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1110.1356
Paulo Pitanga
Jair Koiller, Paulo R. Rodrigues and Paulo Pitanga
Non-Holonomic Connections Following \'Elie Cartan
null
Anais da Academia Brasileira de Ciencias 73 (2) 165 (2001)
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this note we revisit E. Cartan's address at the 1928 International Congress of Mathematicians at Bologna, Italy. The distributions considered here will be of the same class as those considered by Cartan, a special type which we call strongly non-holonomic. We set up the groundwork for using Cartan's method of equi...
[ { "created": "Thu, 6 Oct 2011 19:22:52 GMT", "version": "v1" } ]
2011-10-07
[ [ "Koiller", "Jair", "" ], [ "Rodrigues", "Paulo R.", "" ], [ "Pitanga", "Paulo", "" ] ]
In this note we revisit E. Cartan's address at the 1928 International Congress of Mathematicians at Bologna, Italy. The distributions considered here will be of the same class as those considered by Cartan, a special type which we call strongly non-holonomic. We set up the groundwork for using Cartan's method of equiva...
2305.07123
Bekir Can L\"utf\"uo\u{g}lu
B. Hamil and B. C. L\"utf\"uo\u{g}lu
Thermodynamics and Shadows of quantum-corrected Reissner-Nordstr\"om black hole surrounded by quintessence
21 pages, 4 Tables, 7 Figures
Phys. Dark Universe 42, 101293 (2023)
10.1016/j.dark.2023.101293
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this work, we consider the quantum-corrected Reissner-Nordstr\"om black hole surrounded by quintessence matter and examine its thermodynamics and shadow. To this end, we handle the quantum-corrected metric of the black hole, which is given by Wu and Lui in 2022, and couple the quintessence matter field effects to ...
[ { "created": "Thu, 11 May 2023 20:23:29 GMT", "version": "v1" }, { "created": "Mon, 21 Aug 2023 15:59:43 GMT", "version": "v2" } ]
2023-08-22
[ [ "Hamil", "B.", "" ], [ "Lütfüoğlu", "B. C.", "" ] ]
In this work, we consider the quantum-corrected Reissner-Nordstr\"om black hole surrounded by quintessence matter and examine its thermodynamics and shadow. To this end, we handle the quantum-corrected metric of the black hole, which is given by Wu and Lui in 2022, and couple the quintessence matter field effects to th...
gr-qc/0102034
Enric Verdaguer
Enric Verdaguer
Stochastic semiclassical gravity and fluctuations during inflation
9 pages, Proceedings of the conference on Applied and differential geometry, Lie algebras and general relativity, Thessaloniki 2000
null
null
null
gr-qc
null
Stochastic semiclassical gravity is a theory for the interaction of gravity with quantum matter fields which goes beyond the semiclassical limit. The theory predicts stochastic fluctuations of the classical gravitational field induced by the quantum fluctuations of the stress energy tensor of the matter fields. Here ...
[ { "created": "Thu, 8 Feb 2001 19:05:31 GMT", "version": "v1" } ]
2007-05-23
[ [ "Verdaguer", "Enric", "" ] ]
Stochastic semiclassical gravity is a theory for the interaction of gravity with quantum matter fields which goes beyond the semiclassical limit. The theory predicts stochastic fluctuations of the classical gravitational field induced by the quantum fluctuations of the stress energy tensor of the matter fields. Here we...
2211.13604
Ruxandra Bondarescu
Ruxandra Bondarescu, Helena Ubach, Oleg Bulashenko and Andrew P. Lundgren
Compact Binaries through a Lens: Silent vs. Detectable Microlensing for the LIGO-Virgo-KAGRA Gravitational Wave Observatories
17 pages, 12 Figures. Updated References. Submitted to Phys. Rev. D
Phys. Rev. D 108, (2023) 084033
10.1103/PhysRevD.108.084033
null
gr-qc astro-ph.CO astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Massive objects located between Earth and a compact binary merger can act as a magnifying glass improving the sensitivity of gravitational wave detectors to distant events. Depending on the parameters of the system, a point mass lens between the detector and the source can either lead to a smooth frequency-dependent ...
[ { "created": "Thu, 24 Nov 2022 13:45:31 GMT", "version": "v1" }, { "created": "Sun, 11 Dec 2022 21:00:56 GMT", "version": "v2" }, { "created": "Thu, 26 Oct 2023 11:57:46 GMT", "version": "v3" } ]
2023-10-27
[ [ "Bondarescu", "Ruxandra", "" ], [ "Ubach", "Helena", "" ], [ "Bulashenko", "Oleg", "" ], [ "Lundgren", "Andrew P.", "" ] ]
Massive objects located between Earth and a compact binary merger can act as a magnifying glass improving the sensitivity of gravitational wave detectors to distant events. Depending on the parameters of the system, a point mass lens between the detector and the source can either lead to a smooth frequency-dependent am...
gr-qc/0608022
Farrukh Fattoyev Jabborovich
B. J. Ahmedov, A. V. Khugaev
Remarks on Papapetrou Class of Vacuum Solutions of Einstein Equations
8 pages
Int.J.Mod.Phys. D13 (2006) 1823-1830
10.1142/S0218271804004748
null
gr-qc astro-ph
null
Class of axially symmetric solutions of vacuum Einstein field equations including the Papapetrou solution as particular case has been found. It has been shown that the derived solution describes the external axial symmetric gravitational field of the source with nonvanishing mass. The general solution is obtained for...
[ { "created": "Fri, 4 Aug 2006 09:03:17 GMT", "version": "v1" } ]
2009-11-11
[ [ "Ahmedov", "B. J.", "" ], [ "Khugaev", "A. V.", "" ] ]
Class of axially symmetric solutions of vacuum Einstein field equations including the Papapetrou solution as particular case has been found. It has been shown that the derived solution describes the external axial symmetric gravitational field of the source with nonvanishing mass. The general solution is obtained for t...
1709.04016
Santiago Esteban Perez Bergliaffa
Luz Marina Reyes and Santiago Esteban Perez Bergliaffa
On the emergence of the ${\bf\Lambda}$CDM model from self-interacting Brans-Dicke theory in ${\bf d= 5}$
7 pages, 7 figures
null
10.1140/epjc/s10052-017-5497-y
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate whether a self-interacting Brans-Dicke theory in $d=5$ without matter and with a time-dependent metric can describe, after dimensional reduction to $d=4$, the FLRW model with accelerated expansion and non-relativistic matter. By rewriting the effective 4-dimensional theory as an autonomous three-dimens...
[ { "created": "Tue, 12 Sep 2017 18:49:50 GMT", "version": "v1" } ]
2018-02-14
[ [ "Reyes", "Luz Marina", "" ], [ "Bergliaffa", "Santiago Esteban Perez", "" ] ]
We investigate whether a self-interacting Brans-Dicke theory in $d=5$ without matter and with a time-dependent metric can describe, after dimensional reduction to $d=4$, the FLRW model with accelerated expansion and non-relativistic matter. By rewriting the effective 4-dimensional theory as an autonomous three-dimensio...
1512.08346
Claus Kiefer
Claus Kiefer
Quantum black hole without singularity
5 pages, invited contribution to the BH6 session at the Marcel Grossmann Conference MG14
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss the quantization of a spherical dust shell in a rigorous manner. Classically, the shell can collapse to form a black hole with a singularity. In the quantum theory, we construct a well-defined self-adjoint extension for the Hamilton operator. As a result, the evolution is unitary and the singularity is avo...
[ { "created": "Mon, 28 Dec 2015 08:50:02 GMT", "version": "v1" } ]
2015-12-29
[ [ "Kiefer", "Claus", "" ] ]
We discuss the quantization of a spherical dust shell in a rigorous manner. Classically, the shell can collapse to form a black hole with a singularity. In the quantum theory, we construct a well-defined self-adjoint extension for the Hamilton operator. As a result, the evolution is unitary and the singularity is avoid...
2311.11752
Jo\~ao Lu\'is Rosa
Jo\~ao Lu\'is Rosa
Junction conditions in gravity theories with extra scalar degrees of freedom
29 pages. V2: published version
Phys. Rev. D 109, 064018 (2024)
10.1103/PhysRevD.109.064018
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this work we present a general method to obtain the junction conditions of modified theories of gravity whose action can be written in the form $f\left(X_1,...,X_n\right)$, where $X_1$ to $X_n$ are any combination of scalar dependencies, e.g. the Ricci scalar $R$, the trace of the stress-energy tensor $T$, the Gau...
[ { "created": "Mon, 20 Nov 2023 13:27:44 GMT", "version": "v1" }, { "created": "Fri, 8 Mar 2024 15:48:21 GMT", "version": "v2" } ]
2024-03-11
[ [ "Rosa", "João Luís", "" ] ]
In this work we present a general method to obtain the junction conditions of modified theories of gravity whose action can be written in the form $f\left(X_1,...,X_n\right)$, where $X_1$ to $X_n$ are any combination of scalar dependencies, e.g. the Ricci scalar $R$, the trace of the stress-energy tensor $T$, the Gauss...
gr-qc/9605068
Eli Hawkins
Eli Hawkins
Hamiltonian Gravity and Noncommutative Geometry
22 pages, AMS-LaTeX. Some improvements - mainly to sections 8 and 9. Typographical errors to equations in appendix corrected
Commun.Math.Phys. 187 (1997) 471-489
10.1007/s002200050145
CGPG-96/5-8
gr-qc hep-th
null
A version of foliated spacetime is constructed in which the spatial geometry is described as a time dependent noncommutative geometry. The ADM version of the gravitational action is expressed in terms of these variables. It is shown that the vector constraint is obtained without the need for an extraneous shift vecto...
[ { "created": "Thu, 30 May 1996 21:47:19 GMT", "version": "v1" }, { "created": "Thu, 6 Mar 1997 23:00:58 GMT", "version": "v2" }, { "created": "Thu, 8 May 1997 21:18:46 GMT", "version": "v3" } ]
2009-10-28
[ [ "Hawkins", "Eli", "" ] ]
A version of foliated spacetime is constructed in which the spatial geometry is described as a time dependent noncommutative geometry. The ADM version of the gravitational action is expressed in terms of these variables. It is shown that the vector constraint is obtained without the need for an extraneous shift vector ...
gr-qc/0502066
Brendan Foster
Brendan Z. Foster
Metric Redefinitions in Einstein-Aether Theory
11 pages; v.2: Some clarifying remarks added, to appear in PRD
Phys.Rev. D72 (2005) 044017
10.1103/PhysRevD.72.044017
null
gr-qc
null
`Einstein-Aether' theory, in which gravity couples to a dynamical, time-like, unit-norm vector field, provides a means for studying Lorentz violation in a generally covariant setting. Demonstrated here is the effect of a redefinition of the metric and vector field in terms of the original fields and two free paramete...
[ { "created": "Mon, 14 Feb 2005 20:46:49 GMT", "version": "v1" }, { "created": "Mon, 1 Aug 2005 17:44:22 GMT", "version": "v2" } ]
2009-11-11
[ [ "Foster", "Brendan Z.", "" ] ]
`Einstein-Aether' theory, in which gravity couples to a dynamical, time-like, unit-norm vector field, provides a means for studying Lorentz violation in a generally covariant setting. Demonstrated here is the effect of a redefinition of the metric and vector field in terms of the original fields and two free parameters...
2201.12458
E. Kyriakopoulos
E. Kyriakopoulos
Regular Interior Solutions to the Solution of Kerr which Satisfy the Weak and the Strong Energy Conditions
25 pages, 15 figures
J. Math. Phys. 63, 012501 (2022)
10.1063/5.0080367
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The line element of a class of solutions which match to the solution of Kerr on an oblate spheroid if the two functions $ F(r)$ and $H(r)$ on which it depends satisfy certain matching conditions is presented. The non vanishing components of the Ricci tensor $R_{\mu\nu}$, the Ricci scalar $ R$, the second order curvat...
