "Ajay Kumar", "" ], [ "Otarod", "Saeed", "" ] ]
A new class of exact solutions of Einstein's field equations with a perfect fluid source, variable gravitational coupling $G$ and cosmological term $\Lambda$ for FRW spacetime is obtained by considering variable deceleration parameter models for the universe. The nature of the variables $G(t)$, $\Lambda(t)$ and the ene...
1612.04551
Edward Wilson-Ewing
Edward Wilson-Ewing
Testing loop quantum cosmology
20 pages. Invited review for special edition "Testing quantum gravity with cosmology" of Comptes Rendus Physique
Comptes Rendus Physique 18 (2017) 207-225
10.1016/j.crhy.2017.02.004
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Loop quantum cosmology predicts that quantum gravity effects resolve the big-bang singularity and replace it by a cosmic bounce. Furthermore, loop quantum cosmology can also modify the form of primordial cosmological perturbations, for example by reducing power at large scales in inflationary models or by suppressing...
[ { "created": "Wed, 14 Dec 2016 09:26:31 GMT", "version": "v1" }, { "created": "Tue, 28 Feb 2017 13:56:50 GMT", "version": "v2" } ]
2017-06-28
[ [ "Wilson-Ewing", "Edward", "" ] ]
Loop quantum cosmology predicts that quantum gravity effects resolve the big-bang singularity and replace it by a cosmic bounce. Furthermore, loop quantum cosmology can also modify the form of primordial cosmological perturbations, for example by reducing power at large scales in inflationary models or by suppressing t...
2401.11109
Tingqi Cai
Tingqi Cai and Yi Wang
A Topological Drive for Spacetime Travel
null
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a toy metric of spacetime travel from topological change. A bubble-like baby universe is detached and re-attached from our universe. Depending on where the bubble is re-attached, matter may travel superluminally or backwards-in-time through the bubble. Quasiregular singularities are formed at the detachmen...
[ { "created": "Sat, 20 Jan 2024 04:10:52 GMT", "version": "v1" }, { "created": "Fri, 14 Jun 2024 05:25:33 GMT", "version": "v2" } ]
2024-06-17
[ [ "Cai", "Tingqi", "" ], [ "Wang", "Yi", "" ] ]
We present a toy metric of spacetime travel from topological change. A bubble-like baby universe is detached and re-attached from our universe. Depending on where the bubble is re-attached, matter may travel superluminally or backwards-in-time through the bubble. Quasiregular singularities are formed at the detachment ...
1504.01065
Jan Ambjorn
J. Ambjorn, A. Goerlich, J. Jurkiewicz and R. Loll
Wilson loops in CDT quantum gravity
null
Phys. Rev. D 92, 024013 (2015)
10.1103/PhysRevD.92.024013
null
gr-qc hep-lat hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
By explicit construction, we show that one can in a simple way introduce and measure gravitational holonomies and Wilson loops in lattice formulations of nonperturbative quantum gravity based on (Causal) Dynamical Triangulations. We use this set-up to investigate a class of Wilson line observables associated with the...
[ { "created": "Sat, 4 Apr 2015 22:52:26 GMT", "version": "v1" } ]
2015-07-15
[ [ "Ambjorn", "J.", "" ], [ "Goerlich", "A.", "" ], [ "Jurkiewicz", "J.", "" ], [ "Loll", "R.", "" ] ]
By explicit construction, we show that one can in a simple way introduce and measure gravitational holonomies and Wilson loops in lattice formulations of nonperturbative quantum gravity based on (Causal) Dynamical Triangulations. We use this set-up to investigate a class of Wilson line observables associated with the w...
2011.14916
Anisur Rahaman
Sohan Kumar Jha, Anisur Rahaman
Bumblebee gravity with a Kerr-Sen-like solution and its Shadow
14 pages latex, 23 figures
Eur.Phys.J. C81 (2021) no.4, 345
10.1140/epjc/s10052-021-09132-6
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Lorentz-Violating (LV) scenario gets involved through a bumblebee field vector field $B_\mu$. A spontaneous symmetry breaking allows the field to acquires a vacuum expectation value that generates LV into the system. A Kerr-Sen-like solution has been found out starting from the generalized form of a radiating station...
[ { "created": "Fri, 27 Nov 2020 12:50:38 GMT", "version": "v1" } ]
2021-05-11
[ [ "Jha", "Sohan Kumar", "" ], [ "Rahaman", "Anisur", "" ] ]
Lorentz-Violating (LV) scenario gets involved through a bumblebee field vector field $B_\mu$. A spontaneous symmetry breaking allows the field to acquires a vacuum expectation value that generates LV into the system. A Kerr-Sen-like solution has been found out starting from the generalized form of a radiating stationer...
2103.06100
Jan Steinhoff
Jan Steinhoff, Tanja Hinderer, Tim Dietrich, Francois Foucart
Spin effects on neutron star fundamental-mode dynamical tides: phenomenology and comparison to numerical simulations
24 pages. v2: updated references and git link
Phys. Rev. Research 3, 033129 (2021)
10.1103/PhysRevResearch.3.033129
null
gr-qc astro-ph.HE astro-ph.SR hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Gravitational waves from neutron star binary inspirals contain information on strongly-interacting matter in unexplored, extreme regimes. Extracting this requires robust theoretical models of the signatures of matter in the gravitational-wave signals due to spin and tidal effects. In fact, spins can have a significan...
[ { "created": "Wed, 10 Mar 2021 14:55:27 GMT", "version": "v1" }, { "created": "Fri, 26 Mar 2021 12:28:13 GMT", "version": "v2" } ]
2021-08-18
[ [ "Steinhoff", "Jan", "" ], [ "Hinderer", "Tanja", "" ], [ "Dietrich", "Tim", "" ], [ "Foucart", "Francois", "" ] ]
Gravitational waves from neutron star binary inspirals contain information on strongly-interacting matter in unexplored, extreme regimes. Extracting this requires robust theoretical models of the signatures of matter in the gravitational-wave signals due to spin and tidal effects. In fact, spins can have a significant ...
1908.11265
Burin Gumjudpai
Chonticha Kritpetch (IF Naresuan), Jarunee Sanongkhun (IF Naresuan), Pichet Vanichchapongjaroen (IF Naresuan) and Burin Gumjudpai (IF Naresuan)
Non-linear Schr\"{o}dinger-type formulation of scalar field cosmology: two barotropic fluids and exact solutions
11 pages, 2 figures
Modern Physics Letters A, Vol. 35, No. 19, 2050157 (2020)
10.1142/S0217732320501576
null
gr-qc astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Time-independent non-linear Schr\"{o}dinger-type (NLS) formulation of FRW cosmology with canonical scalar field are considered in case of two barotropic fluids. We derived Friedmann formulation variables in terms of NLS variables. Seven exact solutions found by D'Ambroise \cite{DAmbroise:2010dgl} and one new found so...
[ { "created": "Thu, 29 Aug 2019 14:43:22 GMT", "version": "v1" }, { "created": "Tue, 10 Mar 2020 18:00:25 GMT", "version": "v2" } ]
2021-07-19
[ [ "Kritpetch", "Chonticha", "", "IF Naresuan" ], [ "Sanongkhun", "Jarunee", "", "IF Naresuan" ], [ "Vanichchapongjaroen", "Pichet", "", "IF Naresuan" ], [ "Gumjudpai", "Burin", "", "IF Naresuan" ] ]
Time-independent non-linear Schr\"{o}dinger-type (NLS) formulation of FRW cosmology with canonical scalar field are considered in case of two barotropic fluids. We derived Friedmann formulation variables in terms of NLS variables. Seven exact solutions found by D'Ambroise \cite{DAmbroise:2010dgl} and one new found solu...