[ { "created": "Sat, 29 Jan 2022 00:05:14 GMT", "version": "v1" } ]
2022-02-01
[ [ "Kyriakopoulos", "E.", "" ] ]
The line element of a class of solutions which match to the solution of Kerr on an oblate spheroid if the two functions $ F(r)$ and $H(r)$ on which it depends satisfy certain matching conditions is presented. The non vanishing components of the Ricci tensor $R_{\mu\nu}$, the Ricci scalar $ R$, the second order curvatur...
1507.05669
Sumanta Chakraborty
T. Padmanabhan, Sumanta Chakraborty and Dawood Kothawala
Spacetime with zero point length is two-dimensional at the Planck scale
published version
Gen. Rel. Grav. 48, 55 (2016)
10.1007/s10714-016-2053-2
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It is generally believed that any quantum theory of gravity should have a generic feature --- a quantum of length. We provide a physical ansatz to obtain an effective non-local metric tensor starting from the standard metric tensor such that the spacetime acquires a zero-point-length $\ell _{0}$ of the order of the P...
[ { "created": "Thu, 16 Jul 2015 20:00:58 GMT", "version": "v1" }, { "created": "Mon, 3 Aug 2015 06:29:34 GMT", "version": "v2" }, { "created": "Thu, 7 Apr 2016 04:15:31 GMT", "version": "v3" } ]
2016-04-08
[ [ "Padmanabhan", "T.", "" ], [ "Chakraborty", "Sumanta", "" ], [ "Kothawala", "Dawood", "" ] ]
It is generally believed that any quantum theory of gravity should have a generic feature --- a quantum of length. We provide a physical ansatz to obtain an effective non-local metric tensor starting from the standard metric tensor such that the spacetime acquires a zero-point-length $\ell _{0}$ of the order of the Pla...
1703.03710
Llibert Arest\'e Sal\'o
Jaume Haro, Jaume Amor\'os and Llibert Arest\'e Sal\'o
The matter-ekpyrotic bounce scenario in Loop Quantum Cosmology
39 pages, 19 figures. Version accepted for publication in JCAP
JCAP 09 (2017) 002
10.1088/1475-7516/2017/09/002
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We will perform a detailed study of the matter-ekpyrotic bouncing scenario in Loop Quantum Cosmology using the methods of the dynamical systems theory. We will show that when the background is driven by a single scalar field, at very late times, in the contracting phase, all orbits depict a matter dominated Universe,...
[ { "created": "Fri, 10 Mar 2017 15:16:04 GMT", "version": "v1" }, { "created": "Mon, 13 Mar 2017 15:51:38 GMT", "version": "v2" }, { "created": "Sun, 13 Aug 2017 16:01:26 GMT", "version": "v3" } ]
2017-09-04
[ [ "Haro", "Jaume", "" ], [ "Amorós", "Jaume", "" ], [ "Saló", "Llibert Aresté", "" ] ]
We will perform a detailed study of the matter-ekpyrotic bouncing scenario in Loop Quantum Cosmology using the methods of the dynamical systems theory. We will show that when the background is driven by a single scalar field, at very late times, in the contracting phase, all orbits depict a matter dominated Universe, w...
2112.14538
Laszlo B. Szabados
L\'aszl\'o B. Szabados
A note on Penrose's Spin-Geometry Theorem and the geometry of `empirical quantum angles'
10 pages; v2: a convention changed to be compatible with the standard one, the link in ref [5] is added, one reference is updated; v3: references added, typos corrected, discussion improved; v4: references updated and added, final version (Foundations of Physics)
Foundations of Physics (2022) 52:96
10.1007/s10701-022-00616-3
null
gr-qc quant-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In the traditional formalism of quantum mechanics, a simple direct proof of (a version of) the Spin Geometry Theorem of Penrose is given; and the structure of a model of the `space of the quantum directions', defined in terms of elementary $SU(2)$-invariant observables of the quantum mechanical systems, is sketched.
[ { "created": "Wed, 29 Dec 2021 13:28:27 GMT", "version": "v1" }, { "created": "Thu, 10 Mar 2022 11:37:24 GMT", "version": "v2" }, { "created": "Tue, 12 Jul 2022 19:01:33 GMT", "version": "v3" }, { "created": "Thu, 18 Aug 2022 11:21:41 GMT", "version": "v4" } ]
2022-09-08
[ [ "Szabados", "László B.", "" ] ]
In the traditional formalism of quantum mechanics, a simple direct proof of (a version of) the Spin Geometry Theorem of Penrose is given; and the structure of a model of the `space of the quantum directions', defined in terms of elementary $SU(2)$-invariant observables of the quantum mechanical systems, is sketched.
gr-qc/0411075
Mihalis Dafermos
Mihalis Dafermos and Alan Rendall
An extension principle for the Einstein-Vlasov system in spherical symmetry
19 pages, 2 figures
Annales Henri Poincare 6 (2005) 1137-1155
10.1007/s00023-005-0235-7
null
gr-qc
null
We prove that "first singularities" in the non-trapped region of the maximal development of spherically symmetric asymptotically flat data for the Einstein-Vlasov system must necessarily emanate from the center. The notion of "first" depends only on the causal structure and can be described in the language of termina...
[ { "created": "Mon, 15 Nov 2004 17:48:06 GMT", "version": "v1" } ]
2009-11-10
[ [ "Dafermos", "Mihalis", "" ], [ "Rendall", "Alan", "" ] ]
We prove that "first singularities" in the non-trapped region of the maximal development of spherically symmetric asymptotically flat data for the Einstein-Vlasov system must necessarily emanate from the center. The notion of "first" depends only on the causal structure and can be described in the language of terminal ...
2109.02295
Ying Wang
Wei Sun, Ying Wang, Fuyao Liu, Xin Wu
Applying explicit symplectic integrator to study chaos of charged particles around magnetized Kerr black hole
10 pages,20 figures
null
10.1140/epjc/s10052-021-09579-7
null
gr-qc astro-ph.IM nlin.CD physics.comp-ph
http://creativecommons.org/licenses/by/4.0/
In a recent work of Wu, Wang, Sun and Liu, a second-order explicit symplectic integrator was proposed for the integrable Kerr spacetime geometry. It is still suited for simulating the nonintegrable dynamics of charged particles moving around the Kerr black hole embedded in an external magnetic field. Its successful c...
[ { "created": "Mon, 6 Sep 2021 08:54:55 GMT", "version": "v1" } ]
2021-09-07
[ [ "Sun", "Wei", "" ], [ "Wang", "Ying", "" ], [ "Liu", "Fuyao", "" ], [ "Wu", "Xin", "" ] ]
In a recent work of Wu, Wang, Sun and Liu, a second-order explicit symplectic integrator was proposed for the integrable Kerr spacetime geometry. It is still suited for simulating the nonintegrable dynamics of charged particles moving around the Kerr black hole embedded in an external magnetic field. Its successful con...
1901.00938
David Anderson
David Anderson, Paulo Freire, Nicol\'as Yunes
Binary Pulsar constraints on massless scalar-tensor theories using Bayesian statistics
15 pages, 7 figures, Submitted to CQG
null
10.1088/1361-6382/ab3a1c
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Binary pulsars provide some of the tightest current constraints on modified theories of gravity and these constraints will only get tighter as radio astronomers continue timing these systems. These binary pulsars are particularly good at constraining scalar-tensor theories in which gravity is mediated by a scalar fie...
[ { "created": "Thu, 3 Jan 2019 23:09:45 GMT", "version": "v1" } ]
2019-12-11
[ [ "Anderson", "David", "" ], [ "Freire", "Paulo", "" ], [ "Yunes", "Nicolás", "" ] ]
Binary pulsars provide some of the tightest current constraints on modified theories of gravity and these constraints will only get tighter as radio astronomers continue timing these systems. These binary pulsars are particularly good at constraining scalar-tensor theories in which gravity is mediated by a scalar field...
gr-qc/9910085
null
Jacek Jezierski
Trautman-Bondi Mass for Scalar Field and Gravity
LaTeX2e, 14 pages, to appear in Rep. on Math. Physics
Coherent States, Quantization, and Gravity; Proceedings of the XVII Workshop on Geometric Methods in Physics, 1998
null
UW-KMMF-99-03
gr-qc
null
The energy at null infinity is presented with the help of a simple example of a massless scalar field in Minkowski spacetime. It is also discussed for Einstein gravity. In particular, various aspects of the loss of the energy in the radiating regime are shown.
[ { "created": "Mon, 25 Oct 1999 13:25:33 GMT", "version": "v1" } ]
2013-11-12
[ [ "Jezierski", "Jacek", "" ] ]
The energy at null infinity is presented with the help of a simple example of a massless scalar field in Minkowski spacetime. It is also discussed for Einstein gravity. In particular, various aspects of the loss of the energy in the radiating regime are shown.
gr-qc/0204004
Sawa Manoff
Sawa Manoff
Mechanics of Continuous Media in $(\bar{L}_{n},g)$-Spaces. IV. Stress (Tension) Tensor
38 pages, LaTeX
null
null
null
gr-qc
null
Basic notions of continuous media mechanics are introduced for spaces with affine connections and metrics. Stress (tension) tensors are considered, obtained by the use of the method of Lagrangians with covariant derivatives (MLCD). On the basis of the covariant Noether's identities for the energy-momentum tensors, Na...
[ { "created": "Mon, 1 Apr 2002 11:23:51 GMT", "version": "v1" } ]
2007-05-23
[ [ "Manoff", "Sawa", "" ] ]
Basic notions of continuous media mechanics are introduced for spaces with affine connections and metrics. Stress (tension) tensors are considered, obtained by the use of the method of Lagrangians with covariant derivatives (MLCD). On the basis of the covariant Noether's identities for the energy-momentum tensors, Navi...
gr-qc/9601007
Jorge Griego
Jorge Griego
Extended knots and the space of states of quantum gravity
19 pages
Nucl.Phys. B473 (1996) 291-307
10.1016/0550-3213(96)00235-0
IFFC 96-01
gr-qc
null
In the loop representation the quantum constraints of gravity can be solved. This fact allowed significant progress in the understanding of the space of states of the theory. The analysis of the constraints over loop dependent wavefunctions has been traditionally based upon geometric (in contrast to analytic) propert...
[ { "created": "Sun, 7 Jan 1996 01:19:30 GMT", "version": "v1" } ]
2009-10-28
[ [ "Griego", "Jorge", "" ] ]
In the loop representation the quantum constraints of gravity can be solved. This fact allowed significant progress in the understanding of the space of states of the theory. The analysis of the constraints over loop dependent wavefunctions has been traditionally based upon geometric (in contrast to analytic) propertie...
1009.4923
Tanja Hinderer
Eanna E. Flanagan (Cornell), Tanja Hinderer (Caltech)
Transient resonances in the inspirals of point particles into black holes
4 pages, 1 figure, minor corrections
null
10.1103/PhysRevLett.109.071102
null
gr-qc astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show that transient resonances occur in the two body problem in general relativity, in the highly relativistic, extreme mass-ratio regime for spinning black holes. These resonances occur when the ratio of polar and radial orbital frequencies, which is slowly evolving under the influence of gravitational radiation ...