0803.3064
Roberto Chan
R. Chan, M.F.A. da Silva, J.F. Villas da Rocha
Star Models with Dark Energy
20 pages, 1 figure, references and some comments added, typos corrected, in press GRG
Gen.Rel.Grav.41:1835-1851,2009
10.1007/s10714-008-0755-9
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We have constructed star models consisting of four parts: (i) a homogeneous inner core with anisotropic pressure (ii) an infinitesimal thin shell separating the core and the envelope; (iii) an envelope of inhomogeneous density and isotropic pressure; (iv) an infinitesimal thin shell matching the envelope boundary and...
[ { "created": "Thu, 20 Mar 2008 19:54:02 GMT", "version": "v1" }, { "created": "Tue, 30 Dec 2008 17:01:22 GMT", "version": "v2" } ]
2012-10-25
[ [ "Chan", "R.", "" ], [ "da Silva", "M. F. A.", "" ], [ "da Rocha", "J. F. Villas", "" ] ]
We have constructed star models consisting of four parts: (i) a homogeneous inner core with anisotropic pressure (ii) an infinitesimal thin shell separating the core and the envelope; (iii) an envelope of inhomogeneous density and isotropic pressure; (iv) an infinitesimal thin shell matching the envelope boundary and t...
gr-qc/9806083
null
Vladimir S. Mashkevich (Institute of Physics, Kiev)
Quantum Fields in Curved Spacetime: Quantum-Gravitational Nonlocality and Conservation of Particle Numbers
17 pages, no figures, LATEX 2.09
null
null
null
gr-qc hep-th
null
We argue that the conventional quantum field theory in curved spacetime has a grave drawback: The canonical commutation relations for quantum fields and conjugate momenta do not hold. Thus the conventional theory should be denounced and the related results revised. A Hamiltonian version of the canonical formalism for...
[ { "created": "Sat, 20 Jun 1998 13:46:29 GMT", "version": "v1" } ]
2007-05-23
[ [ "Mashkevich", "Vladimir S.", "", "Institute of Physics, Kiev" ] ]
We argue that the conventional quantum field theory in curved spacetime has a grave drawback: The canonical commutation relations for quantum fields and conjugate momenta do not hold. Thus the conventional theory should be denounced and the related results revised. A Hamiltonian version of the canonical formalism for a...
0811.1926
Andrew J. S. Hamilton
Andrew J. S. Hamilton (JILA), Pedro P. Avelino (Porto)
The physics of the relativistic counter-streaming instability that drives mass inflation inside black holes
11 eps figures. 2nd version has minor revisions. 3rd version is reformatted, has expanded abstract, and some additional minor revisions. 4th version as accepted for publication in Physics Reports
Phys.Rept.495:1-32, 2010
10.1016/j.physrep.2010.06.002
null
gr-qc astro-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
If you fall into a real astronomical black hole (choosing a supermassive black hole, to make sure that the tidal forces don't get you first), then you will probably meet your fate not at a central singularity, but rather in the exponentially growing, relativistic counter-streaming instability at the inner horizon fir...
[ { "created": "Wed, 12 Nov 2008 16:00:57 GMT", "version": "v1" }, { "created": "Mon, 8 Dec 2008 21:40:30 GMT", "version": "v2" }, { "created": "Mon, 9 Mar 2009 17:32:09 GMT", "version": "v3" }, { "created": "Tue, 15 Jun 2010 17:36:50 GMT", "version": "v4" } ]
2015-03-13
[ [ "Hamilton", "Andrew J. S.", "", "JILA" ], [ "Avelino", "Pedro P.", "", "Porto" ] ]
If you fall into a real astronomical black hole (choosing a supermassive black hole, to make sure that the tidal forces don't get you first), then you will probably meet your fate not at a central singularity, but rather in the exponentially growing, relativistic counter-streaming instability at the inner horizon first...
1810.10504
Khalid Saifullah
Rehana Rahim and Khalid Saifullah
Charging the Johannsen-Psaltis spacetime
Matches the published version
Annals of Physics 405 (2019) 220
10.1016/j.aop.2019.03.007
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we develop the charged version of the spacetime proposed by Johannsen and Psaltis. Rotation is introduced in the deformed Reissner-Nordstr\"om spacetime by complex coordinate transformation. The event horizon and Killing horizon are studied. Killing horizons are represented graphically also. The analysi...
[ { "created": "Wed, 24 Oct 2018 17:23:38 GMT", "version": "v1" }, { "created": "Thu, 18 Apr 2019 18:32:36 GMT", "version": "v2" } ]
2019-04-22
[ [ "Rahim", "Rehana", "" ], [ "Saifullah", "Khalid", "" ] ]
In this paper we develop the charged version of the spacetime proposed by Johannsen and Psaltis. Rotation is introduced in the deformed Reissner-Nordstr\"om spacetime by complex coordinate transformation. The event horizon and Killing horizon are studied. Killing horizons are represented graphically also. The analysis ...
1207.6348
Simone Speziale
Simone Speziale and Wolfgang M. Wieland
The twistorial structure of loop-gravity transition amplitudes
40 pages, 3 figures. v2: minor improvements, references added
null
10.1103/PhysRevD.86.124023
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The spin foam formalism provides transition amplitudes for loop quantum gravity. Important aspects of the dynamics are understood, but many open questions are pressing on. In this paper we address some of them using a twistorial description, which brings new light on both classical and quantum aspects of the theory. ...
[ { "created": "Thu, 26 Jul 2012 17:48:07 GMT", "version": "v1" }, { "created": "Thu, 27 Sep 2012 10:31:07 GMT", "version": "v2" } ]
2015-06-05
[ [ "Speziale", "Simone", "" ], [ "Wieland", "Wolfgang M.", "" ] ]
The spin foam formalism provides transition amplitudes for loop quantum gravity. Important aspects of the dynamics are understood, but many open questions are pressing on. In this paper we address some of them using a twistorial description, which brings new light on both classical and quantum aspects of the theory. At...
2002.02695
Francisco Pedro
Michele Cicoli, Giuseppe Dibitetto, Francisco G. Pedro
New accelerating solutions in late-time cosmology
null
Phys. Rev. D 101, 103524 (2020)
10.1103/PhysRevD.101.103524
null
gr-qc astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Dark energy models can be seen as dynamical systems. In this paper we show that multi-field models with a curved field space give rise to new critical points and we analyse their stability. These are new accelerating solutions in late-time cosmology which exist even for steep potentials. This opens up the possibility...
[ { "created": "Fri, 7 Feb 2020 10:06:06 GMT", "version": "v1" } ]
2020-05-27
[ [ "Cicoli", "Michele", "" ], [ "Dibitetto", "Giuseppe", "" ], [ "Pedro", "Francisco G.", "" ] ]
Dark energy models can be seen as dynamical systems. In this paper we show that multi-field models with a curved field space give rise to new critical points and we analyse their stability. These are new accelerating solutions in late-time cosmology which exist even for steep potentials. This opens up the possibility t...
gr-qc/9909063
Jorge Pullin
C. Di Bartolo, R. Gambini, J. Griego, J. Pullin
Consistent canonical quantization of general relativity in the space of Vassiliev knot invariants
4 pages, RevTex, one figure
Phys.Rev.Lett.84:2314-2317,2000
10.1103/PhysRevLett.84.2314
CGPG-99-9-5
gr-qc hep-th
null
We present a quantization of the Hamiltonian and diffeomorphism constraint of canonical quantum gravity in the spin network representation. The novelty consists in considering a space of wavefunctions based on the Vassiliev knot invariants. The constraints are finite, well defined, and reproduce at the level of quant...
[ { "created": "Tue, 21 Sep 1999 08:24:33 GMT", "version": "v1" } ]
2014-11-17
[ [ "Di Bartolo", "C.", "" ], [ "Gambini", "R.", "" ], [ "Griego", "J.", "" ], [ "Pullin", "J.", "" ] ]
We present a quantization of the Hamiltonian and diffeomorphism constraint of canonical quantum gravity in the spin network representation. The novelty consists in considering a space of wavefunctions based on the Vassiliev knot invariants. The constraints are finite, well defined, and reproduce at the level of quantum...
1407.1936
Manuel Malaver D
Manuel Malaver
Quark star model with charge distributions
Relativistic Objects; Electric Field; Gravitational Potential; Adjustable Parameter; Einstein-Maxwell System; Charge Density
Open Science Journal of Modern Physics,1(1),pp.6-11,2014
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we studied the behavior of relativistic objects with anisotropic matter distribution inthe presence of an electric field considering a gravitational potential Z(x) of Thirukkanesh and Ragel (2013) which depends on an adjustable parameter n. The equation of state presents a quadratic relation between th...
[ { "created": "Tue, 8 Jul 2014 03:00:13 GMT", "version": "v1" } ]
2014-07-09
[ [ "Malaver", "Manuel", "" ] ]
In this paper, we studied the behavior of relativistic objects with anisotropic matter distribution inthe presence of an electric field considering a gravitational potential Z(x) of Thirukkanesh and Ragel (2013) which depends on an adjustable parameter n. The equation of state presents a quadratic relation between the ...
1610.05282
Jose Luis Bl\'azquez-Salcedo
Jose Luis Bl\'azquez-Salcedo, Jutta Kunz, Francisco Navarro-L\'erida, Eugen Radu
Charged rotating black holes in Einstein--Maxwell--Chern-Simons theory with a negative cosmological constant
30 pages, 17 figures; added references; replaced to match published version in PRD
Phys. Rev. D 95, 064018 (2017)
10.1103/PhysRevD.95.064018
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider rotating black hole solutions in five-dimensional Einstein-Maxwell-Chern-Simons theory with a negative cosmological constant and a generic value of the Chern-Simons coupling constant $\lambda$. Using both analytical and numerical techniques, we focus on cohomogeneity-1 configurations, with two equal-magni...
[ { "created": "Mon, 17 Oct 2016 19:29:36 GMT", "version": "v1" }, { "created": "Tue, 25 Oct 2016 09:45:39 GMT", "version": "v2" }, { "created": "Wed, 22 Mar 2017 09:58:11 GMT", "version": "v3" } ]
2017-03-29
[ [ "Blázquez-Salcedo", "Jose Luis", "" ], [ "Kunz", "Jutta", "" ], [ "Navarro-Lérida", "Francisco", "" ], [ "Radu", "Eugen", "" ] ]
We consider rotating black hole solutions in five-dimensional Einstein-Maxwell-Chern-Simons theory with a negative cosmological constant and a generic value of the Chern-Simons coupling constant $\lambda$. Using both analytical and numerical techniques, we focus on cohomogeneity-1 configurations, with two equal-magnitu...
gr-qc/0310041
Achamveedu Gopakumar
Gerhard Sch\"afer and Achamveedu Gopakumar
A minimal no-radiation approximation to Einstein's field equations
9 pages
Phys.Rev.D69:021501,2004
10.1103/PhysRevD.69.021501
null
gr-qc
null
An approximation to Einstein's field equations in Arnowitt-Deser-Misner (ADM) canonical formalism is presented which corresponds to the magneto-hydrodynamics (MHD) approximation in electrodynamics. It results in coupled elliptic equations which represent the maximum of elliptic-type structure of Einstein's theory and...
[ { "created": "Tue, 7 Oct 2003 16:06:14 GMT", "version": "v1" } ]
2008-11-26
[ [ "Schäfer", "Gerhard", "" ], [ "Gopakumar", "Achamveedu", "" ] ]
An approximation to Einstein's field equations in Arnowitt-Deser-Misner (ADM) canonical formalism is presented which corresponds to the magneto-hydrodynamics (MHD) approximation in electrodynamics. It results in coupled elliptic equations which represent the maximum of elliptic-type structure of Einstein's theory and n...
1204.0295
Mir Faizal
Mir Faizal
Noncommutativity and Non-anticommutativity in Perturbative Quantum Gravity
9 pages, 0 figures, accepted for publication in Mod. Phys. Lett. A
Mod. Phys. Lett. A27: 1250075, 2012
10.1142/S0217732312500757
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we will study perturbative quantum gravity on supermanifolds with both noncommutative and non-anticommutative coordinates. We shall first analyses the BRST and the anti-BRST symmetries of this theory. Then we will also analyze the effect of shifting all the fields of this theory in background field meth...
[ { "created": "Mon, 2 Apr 2012 02:28:06 GMT", "version": "v1" } ]
2015-06-04
[ [ "Faizal", "Mir", "" ] ]
In this paper we will study perturbative quantum gravity on supermanifolds with both noncommutative and non-anticommutative coordinates. We shall first analyses the BRST and the anti-BRST symmetries of this theory. Then we will also analyze the effect of shifting all the fields of this theory in background field method...
2106.08342
B\'eatrice Bonga
B\'eatrice Bonga and Huan Yang
Mimicking Kerr's multipole moments
8 pages, 3 figures; updated to match the published version (includes an extended introduction and discussion)
Phys. Rev. D, 104, 2021, 084040
10.1103/PhysRevD.104.084040
null
gr-qc hep-th
http://creativecommons.org/licenses/by/4.0/
Multipole moments carry a lot of information about the gravitational field. Nonetheless, knowing all the multipole moments of an object does not determine conclusively the nature of the object itself. In particular, the multipole moments of the Kerr spacetime are not unique. Here we construct several physically motiv...
[ { "created": "Tue, 15 Jun 2021 18:00:04 GMT", "version": "v1" }, { "created": "Wed, 13 Oct 2021 08:47:47 GMT", "version": "v2" } ]
2021-10-14
[ [ "Bonga", "Béatrice", "" ], [ "Yang", "Huan", "" ] ]
Multipole moments carry a lot of information about the gravitational field. Nonetheless, knowing all the multipole moments of an object does not determine conclusively the nature of the object itself. In particular, the multipole moments of the Kerr spacetime are not unique. Here we construct several physically motivat...
1604.05052
Jerzy Kijowski
Jerzy Kijowski
Universality of the Einstein theory of gravitation
null
null
10.1142/S0219887816400089
null
gr-qc math-ph math.MP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show that generalizations of general relativity theory, which consist in replacing the Hilbert Lagrangian $L_{Hilbert} = \frac 1{16\pi} \sqrt{|g|} R$ by a generic scalar density $L=L(g_{\mu\nu}, R^\lambda_{\mu\nu\kappa})$ depending upon the metric $g_{\mu\nu}$ and the curvature tensor $R^\lambda_{\mu\nu\kappa}$, a...
[ { "created": "Mon, 18 Apr 2016 09:18:29 GMT", "version": "v1" } ]
2016-09-21
[ [ "Kijowski", "Jerzy", "" ] ]
We show that generalizations of general relativity theory, which consist in replacing the Hilbert Lagrangian $L_{Hilbert} = \frac 1{16\pi} \sqrt{|g|} R$ by a generic scalar density $L=L(g_{\mu\nu}, R^\lambda_{\mu\nu\kappa})$ depending upon the metric $g_{\mu\nu}$ and the curvature tensor $R^\lambda_{\mu\nu\kappa}$, are...
1112.0575
Iain Brown
Iain A. Brown and Amir Hammami
Gauge Issues in Extended Gravity and f(R) Cosmology
12 pages, REVTeX4. Replaced with version accepted by JCAP. Citations added and some clarifications
JCAP 04 (2012) 002
10.1088/1475-7516/2012/04/002
null
gr-qc astro-ph.CO hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider issues related to the conformal mapping between the Einstein and Jordan frames in f(R) cosmology. We consider the impact of the conformal transformation on the gauge of a perturbed system and show that unless the system is written in a restricted set of gauges the mapping could produce an inconsistent res...