[ { "created": "Fri, 24 Sep 2010 19:52:21 GMT", "version": "v1" }, { "created": "Mon, 27 Sep 2010 20:39:38 GMT", "version": "v2" }, { "created": "Wed, 11 Jul 2012 21:22:42 GMT", "version": "v3" } ]
2013-05-30
[ [ "Flanagan", "Eanna E.", "", "Cornell" ], [ "Hinderer", "Tanja", "", "Caltech" ] ]
We show that transient resonances occur in the two body problem in general relativity, in the highly relativistic, extreme mass-ratio regime for spinning black holes. These resonances occur when the ratio of polar and radial orbital frequencies, which is slowly evolving under the influence of gravitational radiation re...
1611.09781
Pantelis Apostolopoulos
Pantelis S. Apostolopoulos
Intrinsic Conformal Symmetries in Szekeres models
6 pages (uses iopart style/class files); (v2) some minor amendments to match published version in Modern Physics Letters A
Mod.Phys.Lett. A32 (2017) no.19, 1750099
10.1142/S0217732317500997
null
gr-qc math-ph math.MP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show that Spatially Inhomogeneous (SI) and Irrotational dust models admit a \emph{6-dimensional algebra } of \emph{Intrinsic Conformal Vector Fields} (ICVFs) $\mathbf{X}_{\alpha }$ satisfying $p_{a}^{c}p_{b}^{d}\mathcal{L}_{\mathbf{X}_{\alpha }}p_{cd}=2\phi (\mathbf{X}_{\alpha })p_{ab}$ where $p_{ab}$ is the assoc...
[ { "created": "Tue, 29 Nov 2016 18:46:37 GMT", "version": "v1" }, { "created": "Mon, 22 May 2017 15:49:53 GMT", "version": "v2" } ]
2017-06-13
[ [ "Apostolopoulos", "Pantelis S.", "" ] ]
We show that Spatially Inhomogeneous (SI) and Irrotational dust models admit a \emph{6-dimensional algebra } of \emph{Intrinsic Conformal Vector Fields} (ICVFs) $\mathbf{X}_{\alpha }$ satisfying $p_{a}^{c}p_{b}^{d}\mathcal{L}_{\mathbf{X}_{\alpha }}p_{cd}=2\phi (\mathbf{X}_{\alpha })p_{ab}$ where $p_{ab}$ is the associa...
2008.06728
Peter K.F. Kuhfittig
Peter K.F. Kuhfittig
Noncommutative-geometry wormholes without exotic matter
6 pages, no figures
Adv. Stud. Theor. Phys.,vol. 14, 219-225 (2020)
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A fundamental property of Morris-Thorne wormholes is the so-called flare-out condition that automatically results in a violation of the null energy condition (NEC) in classical general relativity. By contrast, in $f(R)$ modified gravity, the material threading the wormhole may actually satisfy the NEC, while, at the ...
[ { "created": "Sat, 15 Aug 2020 14:58:23 GMT", "version": "v1" }, { "created": "Wed, 19 Aug 2020 15:52:33 GMT", "version": "v2" } ]
2020-08-20
[ [ "Kuhfittig", "Peter K. F.", "" ] ]
A fundamental property of Morris-Thorne wormholes is the so-called flare-out condition that automatically results in a violation of the null energy condition (NEC) in classical general relativity. By contrast, in $f(R)$ modified gravity, the material threading the wormhole may actually satisfy the NEC, while, at the sa...
gr-qc/9701007
Renate Loll
R. Loll (AEI, Potsdam and ESI, Vienna)
Latticing quantum gravity
7 pages, TeX, 1 figure (epsf); contribution to Santa Margherita Conference on Constrained Dynamics and Quantum Gravity
Nucl.Phys.Proc.Suppl. 57 (1997) 255-258
10.1016/S0920-5632(97)00398-8
null
gr-qc
null
I discuss some aspects of a lattice approach to canonical quantum gravity in a connection formulation, discuss how it differs from the continuum construction, and compare the spectra of geometric operators - encoding information about components of the spatial metric - for some simple lattice quantum states.
[ { "created": "Mon, 6 Jan 1997 22:45:17 GMT", "version": "v1" } ]
2009-10-30
[ [ "Loll", "R.", "", "AEI, Potsdam and ESI, Vienna" ] ]
I discuss some aspects of a lattice approach to canonical quantum gravity in a connection formulation, discuss how it differs from the continuum construction, and compare the spectra of geometric operators - encoding information about components of the spatial metric - for some simple lattice quantum states.
2008.10332
Jianwei Mei
Jianwei Mei, Yan-Zheng Bai, Jiahui Bao, Enrico Barausse, Lin Cai, Enrico Canuto, Bin Cao, Wei-Ming Chen, Yu Chen, Yan-Wei Ding, Hui-Zong Duan, Huimin Fan, Wen-Fan Feng, Honglin Fu, Qing Gao, TianQuan Gao, Yungui Gong, Xingyu Gou, Chao-Zheng Gu, De-Feng Gu, Zi-Qi He, Martin Hendry, Wei Hong, Xin-Chun Hu, Yi-Ming...
The TianQin project: current progress on science and technology
16 pages, 1 figure, invited article to a special section in PTEP
null
10.1093/ptep/ptaa114
null
gr-qc astro-ph.IM
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
TianQin is a planned space-based gravitational wave (GW) observatory consisting of three earth orbiting satellites with an orbital radius of about $10^5~{\rm km}$. The satellites will form a equilateral triangle constellation the plane of which is nearly perpendicular to the ecliptic plane. TianQin aims to detect GWs...
[ { "created": "Mon, 24 Aug 2020 11:45:05 GMT", "version": "v1" } ]
2020-08-25
[ [ "Mei", "Jianwei", "" ], [ "Bai", "Yan-Zheng", "" ], [ "Bao", "Jiahui", "" ], [ "Barausse", "Enrico", "" ], [ "Cai", "Lin", "" ], [ "Canuto", "Enrico", "" ], [ "Cao", "Bin", "" ], [ "Chen", "Wei-...
TianQin is a planned space-based gravitational wave (GW) observatory consisting of three earth orbiting satellites with an orbital radius of about $10^5~{\rm km}$. The satellites will form a equilateral triangle constellation the plane of which is nearly perpendicular to the ecliptic plane. TianQin aims to detect GWs b...
1101.2198
Travis Garrett
Travis Garrett
The Observer Class Hypothesis
14 pages, 1 figure
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The discovery of a small cosmological constant has stimulated interest in the measure problem. One should expect to be a typical observer, but defining such a thing is difficult in the vastness of an eternally inflating universe. We propose that a crucial prerequisite is understanding why one should exist as an obser...
[ { "created": "Tue, 11 Jan 2011 20:40:50 GMT", "version": "v1" } ]
2011-01-12
[ [ "Garrett", "Travis", "" ] ]
The discovery of a small cosmological constant has stimulated interest in the measure problem. One should expect to be a typical observer, but defining such a thing is difficult in the vastness of an eternally inflating universe. We propose that a crucial prerequisite is understanding why one should exist as an observe...
2302.10233
Francisco M. Blanco
Francisco M. Blanco and \'Eanna \'E. Flanagan
Motion of a spinning particle under the conservative piece of the self-force is Hamiltonian to first order in mass and spin
7 pages
null
10.1103/PhysRevD.107.124017
null
gr-qc
http://creativecommons.org/licenses/by/4.0/
We consider the motion of a point particle with spin in a stationary spacetime. We define, following Witzany (2019) and later Ramond (2022), a twelve dimensional Hamiltonian dynamical system whose orbits coincide with the solutions of the Mathisson-Papapetrou-Dixon equations of motion with the Tulczyjew-Dixon spin su...
[ { "created": "Mon, 20 Feb 2023 19:05:56 GMT", "version": "v1" }, { "created": "Thu, 4 May 2023 04:54:22 GMT", "version": "v2" } ]
2023-06-21
[ [ "Blanco", "Francisco M.", "" ], [ "Flanagan", "Éanna É.", "" ] ]
We consider the motion of a point particle with spin in a stationary spacetime. We define, following Witzany (2019) and later Ramond (2022), a twelve dimensional Hamiltonian dynamical system whose orbits coincide with the solutions of the Mathisson-Papapetrou-Dixon equations of motion with the Tulczyjew-Dixon spin supp...
1902.08734
Gauranga Samanta
Karim Mosani and Gauranga C. Samanta
Dynamics of General Barotropic Stellar Fluid in the Framework of $R+2\alpha T$ Gravity
14 pages, 17 figures
null
10.1142/S0217732320500893
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Gravitational collapse of a spherically symmetric homogeneous perfect barotropic fluid with linear as well as polytropic type Equation of State (EoS) has been investigated in the framework of a linear model of $f(R,T)$ gravity. This modified gravity has the potential to explain the observed cosmic acceleration. The c...
[ { "created": "Sat, 23 Feb 2019 04:06:05 GMT", "version": "v1" } ]
2020-05-06
[ [ "Mosani", "Karim", "" ], [ "Samanta", "Gauranga C.", "" ] ]
Gravitational collapse of a spherically symmetric homogeneous perfect barotropic fluid with linear as well as polytropic type Equation of State (EoS) has been investigated in the framework of a linear model of $f(R,T)$ gravity. This modified gravity has the potential to explain the observed cosmic acceleration. The cal...
1805.11591
Petya Nedkova
Galin Gyulchev, Petya Nedkova, Vassil Tinchev, Stoytcho Yazadjiev
On the shadow of rotating traversable wormholes
19 pages; 12 figures
null
10.1140/epjc/s10052-018-6012-9
null
gr-qc astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We revisit the shadow of rotating traversable wormholes discussing the role of the wormhole throat in the shadow formation. For certain classes of wormholes the throat serves as a potential barrier for light rays with particular impact parameters, thus modifying the shadow shape. We consider a couple of wormhole solu...
[ { "created": "Tue, 29 May 2018 17:18:27 GMT", "version": "v1" } ]
2018-08-01
[ [ "Gyulchev", "Galin", "" ], [ "Nedkova", "Petya", "" ], [ "Tinchev", "Vassil", "" ], [ "Yazadjiev", "Stoytcho", "" ] ]
We revisit the shadow of rotating traversable wormholes discussing the role of the wormhole throat in the shadow formation. For certain classes of wormholes the throat serves as a potential barrier for light rays with particular impact parameters, thus modifying the shadow shape. We consider a couple of wormhole soluti...
2206.00768
Arnab Mukherjee
Arnab Mukherjee, Sunandan Gangopadhyay and A. S. Majumdar
Unruh quantum Otto engine in the presence of a reflecting boundary
Version accepted in JHEP
JHEP 09 (2022) 105
10.1007/JHEP09(2022)105
null
gr-qc hep-th
http://creativecommons.org/licenses/by/4.0/
We introduce a new model of relativistic quantum analogue of the classical Otto engine in the presence of a perfectly reflecting boundary. A single qubit acts as the working substance interacting with a massless quantum scalar field, with the boundary obeying the Dirichlet condition. The quantum vacuum serves as a th...
[ { "created": "Fri, 20 May 2022 04:11:51 GMT", "version": "v1" }, { "created": "Sat, 27 Aug 2022 10:04:12 GMT", "version": "v2" } ]
2022-09-19
[ [ "Mukherjee", "Arnab", "" ], [ "Gangopadhyay", "Sunandan", "" ], [ "Majumdar", "A. S.", "" ] ]
We introduce a new model of relativistic quantum analogue of the classical Otto engine in the presence of a perfectly reflecting boundary. A single qubit acts as the working substance interacting with a massless quantum scalar field, with the boundary obeying the Dirichlet condition. The quantum vacuum serves as a ther...
1111.7231
Tamerlan Saidov
Tamerlan Saidov
The Compactification Problems of Additional Dimensions in Multidimensional Cosmological Theories
126 pages, 33 figures; the PhD thesis for physical and mathematical science
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Multidimensionality of our Universe is one of the most intriguing assumption in modern physics. It follows naturally from theories unifying different fundamental interactions with gravity, e.g. M/string theory. The idea has received a great deal of renewed attention over the last few years. However, it also brings a ...
[ { "created": "Wed, 30 Nov 2011 16:22:32 GMT", "version": "v1" } ]
2011-12-01
[ [ "Saidov", "Tamerlan", "" ] ]
Multidimensionality of our Universe is one of the most intriguing assumption in modern physics. It follows naturally from theories unifying different fundamental interactions with gravity, e.g. M/string theory. The idea has received a great deal of renewed attention over the last few years. However, it also brings a ro...
2207.06429
Raimon Luna
Raimon Luna, Gabriele Bozzola, Vitor Cardoso, Vasileios Paschalidis, Miguel Zilh\~ao
Kicks in charged black hole binaries
12 pages, 10 figures. v2: Matches published version
Phys.Rev.D 106 (2022) 8, 084017
10.1103/PhysRevD.106.084017
null
gr-qc astro-ph.HE hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We compute the emission of linear momentum (kicks) by both gravitational and electromagnetic radiation in fully general-relativistic numerical evolutions of quasi-circular charged black hole binaries. We derive analytical expressions for slowly moving bodies and explore numerically a variety of mass ratios and charge...
[ { "created": "Wed, 13 Jul 2022 18:00:01 GMT", "version": "v1" }, { "created": "Wed, 9 Nov 2022 17:31:10 GMT", "version": "v2" } ]
2022-11-10
[ [ "Luna", "Raimon", "" ], [ "Bozzola", "Gabriele", "" ], [ "Cardoso", "Vitor", "" ], [ "Paschalidis", "Vasileios", "" ], [ "Zilhão", "Miguel", "" ] ]
We compute the emission of linear momentum (kicks) by both gravitational and electromagnetic radiation in fully general-relativistic numerical evolutions of quasi-circular charged black hole binaries. We derive analytical expressions for slowly moving bodies and explore numerically a variety of mass ratios and charge-t...
2307.06139
Sheref Nasereldin
Sheref Nasereldin and Kayll Lake
Constructing Maximal Extensions of the Vaidya Metric in Israel Coordinates: I. Integration of the Field Equations
8 pages, 1 figure, 2 tables
null
10.1103/PhysRevD.108.124064
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper explores a complete representation of the Vaidya model, a radial flux of radiation in the eikonal approximation, used for modeling various phenomena in both classical and semi-classical General Relativity and Astrophysics. The majority of the applications of the Vaidya model have been formulated in an inco...
[ { "created": "Sun, 9 Jul 2023 04:58:49 GMT", "version": "v1" }, { "created": "Fri, 14 Jul 2023 00:29:45 GMT", "version": "v2" }, { "created": "Mon, 30 Oct 2023 17:35:10 GMT", "version": "v3" }, { "created": "Tue, 26 Dec 2023 14:20:42 GMT", "version": "v4" } ]
2023-12-27
[ [ "Nasereldin", "Sheref", "" ], [ "Lake", "Kayll", "" ] ]
This paper explores a complete representation of the Vaidya model, a radial flux of radiation in the eikonal approximation, used for modeling various phenomena in both classical and semi-classical General Relativity and Astrophysics. The majority of the applications of the Vaidya model have been formulated in an incomp...
1707.07566
Donald Lynden-Bell Prof
D. Lynden-Bell, S.M. Chitre
Does Viscosity turn inflation into the CMB and $\Lambda$
8 pages , 2 figures
null
null
null
gr-qc astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Consideration of the entropy production in the creation of the CMB leads to a simple model of the evolution of the universe during this period which suggests a connection between the small observed acceleration term and the early inflation of a closed universe. From this we find an unexpected relationship between the...
[ { "created": "Mon, 24 Jul 2017 14:11:47 GMT", "version": "v1" } ]
2017-07-25
[ [ "Lynden-Bell", "D.", "" ], [ "Chitre", "S. M.", "" ] ]
Consideration of the entropy production in the creation of the CMB leads to a simple model of the evolution of the universe during this period which suggests a connection between the small observed acceleration term and the early inflation of a closed universe. From this we find an unexpected relationship between the O...
0712.1313
Hongbao Zhang
Song He and Hongbao Zhang
The black hole dynamical horizon and generalized second law of thermodynamics
JHEP style, 8 pages, 2 figures, version to appear in JHEP with typos corrected
JHEP0712:052,2007
10.1088/1126-6708/2007/12/052
null
gr-qc astro-ph hep-th
null
The generalized second law of thermodynamics for a system containing a black hole dynamical horizon is proposed in a covariant way. Its validity is also tested in case of adiabatically collapsing thick light shells.
[ { "created": "Sat, 8 Dec 2007 23:16:33 GMT", "version": "v1" }, { "created": "Tue, 11 Dec 2007 16:47:55 GMT", "version": "v2" } ]
2008-11-26
[ [ "He", "Song", "" ], [ "Zhang", "Hongbao", "" ] ]
The generalized second law of thermodynamics for a system containing a black hole dynamical horizon is proposed in a covariant way. Its validity is also tested in case of adiabatically collapsing thick light shells.
1712.05673
Edward Malec
Janusz Karkowski, Wojciech Kulczycki, Patryk Mach, Edward Malec, Andrzej Odrzywolek, Michal Pirog
General-relativistic rotation: self-gravitating fluid tori in motion around black holes
Matches published version
Phys. Rev. D 97, 104034 (2018)
10.1103/PhysRevD.97.104034
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We obtain from the first principles a general-relativistic Keplerian rotation law for self-gravitating disks around spinning black holes. This is an extension of a former rotation law that was designed mainly for toroids around spin-less black holes. We integrate numerically axial stationary Einstein equations with s...
[ { "created": "Fri, 15 Dec 2017 13:50:37 GMT", "version": "v1" }, { "created": "Tue, 13 Mar 2018 12:33:09 GMT", "version": "v2" }, { "created": "Wed, 30 May 2018 12:38:04 GMT", "version": "v3" } ]
2018-06-06
[ [ "Karkowski", "Janusz", "" ], [ "Kulczycki", "Wojciech", "" ], [ "Mach", "Patryk", "" ], [ "Malec", "Edward", "" ], [ "Odrzywolek", "Andrzej", "" ], [ "Pirog", "Michal", "" ] ]
We obtain from the first principles a general-relativistic Keplerian rotation law for self-gravitating disks around spinning black holes. This is an extension of a former rotation law that was designed mainly for toroids around spin-less black holes. We integrate numerically axial stationary Einstein equations with sel...
1210.3022
Naresh Dadhich
Naresh Dadhich
The gravitational equation in higher dimensions
latex, 5pages, Contribution to the Proceedings of the Conference, Relativity and Gravitation: 100 years after Einstein in Prague, June 25-28, 2012
null
null
null
gr-qc astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Like the Lovelock Lagrangian which is a specific homogeneous polynomial in Riemann curvature, for an alternative derivation of the gravitational equation of motion, it is possible to define a specific homogeneous polynomial analogue of the Riemann curvature, and then the trace of its Bianchi derivative yields the cor...
[ { "created": "Wed, 10 Oct 2012 09:32:46 GMT", "version": "v1" } ]
2012-10-12
[ [ "Dadhich", "Naresh", "" ] ]
Like the Lovelock Lagrangian which is a specific homogeneous polynomial in Riemann curvature, for an alternative derivation of the gravitational equation of motion, it is possible to define a specific homogeneous polynomial analogue of the Riemann curvature, and then the trace of its Bianchi derivative yields the corre...
gr-qc/0511031
Fernando Mendez
R. Aloisio, A. Galante, A. Grillo, S. Liberati, E. Luzio and F. Mendez
Deformed Special Relativity as an effective theory of measurements on quantum gravitational backgrounds
11 pages, no figures
Phys.Rev. D73 (2006) 045020
10.1103/PhysRevD.73.045020
null
gr-qc hep-ph hep-th
null
In this article we elaborate on a recently proposed interpretation of DSR as an effective measurement theory in the presence of non-negligible (albeit small) quantum gravitational fluctuations. We provide several heuristic arguments to explain how such a new theory can emerge and discuss the possible observational co...
[ { "created": "Sun, 6 Nov 2005 21:49:20 GMT", "version": "v1" } ]
2009-11-11
[ [ "Aloisio", "R.", "" ], [ "Galante", "A.", "" ], [ "Grillo", "A.", "" ], [ "Liberati", "S.", "" ], [ "Luzio", "E.", "" ], [ "Mendez", "F.", "" ] ]
In this article we elaborate on a recently proposed interpretation of DSR as an effective measurement theory in the presence of non-negligible (albeit small) quantum gravitational fluctuations. We provide several heuristic arguments to explain how such a new theory can emerge and discuss the possible observational cons...
2010.13287
Thae Hyok Kim
Ok Song An, Jin U Kang, Thae Hyok Kim, Ui Ri Mun
Notes on the post-bounce background dynamics in bouncing cosmologies
26 pages, 15 figures. Significantly revised and accepted version for JHEP
null
10.1007/JHEP10(2021)085
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate the post-bounce background dynamics in a certain class of single bounce scenarios studied in the literature, in which the cosmic bounce is driven by a scalar field with negative exponential potential such as the ekpyrotic potential. We show that those models can actually lead to cyclic evolutions with ...
[ { "created": "Mon, 26 Oct 2020 02:28:49 GMT", "version": "v1" }, { "created": "Thu, 16 Sep 2021 06:56:50 GMT", "version": "v2" } ]
2021-10-27
[ [ "An", "Ok Song", "" ], [ "Kang", "Jin U", "" ], [ "Kim", "Thae Hyok", "" ], [ "Mun", "Ui Ri", "" ] ]
We investigate the post-bounce background dynamics in a certain class of single bounce scenarios studied in the literature, in which the cosmic bounce is driven by a scalar field with negative exponential potential such as the ekpyrotic potential. We show that those models can actually lead to cyclic evolutions with re...
2406.10436
Mourad Guenouche
Mourad Guenouche
Effect of the spatial curvature on light bending and time delay in curved Einstein-Straus-de Sitter solution
36 pages, 6 figures, 5 tables
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A method of general applicability has been developed, whereby the null geodesic equations of the Einstein-Straus-de Sitter metric can be integrated simultaneously in terms of the curvature constant $k$. The purpose is to generalize the computation of light deflection and time delay by a spherical mass distribution. A...
[ { "created": "Fri, 14 Jun 2024 22:58:37 GMT", "version": "v1" } ]
2024-06-18
[ [ "Guenouche", "Mourad", "" ] ]
A method of general applicability has been developed, whereby the null geodesic equations of the Einstein-Straus-de Sitter metric can be integrated simultaneously in terms of the curvature constant $k$. The purpose is to generalize the computation of light deflection and time delay by a spherical mass distribution. Ass...
gr-qc/9603056
Takeshi Chiba
Takeshi Chiba, Jiro Soda
Critical Behavior in the Brans-Dicke Theory of Gravitation
6 pages
Prog.Theor.Phys. 96 (1996) 567-574
10.1143/PTP.96.567
KUNS-1386, KUCP-0093
gr-qc
null
The collapse of a massless scalar field in the Brans-Dicke theory of gravitation is studied in the analysis of both analytical solution and numerical one. By conformally transforming the Roberts's solution into the Brans-Dicke frame, we find for $\omega > -3/2$ that a continuous self-similarity continues and that the...