[ { "created": "Fri, 2 Dec 2011 21:01:10 GMT", "version": "v1" }, { "created": "Tue, 3 Apr 2012 11:47:31 GMT", "version": "v2" } ]
2015-06-03
[ [ "Brown", "Iain A.", "" ], [ "Hammami", "Amir", "" ] ]
We consider issues related to the conformal mapping between the Einstein and Jordan frames in f(R) cosmology. We consider the impact of the conformal transformation on the gauge of a perturbed system and show that unless the system is written in a restricted set of gauges the mapping could produce an inconsistent resul...
2003.02690
William Barker Mr
W. E. V. Barker, A. N. Lasenby, M. P. Hobson and W. J. Handley
Addressing $H_0$ tension with emergent dark radiation in unitary gravity
32 pages, 5 figures, 2 tables. Titular change. Updated ref. [85] and ref. [96]. Version to appear in Phys. Rev. D
Phys. Rev. D 102, 024048 (2020)
10.1103/PhysRevD.102.024048
null
gr-qc astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a one-parameter extension to $\Lambda$CDM, expected to strongly affect cosmological tensions. An effective dark radiation component in the early universe redshifts away as hot dark matter, then quintessence, tracking the dominant equation-of-state parameter and leaving a falsifiable torsion field in the cu...
[ { "created": "Thu, 5 Mar 2020 14:59:08 GMT", "version": "v1" }, { "created": "Thu, 12 Mar 2020 02:56:10 GMT", "version": "v2" }, { "created": "Mon, 13 Jul 2020 17:49:29 GMT", "version": "v3" } ]
2020-07-22
[ [ "Barker", "W. E. V.", "" ], [ "Lasenby", "A. N.", "" ], [ "Hobson", "M. P.", "" ], [ "Handley", "W. J.", "" ] ]
We propose a one-parameter extension to $\Lambda$CDM, expected to strongly affect cosmological tensions. An effective dark radiation component in the early universe redshifts away as hot dark matter, then quintessence, tracking the dominant equation-of-state parameter and leaving a falsifiable torsion field in the curr...
1905.09476
Martin Green
M. A. Green and J. W. Moffat
Modified Gravity (MOG) fits to observed radial acceleration of SPARC galaxies
11 pages, 11 figures
Physics of the Dark Universe 25 (2019) 100323
10.1016/j.dark.2019.100323
null
gr-qc astro-ph.GA
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The equation of motion in the generally covariant modified gravity (MOG) theory leads, for weak gravitational fields and non-relativistic motion, to a modification of Newton's gravitational acceleration law. In addition to the metric $g_{\mu\nu}$, MOG has a vector field $\phi_\mu$ that couples with gravitational stre...
[ { "created": "Tue, 21 May 2019 18:32:08 GMT", "version": "v1" } ]
2019-05-24
[ [ "Green", "M. A.", "" ], [ "Moffat", "J. W.", "" ] ]
The equation of motion in the generally covariant modified gravity (MOG) theory leads, for weak gravitational fields and non-relativistic motion, to a modification of Newton's gravitational acceleration law. In addition to the metric $g_{\mu\nu}$, MOG has a vector field $\phi_\mu$ that couples with gravitational streng...
gr-qc/9907025
Piotr Jaranowski
Piotr Jaranowski and Gerhard Sch\"afer
On bare masses in time-symmetric initial-value solutions for two black holes
LaTeX, 4 pages
Phys.Rev.D61:064008,2000
10.1103/PhysRevD.61.064008
null
gr-qc
null
The Brill-Lindquist time-symmetric initial-value solution for two uncharged black holes is rederived using the Hamiltonian constraint equation with Dirac delta distributions as a source for the binary black-hole field. The bare masses of the Brill-Lindquist black holes are introduced in a way which is applied, after ...
[ { "created": "Tue, 6 Jul 1999 17:43:14 GMT", "version": "v1" } ]
2008-11-26
[ [ "Jaranowski", "Piotr", "" ], [ "Schäfer", "Gerhard", "" ] ]
The Brill-Lindquist time-symmetric initial-value solution for two uncharged black holes is rederived using the Hamiltonian constraint equation with Dirac delta distributions as a source for the binary black-hole field. The bare masses of the Brill-Lindquist black holes are introduced in a way which is applied, after st...
gr-qc/9611001
Gary Gibbons
G W Gibbons
Master Equations and Majorana Spinors
16 pages plain TEX, no figures to appear in the special issue of Classical and Quantum Gravity to celebrate the 64th birthday of A Trautmann
Class.Quant.Grav.14:A155-A164,1997
10.1088/0264-9381/14/1A/013
null
gr-qc hep-th
null
I describe how the states of a discrete automata with p sites, each of which may be off or on, can be represented as Majorana spinors associated to a spacetime with signature (p,p). Some ideas about the quantization of such systems are discussed and the relationship to some unconventional formulations and generalizat...
[ { "created": "Fri, 1 Nov 1996 15:38:10 GMT", "version": "v1" } ]
2010-04-06
[ [ "Gibbons", "G W", "" ] ]
I describe how the states of a discrete automata with p sites, each of which may be off or on, can be represented as Majorana spinors associated to a spacetime with signature (p,p). Some ideas about the quantization of such systems are discussed and the relationship to some unconventional formulations and generalizatio...
gr-qc/9906027
null
Parthasarathi Majumdar and Soumitra SenGupta
Parity Violating Gravitational Coupling Of Electromagnetic Fields
7 Pages, Latex . no figures, Replaced with Revtex version, many references added and typos corrected
Class.Quant.Grav.16:L89-L94,1999
10.1088/0264-9381/16/12/102
null
gr-qc
null
A manifestly gauge invariant formulation of the coupling of the Maxwell theory with an Einstein Cartan geometry is given, where the space time torsion originates from a massless Kalb-Ramond field augmented by suitable U(1) Chern Simons terms.We focus on the situation where the torsion violates parity, and relate it t...
[ { "created": "Mon, 7 Jun 1999 12:20:58 GMT", "version": "v1" }, { "created": "Sat, 10 Jul 1999 11:51:55 GMT", "version": "v2" } ]
2010-04-06
[ [ "Majumdar", "Parthasarathi", "" ], [ "SenGupta", "Soumitra", "" ] ]
A manifestly gauge invariant formulation of the coupling of the Maxwell theory with an Einstein Cartan geometry is given, where the space time torsion originates from a massless Kalb-Ramond field augmented by suitable U(1) Chern Simons terms.We focus on the situation where the torsion violates parity, and relate it to ...
gr-qc/9712031
Mikel Susperregi
Mikel Susperregi (QMW, Univ. of London)
How typical is General Relativity in Brans-Dicke chaotic inflation?
Submitted to Phys Rev D. 24 pages, 3 figures. LaTeX, figures in ps format
null
null
null
gr-qc
null
General Relativity is recovered from Brans-Dicke gravity in the limit of large $\omega$. In this article we investigate theories of Brans-Dicke gravity with chaotic inflation, allowing for either a constant or variable value of $\omega$, known as extended and hyperextended inflation respectively. The main focus of th...
[ { "created": "Fri, 5 Dec 1997 15:36:18 GMT", "version": "v1" } ]
2007-05-23
[ [ "Susperregi", "Mikel", "", "QMW, Univ. of London" ] ]
General Relativity is recovered from Brans-Dicke gravity in the limit of large $\omega$. In this article we investigate theories of Brans-Dicke gravity with chaotic inflation, allowing for either a constant or variable value of $\omega$, known as extended and hyperextended inflation respectively. The main focus of the ...
gr-qc/0211038
Bijaya Kumar Sahoo
B.K.Sahoo and L.P.Singh
Cosmic Evolution in Generalised Brans-Dicke Theory
12 pages, no figures
Mod.Phys.Lett. A18 (2003) 2725-2734
10.1142/S0217732303012106
null
gr-qc
null
We have studied the Generalised Brans-Dicke theory and obtained exact solutions of a(t),phi(t),and omega(t) for different epochs of the cosmic evolution .We discuss how inflation,decceleration,cosmic acceleration can result from this solution.The time variation of G(t) is also examined.