[ { "created": "Thu, 28 Mar 1996 09:21:34 GMT", "version": "v1" } ]
2009-10-28
[ [ "Chiba", "Takeshi", "" ], [ "Soda", "Jiro", "" ] ]
The collapse of a massless scalar field in the Brans-Dicke theory of gravitation is studied in the analysis of both analytical solution and numerical one. By conformally transforming the Roberts's solution into the Brans-Dicke frame, we find for $\omega > -3/2$ that a continuous self-similarity continues and that the c...
gr-qc/9806003
Malcolm MacCallum
M.A.H. MacCallum
Integrability in tetrad formalisms and conservation in cosmology
10 pages, latex 2.09, uses sprocl.sty To appear in the Proceedings of the International Seminar on Mathematical Cosmology, Potsdam, Mar-Apr 98, ed. H.-J. Schmidt and M. Rainer. World Scientific, Singapore
Current Topics in Mathematical Cosmology (Proceedings of the International Seminar), ed. M. Rainer and H.-J. Schmidt, World Scientific (1998)
null
null
gr-qc
null
Integrability in general tetrad formalisms is reviewed, following and clarifying work of Papapetrou and Edgar. The integrability conditions are (combinations of) the Bianchi equations and their consequences. The introduction of additional constraints is considered. Recent results on the conservation of constraints in...
[ { "created": "Sat, 30 May 1998 16:22:00 GMT", "version": "v1" } ]
2008-02-11
[ [ "MacCallum", "M. A. H.", "" ] ]
Integrability in general tetrad formalisms is reviewed, following and clarifying work of Papapetrou and Edgar. The integrability conditions are (combinations of) the Bianchi equations and their consequences. The introduction of additional constraints is considered. Recent results on the conservation of constraints in t...
1505.01680
Dirk Puetzfeld
Yuri N. Obukhov, Dirk Puetzfeld
Multipolar test body equations of motion in generalized gravity theories
54 pages, 3 figures, to appear in "Equations of Motion in Relativistic Gravity", D. Puetzfeld et al. (eds.), Fundamental theories of Physics, Springer 2015. arXiv admin note: substantial text overlap with arXiv:1408.5669
null
10.1007/978-3-319-18335-0_2
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We give an overview of the derivation of multipolar equations of motion of extended test bodies for a wide set of gravitational theories beyond the standard general relativistic framework. The classes of theories covered range from simple generalizations of General Relativity, e.g. encompassing additional scalar fiel...
[ { "created": "Thu, 7 May 2015 12:30:39 GMT", "version": "v1" } ]
2021-04-07
[ [ "Obukhov", "Yuri N.", "" ], [ "Puetzfeld", "Dirk", "" ] ]
We give an overview of the derivation of multipolar equations of motion of extended test bodies for a wide set of gravitational theories beyond the standard general relativistic framework. The classes of theories covered range from simple generalizations of General Relativity, e.g. encompassing additional scalar fields...
2011.08222
Imanol Albarran
Imanol Albarran, Mariam Bouhmadi-L\'opez, Jo\~ao Marto
A varying Dark Energy effective speed of sound parameter in the phantom Universe
15 pages, 6 figures. Improved version with an extended physical discussion. Version published in EPJC
Eur. Phys. J. C 81 (2021) no.9, 803
10.1140/epjc/s10052-021-09546-2
null
gr-qc astro-ph.CO hep-ph
http://creativecommons.org/licenses/by-nc-nd/4.0/
We analyse the phenomenological effects of a varying Dark Energy (DE) effective speed of sound parameter, $c^{2}_{\textrm{sd}}$, on the cosmological perturbations of three phantom DE models. Each of these models induce a particular abrupt future event known as Big Rip (BR), Little Rip (LR), and Little Sibling of the ...
[ { "created": "Mon, 16 Nov 2020 19:09:16 GMT", "version": "v1" }, { "created": "Fri, 5 Nov 2021 12:23:50 GMT", "version": "v2" } ]
2021-11-08
[ [ "Albarran", "Imanol", "" ], [ "Bouhmadi-López", "Mariam", "" ], [ "Marto", "João", "" ] ]
We analyse the phenomenological effects of a varying Dark Energy (DE) effective speed of sound parameter, $c^{2}_{\textrm{sd}}$, on the cosmological perturbations of three phantom DE models. Each of these models induce a particular abrupt future event known as Big Rip (BR), Little Rip (LR), and Little Sibling of the Bi...
0707.0588
Mairi Sakellariadou
William Nelson and Mairi Sakellariadou (King's College, London)
Lattice Refining LQC and the Matter Hamiltonian
15 pages, 3 figures, revtex style; amended version to match publication in Phys. Rev. D
Phys.Rev.D76:104003,2007
10.1103/PhysRevD.76.104003
null
gr-qc astro-ph hep-ex hep-ph hep-th
null
In the context of loop quantum cosmology, we parametrise the lattice refinement by a parameter, $A$, and the matter Hamiltonian by a parameter, $\delta$. We then solve the Hamiltonian constraint for both a self-adjoint, and a non-self-adjoint Hamiltonian operator. Demanding that the solutions for the wave-functions o...
[ { "created": "Wed, 4 Jul 2007 12:11:43 GMT", "version": "v1" }, { "created": "Thu, 30 Aug 2007 11:17:33 GMT", "version": "v2" } ]
2008-11-26
[ [ "Nelson", "William", "", "King's College, London" ], [ "Sakellariadou", "Mairi", "", "King's College, London" ] ]
In the context of loop quantum cosmology, we parametrise the lattice refinement by a parameter, $A$, and the matter Hamiltonian by a parameter, $\delta$. We then solve the Hamiltonian constraint for both a self-adjoint, and a non-self-adjoint Hamiltonian operator. Demanding that the solutions for the wave-functions obe...
2204.06267
Saskia Grunau
Saskia Grunau and Jutta Kunz
Hyperelliptic functions and motion in general relativity
Published in MDPI Mathematics 2022, 10(12), 1958, Special Issue "Partial Differential Equations and Applications". (Changes made as requested by the referees and editors.)
Mathematics 2022, 10(12), 1958
10.3390/math10121958
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Analysis of black hole spacetimes requires study of the motion of particles and light in these spacetimes. Here exact solutions of the geodesic equations are the means of choice. Numerous interesting black hole spacetimes have been analyzed in terms of elliptic functions. However, the presence of a cosmological const...
[ { "created": "Wed, 13 Apr 2022 09:37:46 GMT", "version": "v1" }, { "created": "Mon, 13 Jun 2022 12:10:18 GMT", "version": "v2" } ]
2022-06-14
[ [ "Grunau", "Saskia", "" ], [ "Kunz", "Jutta", "" ] ]
Analysis of black hole spacetimes requires study of the motion of particles and light in these spacetimes. Here exact solutions of the geodesic equations are the means of choice. Numerous interesting black hole spacetimes have been analyzed in terms of elliptic functions. However, the presence of a cosmological constan...
gr-qc/9311023
Andrew Barvinski
A.O.Barvinsky
Tunnelling geometries II. Reduction methods for functional determinants
23 pages, latex, figures are not included (available on request by regular mail), report Alberta Thy-41-93
Phys.Rev. D50 (1994) 5115-5124
10.1103/PhysRevD.50.5115
null
gr-qc
null
The reduction algorithms for functional determinants of differential operators on spacetime manifolds of different topological types are presented, which were recently used for the calculation of the no-boundary wavefunction and the partition function of tunnelling geometries in quantum gravity and cosmology.
[ { "created": "Sun, 14 Nov 1993 04:55:34 GMT", "version": "v1" } ]
2009-10-22
[ [ "Barvinsky", "A. O.", "" ] ]
The reduction algorithms for functional determinants of differential operators on spacetime manifolds of different topological types are presented, which were recently used for the calculation of the no-boundary wavefunction and the partition function of tunnelling geometries in quantum gravity and cosmology.
gr-qc/0209077
Olga V. Babourova
Olga V. Babourova, Boris N. Frolov
Matter with dilaton charge in Weyl-Cartan spacetime and evolution of the Universe
LaTex, 23 pages, no figures, uses IOP.sty, misprints and references corrected
Class.Quant.Grav.20:1423-1442,2003
10.1088/0264-9381/20/8/302
null
gr-qc astro-ph
null
The perfect dilaton-spin fluid (as a model of the dilaton matter, the particles of which are endowed with intrinsic spin and dilaton charge) is considered as the source of the gravitational field in a Weyl-Cartan spacetime. The variational theory of such fluid is constructed and the dilaton-spin fluid energy-momentum...
[ { "created": "Sat, 21 Sep 2002 11:30:07 GMT", "version": "v1" }, { "created": "Thu, 19 Dec 2002 17:51:53 GMT", "version": "v2" } ]
2011-07-19
[ [ "Babourova", "Olga V.", "" ], [ "Frolov", "Boris N.", "" ] ]
The perfect dilaton-spin fluid (as a model of the dilaton matter, the particles of which are endowed with intrinsic spin and dilaton charge) is considered as the source of the gravitational field in a Weyl-Cartan spacetime. The variational theory of such fluid is constructed and the dilaton-spin fluid energy-momentum t...
gr-qc/9501037
Sujan Sengupta
Sujan Sengupta (Indian Institute Of Astrophysics, Bangalore 560034)
TOWARDS A PHYSICAL INTERPRETATION OF THE ANGULAR MOMENTUM PARAMETER ASSOCIATED WITH THE KERR METRIC
9 pages, LATEX, no figure
null
null
IIA-TH/95-4
gr-qc
null
The role of the parameter `$a$' associated with the Kerr metric which represents the angular momentum per unit mass of a rotating massive object has been converted into determining the rotationally induced quadrapole electric field outside a rotating massive object with external dipole magnetic field. A comparison of...
[ { "created": "Fri, 27 Jan 1995 08:38:54 GMT", "version": "v1" } ]
2016-08-31
[ [ "Sengupta", "Sujan", "", "Indian Institute Of Astrophysics, Bangalore 560034" ] ]
The role of the parameter `$a$' associated with the Kerr metric which represents the angular momentum per unit mass of a rotating massive object has been converted into determining the rotationally induced quadrapole electric field outside a rotating massive object with external dipole magnetic field. A comparison of t...
1101.2147
Mauricio Cataldo MC
Mauricio Cataldo, Fabiola Arevalo and Patricio Mella
Interacting Kasner-type cosmologies
Accepted for publication in Astrophysics &Space Science, 8 pages
Astrophys.Space Sci.333:287-293,2011
10.1007/s10509-011-0596-y
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It is well known that Kasner-type cosmologies provide a useful framework for analyzing the three-dimensional anisotropic expansion because of the simplification of the anisotropic dynamics. In this paper relativistic multi-fluid Kasner-type scenarios are studied. We first consider the general case of a superposition ...
[ { "created": "Tue, 11 Jan 2011 15:47:26 GMT", "version": "v1" } ]
2015-03-17
[ [ "Cataldo", "Mauricio", "" ], [ "Arevalo", "Fabiola", "" ], [ "Mella", "Patricio", "" ] ]
It is well known that Kasner-type cosmologies provide a useful framework for analyzing the three-dimensional anisotropic expansion because of the simplification of the anisotropic dynamics. In this paper relativistic multi-fluid Kasner-type scenarios are studied. We first consider the general case of a superposition of...
1703.09149
Alejandro Perez
Alejandro Perez
Black Holes in Loop Quantum Gravity
Typos corrected, references corrected. To appear in Reports on Progress in Physics
null
10.1088/1361-6633/aa7e14
null
gr-qc hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This is a review of the results on black hole physics in the framework of loop quantum gravity. The key feature underlying the results is the discreteness of geometric quantities at the Planck scale predicted by this approach to quantum gravity. Quantum discreteness follows directly from the canonical quantization pr...
[ { "created": "Mon, 27 Mar 2017 15:38:15 GMT", "version": "v1" }, { "created": "Fri, 8 Sep 2017 13:12:36 GMT", "version": "v2" } ]
2017-11-22
[ [ "Perez", "Alejandro", "" ] ]
This is a review of the results on black hole physics in the framework of loop quantum gravity. The key feature underlying the results is the discreteness of geometric quantities at the Planck scale predicted by this approach to quantum gravity. Quantum discreteness follows directly from the canonical quantization pres...
gr-qc/9903054
L. Sriramkumar
L. Sriramkumar and T. Padmanabhan
Probes of the vacuum structure of quantum fields in classical backgrounds
43 pages, LaTeX2e (uses ajour.cls); Discussions added in sections 3.3, 5.2 and 6.2
Int.J.Mod.Phys. D11 (2002) 1-34
10.1142/S0218271802001354
null
gr-qc hep-th
null
We compare the different approaches presently available in literature to probe the vacuum structure of quantum fields in classical electromagnetic and gravitational backgrounds. We compare the results from the Bogolubov transformations and the effective Lagrangian approach with the response of monopole detectors (of ...
[ { "created": "Sun, 14 Mar 1999 17:14:13 GMT", "version": "v1" }, { "created": "Thu, 21 Sep 2000 00:27:19 GMT", "version": "v2" }, { "created": "Fri, 23 Feb 2001 03:02:15 GMT", "version": "v3" } ]
2009-10-31
[ [ "Sriramkumar", "L.", "" ], [ "Padmanabhan", "T.", "" ] ]
We compare the different approaches presently available in literature to probe the vacuum structure of quantum fields in classical electromagnetic and gravitational backgrounds. We compare the results from the Bogolubov transformations and the effective Lagrangian approach with the response of monopole detectors (of th...
1210.3372
Si Chen
Si Chen and Steven S. Plotkin
Statistical mechanics of graph models and their implications for emergent spacetime manifolds
21 pages, 20 figures, 1 table; v2: References added; Figure added; Discussion expanded; v3: minor corrections, published version
Phys. Rev. D 87, 084011 (2013)
10.1103/PhysRevD.87.084011
null
gr-qc cond-mat.dis-nn cond-mat.stat-mech hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Inspired by "quantum graphity" models for spacetime, a statistical model of graphs is proposed to explore possible realizations of emergent manifolds. Graphs with given numbers of vertices and edges are considered, governed by a very general Hamiltonian that merely favors graphs with near-constant valency and local r...
[ { "created": "Thu, 11 Oct 2012 20:50:29 GMT", "version": "v1" }, { "created": "Mon, 18 Feb 2013 00:54:36 GMT", "version": "v2" }, { "created": "Fri, 5 Apr 2013 21:18:35 GMT", "version": "v3" } ]
2013-04-09
[ [ "Chen", "Si", "" ], [ "Plotkin", "Steven S.", "" ] ]
Inspired by "quantum graphity" models for spacetime, a statistical model of graphs is proposed to explore possible realizations of emergent manifolds. Graphs with given numbers of vertices and edges are considered, governed by a very general Hamiltonian that merely favors graphs with near-constant valency and local rot...
gr-qc/0406118
Bahram Mashhoon
C. Chicone and B. Mashhoon
Significance of c/sqrt(2) in Relativistic Physics
7 pages, 1 figure, slightly expanded version accepted for publication in Class. Quantum Grav
Class.Quant.Grav. 21 (2004) L139
10.1088/0264-9381/21/24/L01
null
gr-qc astro-ph
null
In the description of \emph{relative} motion in accelerated systems and gravitational fields, inertial and tidal accelerations must be taken into account, respectively. These involve a critical speed that in the first approximation can be simply illustrated in the case of motion in one dimension. For one-dimensional ...
[ { "created": "Tue, 29 Jun 2004 23:03:15 GMT", "version": "v1" }, { "created": "Thu, 21 Oct 2004 23:48:53 GMT", "version": "v2" } ]
2009-11-10
[ [ "Chicone", "C.", "" ], [ "Mashhoon", "B.", "" ] ]
In the description of \emph{relative} motion in accelerated systems and gravitational fields, inertial and tidal accelerations must be taken into account, respectively. These involve a critical speed that in the first approximation can be simply illustrated in the case of motion in one dimension. For one-dimensional mo...
2212.08865
Jiri Podolsky
Jiri Podolsky, Adam Vratny
New form of all black holes of type D with a cosmological constant
38 pages, 3 figures. arXiv admin note: text overlap with arXiv:2108.02239. Final version accepted for publication in Phys. Rev. D, with corrected electromagnetic field (in agreement with the results presented in Astorino and Boldi, JHEP 08 (2023) 085, arxiv.org/abs/2305.03744)
Phys. Rev. D 107, 084034 (2023)
10.1103/PhysRevD.107.084034
null
gr-qc hep-th
http://creativecommons.org/licenses/by-nc-nd/4.0/
We present an improved metric form of the complete family of exact black hole spacetimes of algebraic type D, including any cosmological constant. This class was found by Debever in 1971, Plebanski and Demianski in 1976, and conveniently reformulated by Griffiths and Podolsky in 2005. In our new form of this metric t...
[ { "created": "Sat, 17 Dec 2022 13:21:33 GMT", "version": "v1" }, { "created": "Fri, 10 Mar 2023 20:40:40 GMT", "version": "v2" }, { "created": "Sun, 26 Nov 2023 13:41:33 GMT", "version": "v3" } ]
2024-07-24
[ [ "Podolsky", "Jiri", "" ], [ "Vratny", "Adam", "" ] ]
We present an improved metric form of the complete family of exact black hole spacetimes of algebraic type D, including any cosmological constant. This class was found by Debever in 1971, Plebanski and Demianski in 1976, and conveniently reformulated by Griffiths and Podolsky in 2005. In our new form of this metric the...
2302.10938
Shahar Hod
Shahar Hod
Comment on: "Possible Relation between the Cosmological Constant and Standard Model Parameters"
2 pages
null
null
null
gr-qc
http://creativecommons.org/licenses/by/4.0/
It has recently been proposed [M. P. Hertzberg and A. Loeb, arXiv:2302.09090] that the observed value of the cosmological constant can be related to the physical parameters of the Standard Model. In the present compact note we point out that the derivation of the claimed cosmological-constant-standard-model relation ...
[ { "created": "Tue, 21 Feb 2023 19:00:08 GMT", "version": "v1" } ]
2023-02-23
[ [ "Hod", "Shahar", "" ] ]
It has recently been proposed [M. P. Hertzberg and A. Loeb, arXiv:2302.09090] that the observed value of the cosmological constant can be related to the physical parameters of the Standard Model. In the present compact note we point out that the derivation of the claimed cosmological-constant-standard-model relation pr...
gr-qc/9912104
Garcia
L.C.Garcia de Andrade
On de Sitter gravitationally from the spin-torsion primordial density
Latex file
null
null
null
gr-qc
null
Fluctuations on de Sitter solution of Einstein-Cartan field equations are obtained in terms of the matter density primordial density fluctuations and spin-torsion density and matter density fluctuations obtained from COBE data. Einstein-de Sitter solution is shown to be unstable even in the absence of torsion.The spi...
[ { "created": "Fri, 24 Dec 1999 09:00:35 GMT", "version": "v1" } ]
2007-05-23
[ [ "de Andrade", "L. C. Garcia", "" ] ]
Fluctuations on de Sitter solution of Einstein-Cartan field equations are obtained in terms of the matter density primordial density fluctuations and spin-torsion density and matter density fluctuations obtained from COBE data. Einstein-de Sitter solution is shown to be unstable even in the absence of torsion.The spin-...
gr-qc/0605026
Tomasz Pawlowski
Jerzy Lewandowski, Tomasz Pawlowski
Symmetric non-expanding horizons
Revtex4, 36 pages
Class.Quant.Grav. 23 (2006) 6031-6058
10.1088/0264-9381/23/20/022
IGPG-06/5-1
gr-qc
null
Symmetric non-expanding horizons are studied in arbitrary dimension. The global properties -as the zeros of infinitesimal symmetries- are analyzed particularly carefully. For the class of NEH geometries admitting helical symmetry a quasi-local analog of Hawking's rigidity theorem is formulated and proved: the presenc...
[ { "created": "Thu, 4 May 2006 15:23:37 GMT", "version": "v1" } ]
2009-11-11
[ [ "Lewandowski", "Jerzy", "" ], [ "Pawlowski", "Tomasz", "" ] ]
Symmetric non-expanding horizons are studied in arbitrary dimension. The global properties -as the zeros of infinitesimal symmetries- are analyzed particularly carefully. For the class of NEH geometries admitting helical symmetry a quasi-local analog of Hawking's rigidity theorem is formulated and proved: the presence ...
2106.09044
Anzhong Wang
Jacob Oost, Shinji Mukohyama, and Anzhong Wang
Spherically symmetric exact vacuum solutions in Einstein-aether theory
revtex4-1, one figure and no tables. Some typos are corrected. Universe 7 (2021) 272
Universe 7 (2021) 272
10.3390/universe7080272
YITP-21-59, IPMU21-0036
gr-qc astro-ph.GA hep-ph hep-th
http://creativecommons.org/licenses/by/4.0/
We study spherically symmetric spacetimes in Einstein-aether theory in three different coordinate systems, the isotropic, Painlev\`e-Gullstrand, and Schwarzschild coordinates, in which the aether is always comoving, and present both time-dependent and time-independent exact vacuum solutions. In particular, in the iso...
[ { "created": "Wed, 16 Jun 2021 18:00:04 GMT", "version": "v1" }, { "created": "Thu, 1 Jul 2021 13:30:58 GMT", "version": "v2" }, { "created": "Thu, 22 Jul 2021 19:44:22 GMT", "version": "v3" }, { "created": "Wed, 28 Jul 2021 20:00:02 GMT", "version": "v4" } ]
2021-07-30
[ [ "Oost", "Jacob", "" ], [ "Mukohyama", "Shinji", "" ], [ "Wang", "Anzhong", "" ] ]
We study spherically symmetric spacetimes in Einstein-aether theory in three different coordinate systems, the isotropic, Painlev\`e-Gullstrand, and Schwarzschild coordinates, in which the aether is always comoving, and present both time-dependent and time-independent exact vacuum solutions. In particular, in the isotr...
gr-qc/0105103
Vitor Cardoso
Vitor Cardoso, Jose' P. S. Lemos
Quasi-Normal Modes of Schwarzschild Anti-De Sitter Black Holes: Electromagnetic and Gravitational Perturbations
2 figures
Phys.Rev. D64 (2001) 084017
10.1103/PhysRevD.64.084017
null
gr-qc hep-th
null
We study the quasi-normal modes (QNM) of electromagnetic and gravitational perturbations of a Schwarzschild black hole in an asymptotically Anti-de Sitter (AdS) spacetime. Some of the electromagnetic modes do not oscillate, they only decay, since they have pure imaginary frequencies. The gravitational modes show pecu...
[ { "created": "Mon, 28 May 2001 19:20:39 GMT", "version": "v1" } ]
2009-11-07
[ [ "Cardoso", "Vitor", "" ], [ "Lemos", "Jose' P. S.", "" ] ]
We study the quasi-normal modes (QNM) of electromagnetic and gravitational perturbations of a Schwarzschild black hole in an asymptotically Anti-de Sitter (AdS) spacetime. Some of the electromagnetic modes do not oscillate, they only decay, since they have pure imaginary frequencies. The gravitational modes show peculi...
1902.04616
Rossella Gamba
Rossella Gamba, Jocelyn S. Read, Leslie E. Wade
The impact of the crust equation of state on the analysis of GW170817
11 pages, 6 figures
Class. Quantum Grav. 37 025008 (2020)
10.1088/1361-6382/ab5ba4
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The detection of GW170817, the first neutron star-neutron star merger observed by Advanced LIGO and Virgo, and its following analyses represent the first contributions of gravitational wave (GW) data to understanding dense matter. Parameterizing the high density section of the equation of state (EOS) of both neutron ...