[ { "created": "Tue, 12 Nov 2002 06:10:51 GMT", "version": "v1" } ]
2009-11-07
[ [ "Sahoo", "B. K.", "" ], [ "Singh", "L. P.", "" ] ]
We have studied the Generalised Brans-Dicke theory and obtained exact solutions of a(t),phi(t),and omega(t) for different epochs of the cosmic evolution .We discuss how inflation,decceleration,cosmic acceleration can result from this solution.The time variation of G(t) is also examined.
1510.07836
Oleg Evnin
Ben Craps and Oleg Evnin
AdS (in)stability: an analytic approach
14 pages, based in part on an invited talk at the Leuven workshop on The String Theory Universe, September 7-11, 2015; v2: minor clarifications and references added
Fortschr. Phys. 64 (2016) 336
10.1002/prop.201500067
null
gr-qc hep-th nlin.CD
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We briefly review the topic of AdS (in)stability, mainly focusing on a recently introduced analytic approach and its interplay with numerical results.
[ { "created": "Tue, 27 Oct 2015 10:03:30 GMT", "version": "v1" }, { "created": "Tue, 3 Nov 2015 02:32:14 GMT", "version": "v2" } ]
2016-04-19
[ [ "Craps", "Ben", "" ], [ "Evnin", "Oleg", "" ] ]
We briefly review the topic of AdS (in)stability, mainly focusing on a recently introduced analytic approach and its interplay with numerical results.
1405.2569
Mustapha Azreg-A\"inou
Mustapha Azreg-A\"inou
Generating rotating regular black hole solutions without complexification
12 pages, 4 figures. This is the extended version of the previously entitled "On `Rotating regular black hole solution': Generating the physical solution in Boyer-Lindquist coordinates" one. Minor corrections
Phys. Rev. D 90, 064041 (2014)
10.1103/PhysRevD.90.064041
null
gr-qc hep-th math-ph math.MP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We drop the complexification procedure from the Newman-Janis algorithm and introduce more physical arguments and symmetry properties, and we show how one can generate regular and singular rotating black hole and non-black-hole solutions in Boyer-Lindquist coordinates. We focus on generic rotating regular black holes ...
[ { "created": "Sun, 11 May 2014 18:57:18 GMT", "version": "v1" }, { "created": "Wed, 3 Sep 2014 06:16:00 GMT", "version": "v2" }, { "created": "Wed, 24 Sep 2014 06:27:31 GMT", "version": "v3" } ]
2014-09-25
[ [ "Azreg-Aïnou", "Mustapha", "" ] ]
We drop the complexification procedure from the Newman-Janis algorithm and introduce more physical arguments and symmetry properties, and we show how one can generate regular and singular rotating black hole and non-black-hole solutions in Boyer-Lindquist coordinates. We focus on generic rotating regular black holes an...
gr-qc/9803015
Takeshi Chiba
Takeshi Chiba, Kei-ichi Maeda, Ken-ichi Nakao, Taro Tsukamoto
Two Boosted Black Holes in Asymptotically de Sitter Space-Time - Relation between Mass and Apparent Horizon Formation -
15 pages, accepted for publication in PRD
Phys.Rev. D57 (1998) 6119-6126
10.1103/PhysRevD.57.6119
YITP-98-7, WU-AP/70/98, KUNS-1490
gr-qc
null
We study the apparent horizon for two boosted black holes in the asymptotically de Sitter space-time by solving the initial data on a space with punctures. We show that the apparent horizon enclosing both black holes is not formed if the conserved mass of the system (Abbott-Deser mass) is larger than a critical mass....
[ { "created": "Wed, 4 Mar 1998 05:24:17 GMT", "version": "v1" } ]
2019-08-17
[ [ "Chiba", "Takeshi", "" ], [ "Maeda", "Kei-ichi", "" ], [ "Nakao", "Ken-ichi", "" ], [ "Tsukamoto", "Taro", "" ] ]
We study the apparent horizon for two boosted black holes in the asymptotically de Sitter space-time by solving the initial data on a space with punctures. We show that the apparent horizon enclosing both black holes is not formed if the conserved mass of the system (Abbott-Deser mass) is larger than a critical mass. T...
1806.10005
Dimitris Moustos
Dimitris Moustos
Asymptotic states of accelerated detectors and universality of the Unruh effect
18 pages, 2 figures, Updated to match the published version. arXiv admin note: text overlap with arXiv:1611.02477
Phys. Rev. D 98, 065006 (2018)
10.1103/PhysRevD.98.065006
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We treat an Unruh-DeWitt detector as an open quantum system and evaluate the response of a uniformly accelerated detector: (i) interacting locally with the derivatives of a massless scalar field and (ii) linearly coupled to an electromagnetic field. We find that the early-time transition rate of the detector strongly...
[ { "created": "Mon, 25 Jun 2018 16:31:02 GMT", "version": "v1" }, { "created": "Tue, 11 Sep 2018 16:41:57 GMT", "version": "v2" } ]
2018-09-17
[ [ "Moustos", "Dimitris", "" ] ]
We treat an Unruh-DeWitt detector as an open quantum system and evaluate the response of a uniformly accelerated detector: (i) interacting locally with the derivatives of a massless scalar field and (ii) linearly coupled to an electromagnetic field. We find that the early-time transition rate of the detector strongly d...
1512.05268
Ali \"Ovg\"un
Ali \"Ovg\"un and Kimet Jusufi
Massive Vector Particles Tunneling From Noncommutative Charged Black Holes and its GUP-corrected Thermodynamics
10 pages, to appear in EPJ Plus
Eur. Phys. J. Plus (2016) 131: 177
10.1140/epjp/i2016-16177-4
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we investigate the tunneling process of charged massive bosons $W^{\pm }$ (spin-1 particles) from noncommutative charged black holes such as charged RN black holes and charged BTZ black holes. By applying the WKB approximation and by using the Hamilton-Jacobi equation we derive the tunneling rate and t...
[ { "created": "Wed, 16 Dec 2015 18:17:07 GMT", "version": "v1" }, { "created": "Tue, 26 Apr 2016 13:48:07 GMT", "version": "v2" } ]
2016-05-26
[ [ "Övgün", "Ali", "" ], [ "Jusufi", "Kimet", "" ] ]
In this paper, we investigate the tunneling process of charged massive bosons $W^{\pm }$ (spin-1 particles) from noncommutative charged black holes such as charged RN black holes and charged BTZ black holes. By applying the WKB approximation and by using the Hamilton-Jacobi equation we derive the tunneling rate and the...
1406.1105
Massimo Cerdonio
Massimo Cerdonio and Carlo Rovelli
A Casimir cannot cavity fly
misprints in formulas amended; references added; english refurbished; no change in substance
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The field inside a Casimir cavity has an effective negative mass, which acts as a buoyancy force in a gravitational field. Can this render the total mass of the cavity negative, making it "float" in the vacuum ? Recent theoretical arguments indicate that this is impossible. We provide support to this conclusion discu...
[ { "created": "Wed, 4 Jun 2014 16:46:25 GMT", "version": "v1" }, { "created": "Sun, 3 Aug 2014 07:44:13 GMT", "version": "v2" }, { "created": "Sun, 8 Feb 2015 19:46:48 GMT", "version": "v3" } ]
2015-02-10
[ [ "Cerdonio", "Massimo", "" ], [ "Rovelli", "Carlo", "" ] ]
The field inside a Casimir cavity has an effective negative mass, which acts as a buoyancy force in a gravitational field. Can this render the total mass of the cavity negative, making it "float" in the vacuum ? Recent theoretical arguments indicate that this is impossible. We provide support to this conclusion discuss...
1106.5638
Khedmat Atazadeh
A. H. Ziaie, K. Atazadeh, S. M. M. Rasouli
Naked Singularity Formation In f(R) Gravity
15 pages, 4 figures, to appear in GRG
Gen Relativ Gravit 43 (2011) 2943
10.1007/s10714-011-1216-4
null
gr-qc hep-th
http://creativecommons.org/licenses/by/3.0/
We study the gravitational collapse of a star with barotropic equation of state $p=w\rho$ in the context of $f({\mathcal R})$ theories of gravity. Utilizing the metric formalism, we rewrite the field equations as those of Brans-Dicke theory with vanishing coupling parameter. By choosing the functionality of Ricci sca...
[ { "created": "Tue, 28 Jun 2011 12:15:41 GMT", "version": "v1" } ]
2015-05-28
[ [ "Ziaie", "A. H.", "" ], [ "Atazadeh", "K.", "" ], [ "Rasouli", "S. M. M.", "" ] ]
We study the gravitational collapse of a star with barotropic equation of state $p=w\rho$ in the context of $f({\mathcal R})$ theories of gravity. Utilizing the metric formalism, we rewrite the field equations as those of Brans-Dicke theory with vanishing coupling parameter. By choosing the functionality of Ricci scala...
1904.09897
Shambel Sahlu Akalu
Shambel Sahlu, Joseph Ntahompagaze, Maye Elmardi and Amare Abebe
The Chaplygin gas as a model for modified teleparallel gravity?
null
null
10.1140/epjc/s10052-019-7226-1
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper explores the possibility of treating the exotic Chaplygin-gas (CG) fluid model as some manifestation of an $f(T)$ gravitation. To this end, we use the different cosmological CG equations of state, compare them with the equation of state for the modified teleparallel gravity and reconstruct the correspondin...
[ { "created": "Mon, 22 Apr 2019 14:31:48 GMT", "version": "v1" }, { "created": "Tue, 10 Sep 2019 06:11:05 GMT", "version": "v2" } ]
2019-10-02
[ [ "Sahlu", "Shambel", "" ], [ "Ntahompagaze", "Joseph", "" ], [ "Elmardi", "Maye", "" ], [ "Abebe", "Amare", "" ] ]
This paper explores the possibility of treating the exotic Chaplygin-gas (CG) fluid model as some manifestation of an $f(T)$ gravitation. To this end, we use the different cosmological CG equations of state, compare them with the equation of state for the modified teleparallel gravity and reconstruct the corresponding ...
1309.2027
Yuan Zhang
Yuan Zhang, Sijie Gao
Testing cosmic censorship conjecture near extremal black holes with cosmological constants
15 pages, 1 figure
Int. J. Mod. Phys. D Vol. 23, No. 5 (2014) 1450044
10.1142/S0218271814500448
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It has been shown previously that an extremal Reissner-Nordstr\"om or an extremal Kerr black hole cannot be overcharged or overspun by a test particle if radiative and self-force effects are neglected. In this paper, we consider extremal charged and rotating black holes with cosmological constants. By studying the mo...
[ { "created": "Mon, 9 Sep 2013 01:50:04 GMT", "version": "v1" }, { "created": "Tue, 7 Jan 2014 12:26:04 GMT", "version": "v2" }, { "created": "Tue, 1 Apr 2014 13:21:19 GMT", "version": "v3" } ]
2014-04-02
[ [ "Zhang", "Yuan", "" ], [ "Gao", "Sijie", "" ] ]
It has been shown previously that an extremal Reissner-Nordstr\"om or an extremal Kerr black hole cannot be overcharged or overspun by a test particle if radiative and self-force effects are neglected. In this paper, we consider extremal charged and rotating black holes with cosmological constants. By studying the moti...
gr-qc/0702044
Fotini Markopoulou Kalamara
Fotini Markopoulou and Lee Smolin
Disordered locality in loop quantum gravity states
11 pages, 4 figures, revision with extended discussion of results
Class.Quant.Grav.24:3813-3824,2007
10.1088/0264-9381/24/15/003
null
gr-qc
null
We show that loop quantum gravity suffers from a potential problem with non-locality, coming from a mismatch between micro-locality, as defined by the combinatorial structures of their microscopic states, and macro-locality, defined by the metric which emerges from the low energy limit. As a result, the low energy li...
[ { "created": "Wed, 7 Feb 2007 22:30:02 GMT", "version": "v1" }, { "created": "Sat, 21 Apr 2007 14:05:46 GMT", "version": "v2" } ]
2008-11-26
[ [ "Markopoulou", "Fotini", "" ], [ "Smolin", "Lee", "" ] ]
We show that loop quantum gravity suffers from a potential problem with non-locality, coming from a mismatch between micro-locality, as defined by the combinatorial structures of their microscopic states, and macro-locality, defined by the metric which emerges from the low energy limit. As a result, the low energy limi...
gr-qc/9404037
Hans-Juergen Schmidt
Hans - J\"urgen Schmidt
Why do all the curvature invariants of a gravitational wave vanish ?
9 pages
G. Sardanashvily (Ed.) New frontiers in gravitation, Hadronic Press (1996) 337-344
null
Preprint 94/03 Uni Potsdam, Mathematik
gr-qc
null
We prove the theorem valid for (Pseudo)-Riemannian manifolds $V_n$: "Let $x \in V_n$ be a fixed point of a homothetic motion which is not an isometry then all curvature invariants vanish at $x$." and get the Corollary: "All curvature invariants of the plane wave metric $$ds \sp 2 \quad = \quad 2 \, du \, dv \, + \, a...
[ { "created": "Tue, 19 Apr 1994 10:59:30 GMT", "version": "v1" } ]
2007-05-23
[ [ "Schmidt", "Hans - Jürgen", "" ] ]
We prove the theorem valid for (Pseudo)-Riemannian manifolds $V_n$: "Let $x \in V_n$ be a fixed point of a homothetic motion which is not an isometry then all curvature invariants vanish at $x$." and get the Corollary: "All curvature invariants of the plane wave metric $$ds \sp 2 \quad = \quad 2 \, du \, dv \, + \, a\s...
1604.05168
Nikolaos Dimakis
N. Dimakis, A. Karagiorgos, Adamantia Zampeli, Andronikos Paliathanasis, T. Christodoulakis and Petros A. Terzis
General Analytic Solutions of Scalar Field Cosmology with Arbitrary Potential
24 pages, 3 figures
Phys. Rev. D 93, 123518 (2016)
10.1103/PhysRevD.93.123518
null
gr-qc math-ph math.MP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present the solution space for the case of a minimally coupled scalar field with arbitrary potential in a FLRW metric. This is made possible due to the existence of a nonlocal integral of motion corresponding to the conformal Killing field of the two-dimensional minisuperspace metric. The case for both spatially f...
[ { "created": "Mon, 18 Apr 2016 14:09:19 GMT", "version": "v1" }, { "created": "Mon, 13 Jun 2016 11:49:01 GMT", "version": "v2" } ]
2016-06-22
[ [ "Dimakis", "N.", "" ], [ "Karagiorgos", "A.", "" ], [ "Zampeli", "Adamantia", "" ], [ "Paliathanasis", "Andronikos", "" ], [ "Christodoulakis", "T.", "" ], [ "Terzis", "Petros A.", "" ] ]
We present the solution space for the case of a minimally coupled scalar field with arbitrary potential in a FLRW metric. This is made possible due to the existence of a nonlocal integral of motion corresponding to the conformal Killing field of the two-dimensional minisuperspace metric. The case for both spatially fla...
gr-qc/9710113
Paulo Rodrigues Lima Vargas Moniz
P. V. Moniz (DAMTP, University of Cambridge)
Origin of Structure in a Supersymmetric Quantum Universe
3 pages, LaTeX, requires mprocl.sty available at http://shemesh.fiz.huji.ac.il/MG8/submission.html, talk given in the Early Universe session at the MG8 Conference
Phys.Rev.D57:7071-7074,1998
10.1103/PhysRevD.57.7071
null
gr-qc astro-ph hep-th
null
In this report we advance the current repertoire of quantum cosmological models to incorporate inhomogenous field modes in a supersymmetric manner. In particular, we introduce perturbations about a supersymmetric FRW model. A quantum state of our model has properties typical of the no-boundary (Hartle--Hawking) propo...