[ { "created": "Tue, 12 Feb 2019 20:12:23 GMT", "version": "v1" } ]
2021-11-08
[ [ "Gamba", "Rossella", "" ], [ "Read", "Jocelyn S.", "" ], [ "Wade", "Leslie E.", "" ] ]
The detection of GW170817, the first neutron star-neutron star merger observed by Advanced LIGO and Virgo, and its following analyses represent the first contributions of gravitational wave (GW) data to understanding dense matter. Parameterizing the high density section of the equation of state (EOS) of both neutron st...
gr-qc/9605055
Jose Ademir Sales de Lima
J.A.S. Lima (Brown Univ. and Univ. Federal do Rio Grande do Norte, Natal, Brazil)
Thermodynamics of Decaying Vacuum Cosmologies
21 pages, uses LATEX
Phys.Rev. D54 (1996) 2571-2577
10.1103/PhysRevD.54.2571
BROWN-HET-1013
gr-qc
null
The thermodynamic behavior of vacuum decaying cosmologies is investigated within a manifestly covariant formulation. Such a process corresponds to a continuous irreversible energy flow from the vacuum component to the created matter constituents. It is shown that if the specific entropy per particle remains constant ...
[ { "created": "Sun, 26 May 1996 03:05:48 GMT", "version": "v1" } ]
2009-10-28
[ [ "Lima", "J. A. S.", "", "Brown Univ. and Univ. Federal do Rio Grande do Norte,\n Natal, Brazil" ] ]
The thermodynamic behavior of vacuum decaying cosmologies is investigated within a manifestly covariant formulation. Such a process corresponds to a continuous irreversible energy flow from the vacuum component to the created matter constituents. It is shown that if the specific entropy per particle remains constant du...
gr-qc/0012035
Daniele Oriti
Tullio Regge and Ruth M. Williams
Discrete structures in gravity
30 pages, 4 figures
J.Math.Phys.41:3964-3984,2000
10.1063/1.533333
DAMTP-2000-101
gr-qc
null
Discrete approaches to gravity, both classical and quantum, are reviewed briefly, with emphasis on the method using piecewise-linear spaces. Models of 3-dimensional quantum gravity involving 6j-symbols are then described, and progress in generalising these models to four dimensions is discussed, as is the relationshi...
[ { "created": "Sat, 9 Dec 2000 15:10:53 GMT", "version": "v1" } ]
2011-07-19
[ [ "Regge", "Tullio", "" ], [ "Williams", "Ruth M.", "" ] ]
Discrete approaches to gravity, both classical and quantum, are reviewed briefly, with emphasis on the method using piecewise-linear spaces. Models of 3-dimensional quantum gravity involving 6j-symbols are then described, and progress in generalising these models to four dimensions is discussed, as is the relationship ...
2312.00318
Junji Jia
Zonghai Li and Junji Jia
Deflection of charged signals in a dipole magnetic field in Kerr background
10 pages, 1 figure
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper investigates charged particle deflection in a Kerr spacetime background with a dipole magnetic field, focusing on the equatorial plane and employing the weak field approximation. We employ the Jacobi-Randers metric to unify the treatment of the gravitational and electromagnetic effects on charged particles...
[ { "created": "Fri, 1 Dec 2023 03:19:02 GMT", "version": "v1" } ]
2023-12-04
[ [ "Li", "Zonghai", "" ], [ "Jia", "Junji", "" ] ]
This paper investigates charged particle deflection in a Kerr spacetime background with a dipole magnetic field, focusing on the equatorial plane and employing the weak field approximation. We employ the Jacobi-Randers metric to unify the treatment of the gravitational and electromagnetic effects on charged particles. ...
2301.03568
Hannes R\"uter
Hannes R. R\"uter, Violetta Sagun, Wolfgang Tichy, Tim Dietrich
Quasi-equilibrium configurations of binary systems of dark matter admixed neutron stars
13 pages, 11 figures, v2: Added investigation of dependence on dark matter particle mass
null
null
null
gr-qc astro-ph.HE nucl-th
http://creativecommons.org/licenses/by/4.0/
Using an adapted version of the SGRID code, we construct for the first time consistent quasi-equilibrium configurations for a binary system consisting of two neutron stars in which each is admixed with dark matter. The stars are modelled as a system of two non-interacting fluids minimally coupled to gravity. For the ...
[ { "created": "Mon, 9 Jan 2023 18:39:21 GMT", "version": "v1" }, { "created": "Wed, 20 Sep 2023 19:14:39 GMT", "version": "v2" } ]
2023-09-22
[ [ "Rüter", "Hannes R.", "" ], [ "Sagun", "Violetta", "" ], [ "Tichy", "Wolfgang", "" ], [ "Dietrich", "Tim", "" ] ]
Using an adapted version of the SGRID code, we construct for the first time consistent quasi-equilibrium configurations for a binary system consisting of two neutron stars in which each is admixed with dark matter. The stars are modelled as a system of two non-interacting fluids minimally coupled to gravity. For the fl...
1402.5894
Peter Horvathy
C. Duval, G. W. Gibbons, P. A. Horvathy
Conformal Carroll groups and BMS symmetry
10 pages, no figure. Fast Track COmmunication, to appear in Class. Quant. Grav
null
10.1088/0264-9381/31/9/092001
null
gr-qc hep-th math-ph math.MP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Bondi-Metzner-Sachs (BMS) group is shown to be the conformal extension of Levy-Leblond's "Carroll" group. Further extension to the Newman-Unti (NU) group is also discussed in the Carroll framework.
[ { "created": "Mon, 24 Feb 2014 17:10:17 GMT", "version": "v1" }, { "created": "Thu, 3 Apr 2014 08:10:10 GMT", "version": "v2" } ]
2015-06-18
[ [ "Duval", "C.", "" ], [ "Gibbons", "G. W.", "" ], [ "Horvathy", "P. A.", "" ] ]
The Bondi-Metzner-Sachs (BMS) group is shown to be the conformal extension of Levy-Leblond's "Carroll" group. Further extension to the Newman-Unti (NU) group is also discussed in the Carroll framework.
1908.04690
Pedro Ca\~nate Casseres
Pedro Ca\~nate, Nora Breton
New exact traversable wormhole solution to the Einstein-scalar-Gauss-Bonnet Equations coupled to a power-Maxwell electrodynamics
8 pages, 2 figures
Phys. Rev. D 100, 064067 (2019)
10.1103/PhysRevD.100.064067
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a novel, exact, traversable wormhole (T-WH) solution for $(3+1)$-dimensional Einstein-scalar-Gauss-Bonnet theory (EsGB) coupled to a power-Maxwell nonlinear electrodynamics (NLED). The solution is characterized by two parameters, $\mathcal{Q}\!_{\rm e}$ and $\mathcal{Q}\!_{_{ \mathcal{S} }}$, associated re...
[ { "created": "Tue, 13 Aug 2019 14:59:37 GMT", "version": "v1" } ]
2019-10-09
[ [ "Cañate", "Pedro", "" ], [ "Breton", "Nora", "" ] ]
We present a novel, exact, traversable wormhole (T-WH) solution for $(3+1)$-dimensional Einstein-scalar-Gauss-Bonnet theory (EsGB) coupled to a power-Maxwell nonlinear electrodynamics (NLED). The solution is characterized by two parameters, $\mathcal{Q}\!_{\rm e}$ and $\mathcal{Q}\!_{_{ \mathcal{S} }}$, associated resp...
gr-qc/9506048
null
Giampiero Esposito
Asymptotic Heat Kernels in Quantum Field Theory
15 pages, plain-tex, appearing in Problems on High Energy Physics and Field Theory, Proceedings of the XVII Workshop, Dedicated to the 140th Anniversary of Henri Poincare, pp. 127-134 (Protvino: IHEP Pub. 1995)
null
null
DSF preprint 95/29
gr-qc
null
Asymptotic expansions were first introduced by Henri Poincare in 1886. This paper describes their application to the semi-classical evaluation of amplitudes in quantum field theory with boundaries. By using zeta-function regularization, the conformal anomaly for a massless spin-${1\over 2}$ field in flat Euclidean ba...
[ { "created": "Fri, 23 Jun 1995 06:38:23 GMT", "version": "v1" } ]
2007-05-23
[ [ "Esposito", "Giampiero", "" ] ]
Asymptotic expansions were first introduced by Henri Poincare in 1886. This paper describes their application to the semi-classical evaluation of amplitudes in quantum field theory with boundaries. By using zeta-function regularization, the conformal anomaly for a massless spin-${1\over 2}$ field in flat Euclidean back...
2111.06421
Saeed Noori Gashti
S. Noori Gashti
Two-Field Inflationary Model and Swampland de Sitter Conjecture
11 page. 5 figure, Accepted for publication in Journal of Holography Applications in Physics
Journal of Holography Applications in Physics 2 (1), 13-24 (2022)
10.22128/JHAP.2021.452.1002
null
gr-qc
http://creativecommons.org/licenses/by/4.0/
In this paper, we are going to investigate a new perspective of the two-field inflation model with respect to the swampland dS conjecture. At the first step, we study the two-fields inflation model, and apply the swampland conjecture to our model. Then, we calculate some cosmological parameters such as scalar spectru...
[ { "created": "Thu, 11 Nov 2021 19:06:25 GMT", "version": "v1" } ]
2023-02-14
[ [ "Gashti", "S. Noori", "" ] ]
In this paper, we are going to investigate a new perspective of the two-field inflation model with respect to the swampland dS conjecture. At the first step, we study the two-fields inflation model, and apply the swampland conjecture to our model. Then, we calculate some cosmological parameters such as scalar spectrum ...
1204.4344
Alejandro Perez
Amit Ghosh and Alejandro Perez
Reply to the comment on "Black hole entropy and isolated horizons thermodynamics"
null
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The comment arXiv:1204.2729v1 is completely wrong. The author makes serious mistakes in calculations and judgement. The errors are made at the level of basic undergraduate statistical mechanics.
[ { "created": "Thu, 19 Apr 2012 13:13:39 GMT", "version": "v1" } ]
2012-04-20
[ [ "Ghosh", "Amit", "" ], [ "Perez", "Alejandro", "" ] ]
The comment arXiv:1204.2729v1 is completely wrong. The author makes serious mistakes in calculations and judgement. The errors are made at the level of basic undergraduate statistical mechanics.
2101.01374
Haoran Zhang
Hao-Ran Zhang, Peng-Zhang He, Lei-Shao, Yuan Chen, and Xian-Ru Hu
Shadow of topologically charged rotating braneworld black hole
null
null
10.1142/S0217732322501450
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we discuss optical properties of the topologically charged rotating black hole. We study the horizon, the photon region, the shadow of the black hole and other observables. The results show that in addition to the black hole spin parameter $a$, the other two parameters, tidal charge $\beta$ and electri...
[ { "created": "Tue, 5 Jan 2021 06:55:55 GMT", "version": "v1" }, { "created": "Sun, 21 Mar 2021 17:53:41 GMT", "version": "v2" } ]
2022-11-09
[ [ "Zhang", "Hao-Ran", "" ], [ "He", "Peng-Zhang", "" ], [ "Lei-Shao", "", "" ], [ "Chen", "Yuan", "" ], [ "Hu", "Xian-Ru", "" ] ]
In this paper, we discuss optical properties of the topologically charged rotating black hole. We study the horizon, the photon region, the shadow of the black hole and other observables. The results show that in addition to the black hole spin parameter $a$, the other two parameters, tidal charge $\beta$ and electric ...