[ { "created": "Mon, 27 Oct 1997 11:51:24 GMT", "version": "v1" } ]
2009-12-30
[ [ "Moniz", "P. V.", "", "DAMTP, University of Cambridge" ] ]
In this report we advance the current repertoire of quantum cosmological models to incorporate inhomogenous field modes in a supersymmetric manner. In particular, we introduce perturbations about a supersymmetric FRW model. A quantum state of our model has properties typical of the no-boundary (Hartle--Hawking) proposa...
2302.12296
Riccardo Della Monica
Riccardo Della Monica, Ivan de Martino, Mariafelicia de Laurentis
Response to: Comment on "Orbital precession of the S2 star in scalar-tensor-vector gravity"
4 pages, 2 figures, 1 appendix. Accepted for publication in MNRAS
null
10.1093/mnras/stad579
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The explicit derivation for the orbital precession of the S2 star in the Galactic Center in the Scalar-Tensor-Vector Gravity is discussed and compared with previous research. The two different predictions are validated by numerically integrating the geodesic equations for a test particle.
[ { "created": "Thu, 23 Feb 2023 19:23:26 GMT", "version": "v1" } ]
2023-02-27
[ [ "Della Monica", "Riccardo", "" ], [ "de Martino", "Ivan", "" ], [ "de Laurentis", "Mariafelicia", "" ] ]
The explicit derivation for the orbital precession of the S2 star in the Galactic Center in the Scalar-Tensor-Vector Gravity is discussed and compared with previous research. The two different predictions are validated by numerically integrating the geodesic equations for a test particle.
0705.1882
Shabbir Ghulam
Ghulam Shabbir
Weyl Projective Curvature Symmetry in FRW k=0 Model
7pages. submitted
null
null
null
gr-qc
null
A study of proper Weyl projective curvature collineations in FRW k=0 space-time is given using the rank of Weyl projective curvature matrix and direct integration techniques. It is shown that a very special class of the above space-time admits proper Weyl projective curvature collineation.
[ { "created": "Mon, 14 May 2007 07:56:40 GMT", "version": "v1" } ]
2007-05-23
[ [ "Shabbir", "Ghulam", "" ] ]
A study of proper Weyl projective curvature collineations in FRW k=0 space-time is given using the rank of Weyl projective curvature matrix and direct integration techniques. It is shown that a very special class of the above space-time admits proper Weyl projective curvature collineation.
2001.03768
Martin Kuchynka
Martin Kuchynka
Einstein-Yang-Mills fields immune to quantum corrections
6 pages, 0 figures
null
null
null
gr-qc hep-th math-ph math.MP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Just recently, the class of all Einstein-Maxwell fields solving simultaneously also any higher-order modification of the Eintein-Maxwell theory has been completely identified. In the present work, we argue that, in view of our recent results on nonabelian gauge fields, analogous identification can be in fact achieved...
[ { "created": "Sat, 11 Jan 2020 15:56:57 GMT", "version": "v1" } ]
2020-01-14
[ [ "Kuchynka", "Martin", "" ] ]
Just recently, the class of all Einstein-Maxwell fields solving simultaneously also any higher-order modification of the Eintein-Maxwell theory has been completely identified. In the present work, we argue that, in view of our recent results on nonabelian gauge fields, analogous identification can be in fact achieved f...
2207.05076
Jainendra Kumar Singh Dr.
Shaily, J. K. Singh, Joao R. L. Santos, M. Zeyauddin
Dynamical analysis of a hyperbolic solution in Scale-covariant theory
20 pages, 19 figures
International Journal of Modern Physics D, 2024
null
null
gr-qc
http://creativecommons.org/licenses/by/4.0/
We study an isotropic flat FLRW-model in Scale-covariant theory of gravity $ f_{\gamma \delta}(\phi) $ \cite{Canuto:1977zz} which is explained in terms of ordinary and covariant differentiation of scalar field $ \phi $. As we know the deceleration parameter is time-dependent, so we consider the deceleration parameter...
[ { "created": "Mon, 11 Jul 2022 12:17:52 GMT", "version": "v1" }, { "created": "Tue, 30 Apr 2024 03:20:17 GMT", "version": "v2" } ]
2024-05-01
[ [ "Shaily", "", "" ], [ "Singh", "J. K.", "" ], [ "Santos", "Joao R. L.", "" ], [ "Zeyauddin", "M.", "" ] ]
We study an isotropic flat FLRW-model in Scale-covariant theory of gravity $ f_{\gamma \delta}(\phi) $ \cite{Canuto:1977zz} which is explained in terms of ordinary and covariant differentiation of scalar field $ \phi $. As we know the deceleration parameter is time-dependent, so we consider the deceleration parameter $...
1909.04155
Alexander B. Balakin
Alexander B. Balakin and Dmitry E. Groshev
Magneto-electro-statics of axionically active systems: Induced field restructuring in magnetic stars
13 pages, 4 figures; replaced with the revised version published in Phys.Rev.D
Phys. Rev. D 101, 023009 (2020)
10.1103/PhysRevD.101.023009
null
gr-qc astro-ph.HE hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In the framework of Einstein-Maxwell-axion theory we consider a static field configuration in the outer zone of a magnetic star. We assume that this field configuration is formed by the following interacting quartet: a spherically symmetric gravitational field of the Reissner-Nordstr\"om type, pseudoscalar field, ass...
[ { "created": "Mon, 9 Sep 2019 21:00:10 GMT", "version": "v1" }, { "created": "Fri, 24 Jan 2020 14:23:33 GMT", "version": "v2" } ]
2020-01-27
[ [ "Balakin", "Alexander B.", "" ], [ "Groshev", "Dmitry E.", "" ] ]
In the framework of Einstein-Maxwell-axion theory we consider a static field configuration in the outer zone of a magnetic star. We assume that this field configuration is formed by the following interacting quartet: a spherically symmetric gravitational field of the Reissner-Nordstr\"om type, pseudoscalar field, assoc...
2007.12023
Bahram Mashhoon
Bahram Mashhoon
Critical Tidal Currents in General Relativity
26 pages; v2: minor improvements, invited contribution to appear in Universe; v3: two errant numerical coefficients in equation (15) corrected. These errors propagated to Section IV; hence, equations (35), (38), (40), (43), (44), (46), (47), (61) and (62) have also been corrected, main results and conclusions r...
Universe 6, 104 (2020)
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Relativistic tidal equations are formulated with respect to the rest frame of a central gravitational source and their solutions are studied. The existence of certain relativistic critical tidal currents are thereby elucidated. Specifically, observers that are spatially at rest in the exterior Kerr spacetime are cons...
[ { "created": "Thu, 23 Jul 2020 14:05:23 GMT", "version": "v1" }, { "created": "Thu, 30 Jul 2020 11:10:48 GMT", "version": "v2" }, { "created": "Sun, 11 Oct 2020 09:20:55 GMT", "version": "v3" } ]
2020-10-13
[ [ "Mashhoon", "Bahram", "" ] ]
Relativistic tidal equations are formulated with respect to the rest frame of a central gravitational source and their solutions are studied. The existence of certain relativistic critical tidal currents are thereby elucidated. Specifically, observers that are spatially at rest in the exterior Kerr spacetime are consid...
0710.2333
Kumar Virbhadra
K. S. Virbhadra and C. R. Keeton
Time delay and magnification centroid due to gravitational lensing by black holes and naked singularities
RevTex, 14 pages, 5 figures
Phys.Rev.D77:124014,2008
10.1103/PhysRevD.77.124014
null
gr-qc astro-ph hep-th physics.class-ph
null
We model the massive dark object at the center of the Galaxy as a Schwarzschild black hole as well as Janis-Newman-Winicour naked singularities, characterized by the mass and scalar charge parameters, and study gravitational lensing (particularly time delay, magnification centroid, and total magnification) by them. W...
[ { "created": "Thu, 11 Oct 2007 19:28:32 GMT", "version": "v1" } ]
2008-11-26
[ [ "Virbhadra", "K. S.", "" ], [ "Keeton", "C. R.", "" ] ]
We model the massive dark object at the center of the Galaxy as a Schwarzschild black hole as well as Janis-Newman-Winicour naked singularities, characterized by the mass and scalar charge parameters, and study gravitational lensing (particularly time delay, magnification centroid, and total magnification) by them. We ...
2402.00081
Lu\'is Filipe Costa
L. Filipe O. Costa, F. Frutos-Alfaro, Jos\'e Nat\'ario, Michael Soffel
Comment on "The Tully-Fisher law and dark matter effects derived via modified symmetries" by Arraut Ivan
2 pages, no figures. Two minor typos in the text corrected, matches the final published version
EPL 146 (2024) 19002
10.1209/0295-5075/ad2728
null
gr-qc astro-ph.GA hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It has been claimed in I. Arraut, 2023 EPL 144 29003 [arXiv:2311.05652] that General Relativity can generate effects equivalent to dark matter, based on a "new modified symmetry that emerges at galactic scale". We show that (i) the spacetime considered is unphysical, violating energy conditions everywhere; (ii) actua...
[ { "created": "Wed, 31 Jan 2024 04:22:29 GMT", "version": "v1" }, { "created": "Thu, 4 Apr 2024 09:52:41 GMT", "version": "v2" } ]
2024-04-05
[ [ "Costa", "L. Filipe O.", "" ], [ "Frutos-Alfaro", "F.", "" ], [ "Natário", "José", "" ], [ "Soffel", "Michael", "" ] ]
It has been claimed in I. Arraut, 2023 EPL 144 29003 [arXiv:2311.05652] that General Relativity can generate effects equivalent to dark matter, based on a "new modified symmetry that emerges at galactic scale". We show that (i) the spacetime considered is unphysical, violating energy conditions everywhere; (ii) actuall...
2204.07589
Baofei Li
Bao-Fei Li and Parampreet Singh
Loop quantum cosmology and its gauge-covariant avatar: a weak curvature relationship
14 pages
null
10.1103/PhysRevD.106.026009
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We explore the relationship between the effective dynamics in standard loop quantum cosmology (LQC) based on holonomies and triads obtained from gauge-fixing fluxes, and a modification of LQC based on holonomies and gauge-covariant fluxes (referred to as gLQC). Both the models yield singularity resolution via a bounc...
[ { "created": "Fri, 15 Apr 2022 18:00:04 GMT", "version": "v1" } ]
2022-08-31
[ [ "Li", "Bao-Fei", "" ], [ "Singh", "Parampreet", "" ] ]
We explore the relationship between the effective dynamics in standard loop quantum cosmology (LQC) based on holonomies and triads obtained from gauge-fixing fluxes, and a modification of LQC based on holonomies and gauge-covariant fluxes (referred to as gLQC). Both the models yield singularity resolution via a bounce ...
0806.3602
Hongwei Yu
Hongwei Yu, Jianlin Zhang
Understanding Hawking radiation in the framework of open quantum systems
15 pages, no figures, Revtex4
Phys.Rev.D77:024031,2008; Erratum-ibid.D77:029904,2008
10.1103/PhysRevD.77.024031 10.1103/PhysRevD.77.029904
null
gr-qc quant-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the Hawking radiation in the framework of open quantum systems by examining the time evolution of a detector (modelled by a two-level atom) interacting with vacuum massless scalar fields. The dynamics of the detector is governed by a master equation obtained by tracing over the field degrees of freedom from ...
[ { "created": "Mon, 23 Jun 2008 02:05:16 GMT", "version": "v1" } ]
2014-11-18
[ [ "Yu", "Hongwei", "" ], [ "Zhang", "Jianlin", "" ] ]
We study the Hawking radiation in the framework of open quantum systems by examining the time evolution of a detector (modelled by a two-level atom) interacting with vacuum massless scalar fields. The dynamics of the detector is governed by a master equation obtained by tracing over the field degrees of freedom from th...
2308.01190
Arif Mohd
Musfar Muhamed Kozhikkal, Arif Mohd
Bogoliubov Transformation and Schrodinger Representation on Curved Space
15 pages
null
null
null
gr-qc
http://creativecommons.org/publicdomain/zero/1.0/
It is usually accepted that quantum dynamics described by Schrodinger equation that determines the evolution of states from one Cauchy surface to another is unitary. However, it has been known for some time that this expectation is not borne out in the conventional setting in which one envisages the dynamics on a fix...
[ { "created": "Wed, 2 Aug 2023 14:55:31 GMT", "version": "v1" } ]
2023-08-03
[ [ "Kozhikkal", "Musfar Muhamed", "" ], [ "Mohd", "Arif", "" ] ]
It is usually accepted that quantum dynamics described by Schrodinger equation that determines the evolution of states from one Cauchy surface to another is unitary. However, it has been known for some time that this expectation is not borne out in the conventional setting in which one envisages the dynamics on a fixed...
1605.06316
Andre Maeder
Andre Maeder
Scale invariant cosmology II: model equations and properties
8 pages, no figures
null
null
null
gr-qc astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We want to establish the basic properties of a scale invariant cosmology, that also accounts for the hypothesis of scale invariance of the empty space at large scales. We write the basic analytical properties of the scale invariant cosmological models. The hypothesis of scale invariance of the empty space at large sc...
[ { "created": "Thu, 19 May 2016 07:08:42 GMT", "version": "v1" } ]
2016-05-25
[ [ "Maeder", "Andre", "" ] ]
We want to establish the basic properties of a scale invariant cosmology, that also accounts for the hypothesis of scale invariance of the empty space at large scales. We write the basic analytical properties of the scale invariant cosmological models. The hypothesis of scale invariance of the empty space at large scal...
2108.00838
Peter Horvathy
P-M. Zhang, M. Elbistan, P. A. Horvathy
Particle motion in circularly polarized vacuum pp waves
22 pages many figures. Thoroughly revised and extended version with a modified title
null
10.1088/1361-6382/ac43d2
null
gr-qc hep-th math-ph math.MP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Bialynicki-Birula and Charzynski argued that a gravitational wave emitted during the merger of a black hole binary may be approximated by a circularly polarized wave which may in turn trap particles [1]. In this paper we consider particle motion in a class of gravitational waves which includes, besides circularly p...
[ { "created": "Mon, 2 Aug 2021 12:50:20 GMT", "version": "v1" }, { "created": "Mon, 29 Nov 2021 12:49:43 GMT", "version": "v2" } ]
2022-02-02
[ [ "Zhang", "P-M.", "" ], [ "Elbistan", "M.", "" ], [ "Horvathy", "P. A.", "" ] ]
Bialynicki-Birula and Charzynski argued that a gravitational wave emitted during the merger of a black hole binary may be approximated by a circularly polarized wave which may in turn trap particles [1]. In this paper we consider particle motion in a class of gravitational waves which includes, besides circularly polar...
2304.14187
Vincent Comeau
Vincent Comeau
Perturbative Correction to the Average Expansion Rate of Spacetimes with Perfect Fluids
null
null
null
null
gr-qc astro-ph.CO hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper discusses the leading-order correction induced by cosmological perturbations on the average expansion rate of an expanding spacetime, containing one or many perfect fluids. The calculation is carried out up to the second order in the perturbations, and is kept as general as possible. In particular, no appr...
[ { "created": "Thu, 27 Apr 2023 13:46:49 GMT", "version": "v1" } ]
2023-04-28
[ [ "Comeau", "Vincent", "" ] ]
This paper discusses the leading-order correction induced by cosmological perturbations on the average expansion rate of an expanding spacetime, containing one or many perfect fluids. The calculation is carried out up to the second order in the perturbations, and is kept as general as possible. In particular, no approx...