1005.5491
Abhay Ashtekar
Abhay Ashtekar
The Big Bang and the Quantum
18 pages, 6 figures. Plenary talk at the Invisible Universe conference held in Paris in July 2009. To appear in the Proceedings, edited by J. M. Alimi et al (AIP Publications)
AIP Conf.Proc.1241:109-121,2010
10.1063/1.3462605
null
gr-qc astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This short review is addressed to cosmologists. General relativity predicts that space-time comes to an end and physics comes to a halt at the big-bang. Recent developments in loop quantum cosmology have shown that these predictions cannot be trusted. Quantum geometry effects can resolve singularities, thereby open...
[ { "created": "Sat, 29 May 2010 23:02:55 GMT", "version": "v1" } ]
2011-01-25
[ [ "Ashtekar", "Abhay", "" ] ]
This short review is addressed to cosmologists. General relativity predicts that space-time comes to an end and physics comes to a halt at the big-bang. Recent developments in loop quantum cosmology have shown that these predictions cannot be trusted. Quantum geometry effects can resolve singularities, thereby opening ...
gr-qc/9510016
Moretti Walter
Valter Moretti (Dept. Phys. Uni. Trento, Italy)
Hessling's Quantum Equivalence Principle and the Temperature of an Extremal Reissner-Nordstr\"{o}m Black Hole
8 pages, standard LaTex, no figures
null
null
preprint - UTF 363
gr-qc hep-th
null
The Hessling improvement of the Haag, Narnhofer and Stein principle is analysed in the case of a massless scalar field propagating outside of an extremal R-N black hole. It is found that this sort of ``Quantum (Einstein's) Equivalence Principle'' selects only the R-N vacuum as a physically sensible state, i.e., it se...
[ { "created": "Tue, 10 Oct 1995 12:38:48 GMT", "version": "v1" } ]
2007-05-23
[ [ "Moretti", "Valter", "", "Dept. Phys. Uni. Trento, Italy" ] ]
The Hessling improvement of the Haag, Narnhofer and Stein principle is analysed in the case of a massless scalar field propagating outside of an extremal R-N black hole. It is found that this sort of ``Quantum (Einstein's) Equivalence Principle'' selects only the R-N vacuum as a physically sensible state, i.e., it sele...
gr-qc/0309113
Zuxiang Dai
Zuxiang Dai
Cosmological magnetic fields: generation during inflation and evolution
43 pages, paper also at http://www.slac.stanford.edu/spires/find/hep/www?irn=5513243
null
null
null
gr-qc
null
This paper concerns the generation and evolution of the cosmological (large-scale $\sim Mpc$) magnetic fields in an inflationary universe. The universe during inflation is represented by de Sitter space-time. We started with the Maxwell equations in spatially flat Friedmann-Robertson-Walker (FRW) Cosmologies. Then we...
[ { "created": "Tue, 23 Sep 2003 15:27:49 GMT", "version": "v1" } ]
2007-05-23
[ [ "Dai", "Zuxiang", "" ] ]
This paper concerns the generation and evolution of the cosmological (large-scale $\sim Mpc$) magnetic fields in an inflationary universe. The universe during inflation is represented by de Sitter space-time. We started with the Maxwell equations in spatially flat Friedmann-Robertson-Walker (FRW) Cosmologies. Then we c...
2206.13227
Arnau Mas
Jordi Gaset, Arnau Mas
A variational derivation of the field equations of an action-dependent Einstein-Hilbert Lagrangian
22 pp; v1: initial submission; v2: minor changes; v3: submitted to Journal of Geometric Mechanics, updated to reflect changes after peer review
null
10.3934/jgm.2023014
null
gr-qc math-ph math.MP physics.class-ph
http://creativecommons.org/licenses/by/4.0/
We derive the equations of motion of an action-dependent version of the Einstein-Hilbert Lagrangian, as a specific instance of the Herglotz variational problem. Action-dependent Lagrangians lead to dissipative dynamics, which cannot be obtained with the standard method of Lagrangian field theory. First-order theories...
[ { "created": "Thu, 23 Jun 2022 20:56:28 GMT", "version": "v1" }, { "created": "Thu, 7 Jul 2022 11:53:05 GMT", "version": "v2" }, { "created": "Mon, 30 Jan 2023 16:44:44 GMT", "version": "v3" } ]
2023-03-08
[ [ "Gaset", "Jordi", "" ], [ "Mas", "Arnau", "" ] ]
We derive the equations of motion of an action-dependent version of the Einstein-Hilbert Lagrangian, as a specific instance of the Herglotz variational problem. Action-dependent Lagrangians lead to dissipative dynamics, which cannot be obtained with the standard method of Lagrangian field theory. First-order theories o...
1710.01822
Ivan Gentile De Austria
Ivan Gentile de Austria
Bounds for the metric and shift vector on extreme Kerr under linear axially symmetric gravitational perturbations
14 pages
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present integral estimates for the shift and induced metric in the maximal isothermal gauge, corresponding to linear axially symmetric gravitational perturbations over the Minkowski and extreme Kerr metric. These bounds are a step towards finding pointwise bounds for the perturbations. In particular the presented ...
[ { "created": "Wed, 4 Oct 2017 22:59:01 GMT", "version": "v1" } ]
2017-10-06
[ [ "de Austria", "Ivan Gentile", "" ] ]
We present integral estimates for the shift and induced metric in the maximal isothermal gauge, corresponding to linear axially symmetric gravitational perturbations over the Minkowski and extreme Kerr metric. These bounds are a step towards finding pointwise bounds for the perturbations. In particular the presented es...
gr-qc/9810041
Korotkin Dmitrii
D.Korotkin and V.Matveev
Solutions of Schlesinger system and Ernst equation in terms of theta-functions
null
null
null
AEI-087, august 1998
gr-qc
null
We discuss the relationship between Schlesinger system and stationary axisymmetric Einstein's equation on the level of algebro-geometric solutions. In particular, we calculate all metric coefficients corresponding to solutions of Ernst equation in terms of theta-functions.
[ { "created": "Mon, 12 Oct 1998 09:58:00 GMT", "version": "v1" } ]
2007-05-23
[ [ "Korotkin", "D.", "" ], [ "Matveev", "V.", "" ] ]
We discuss the relationship between Schlesinger system and stationary axisymmetric Einstein's equation on the level of algebro-geometric solutions. In particular, we calculate all metric coefficients corresponding to solutions of Ernst equation in terms of theta-functions.
gr-qc/9306020
null
Gerhard Rein, Alan D. Rendall, and Jack Schaeffer
A regularity theorem for solutions of the spherically symmetric Vlasov-Einstein system
15 pages, Latex, report # 2
Commun.Math.Phys. 168 (1995) 467-478
10.1007/BF02101839
null
gr-qc
null
In a previous paper two of the authors (G. R. and A. D. R.) showed that there exist global, classical solutions of the spherically symmetric Vlasov-Einstein system for small initial data. The present paper continues this investigation and allows also large initial data. It is shown that if a solution of the spherical...
[ { "created": "Wed, 16 Jun 1993 09:18:47 GMT", "version": "v1" } ]
2015-06-25
[ [ "Rein", "Gerhard", "" ], [ "Rendall", "Alan D.", "" ], [ "Schaeffer", "Jack", "" ] ]
In a previous paper two of the authors (G. R. and A. D. R.) showed that there exist global, classical solutions of the spherically symmetric Vlasov-Einstein system for small initial data. The present paper continues this investigation and allows also large initial data. It is shown that if a solution of the spherically...
gr-qc/9305007
Don N. Page
Don N. Page
Average Entropy of a Subsystem
10 pages, LaTeX. Title change and minor corrections added before publication in Phys. Rev. Lett. 71 (1993) 1291. Alberta-Thy-22-93
Phys.Rev.Lett.71:1291-1294,1993
10.1103/PhysRevLett.71.1291
null
gr-qc hep-th
null
If a quantum system of Hilbert space dimension $mn$ is in a random pure state, the average entropy of a subsystem of dimension $m\leq n$ is conjectured to be $S_{m,n}=\sum_{k=n+1}^{mn}\frac{1}{k}-\frac{m-1}{2n}$ and is shown to be $\simeq \ln m - \frac{m}{2n}$ for $1\ll m\leq n$. Thus there is less than one-half unit...
[ { "created": "Fri, 7 May 1993 17:14:41 GMT", "version": "v1" }, { "created": "Tue, 31 Aug 1993 23:23:25 GMT", "version": "v2" } ]
2014-11-17
[ [ "Page", "Don N.", "" ] ]
If a quantum system of Hilbert space dimension $mn$ is in a random pure state, the average entropy of a subsystem of dimension $m\leq n$ is conjectured to be $S_{m,n}=\sum_{k=n+1}^{mn}\frac{1}{k}-\frac{m-1}{2n}$ and is shown to be $\simeq \ln m - \frac{m}{2n}$ for $1\ll m\leq n$. Thus there is less than one-half unit o...
1501.04773
Francisco Lobo
Mohammad Reza Mehdizadeh, Mahdi Kord Zangeneh, Francisco S. N. Lobo
Einstein-Gauss-Bonnet traversable wormholes satisfying the weak energy condition
8 pages, 6 figures. V2: 9 pages, minor modifications, references added and typo corrected; to appear in PRD
Phys.Rev.D91:084004,2015
10.1103/PhysRevD.91.084004
null
gr-qc astro-ph.HE hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we explore higher-dimensional asymptotically flat wormhole geometries in the framework of Gauss-Bonnet (GB) gravity and investigate the effects of the GB term, by considering a specific radial-dependent redshift function and by imposing a particular equation of state. This work is motivated by previous...
[ { "created": "Tue, 20 Jan 2015 12:14:31 GMT", "version": "v1" }, { "created": "Mon, 16 Mar 2015 19:32:17 GMT", "version": "v2" } ]
2015-04-06
[ [ "Mehdizadeh", "Mohammad Reza", "" ], [ "Zangeneh", "Mahdi Kord", "" ], [ "Lobo", "Francisco S. N.", "" ] ]
In this paper, we explore higher-dimensional asymptotically flat wormhole geometries in the framework of Gauss-Bonnet (GB) gravity and investigate the effects of the GB term, by considering a specific radial-dependent redshift function and by imposing a particular equation of state. This work is motivated by previous a...
1903.01726
Tomas Ledvinka
Tom\'a\v{s} Ledvinka and Ji\v{r}\'i Bi\v{c}\'ak
Disk sources of the Kerr and Tomimatsu-Sato spacetimes: construction and physical properties
null
null
10.1103/PhysRevD.99.064046
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We construct the disk sources matched to the exact vacuum Kerr and to the two classes of Tomimatsu-Sato spacetimes. We analyze two models of the matter forming these disks. At each radius we consider either a rotating massive ring with pressure or two counter-rotating streams of particles in circular geodesic motion....
[ { "created": "Tue, 5 Mar 2019 08:46:07 GMT", "version": "v1" } ]
2019-04-17
[ [ "Ledvinka", "Tomáš", "" ], [ "Bičák", "Jiří", "" ] ]
We construct the disk sources matched to the exact vacuum Kerr and to the two classes of Tomimatsu-Sato spacetimes. We analyze two models of the matter forming these disks. At each radius we consider either a rotating massive ring with pressure or two counter-rotating streams of particles in circular geodesic motion. D...
1309.6622
Seyed Meraj Mousavi Rasouli
S. M. M. Rasouli, A. H. Ziaie, J. Marto and P. V. Moniz
Gravitational Collapse of a Homogeneous Scalar Field in Deformed Phase Space
17 pages, 17 figures
Phys. Rev. D 89, 044028 (2014)
10.1103/PhysRevD.89.044028
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the gravitational collapse of a homogeneous scalar field, minimally coupled to gravity, in the presence of a particular type of dynamical deformation between the canonical momenta of the scale factor and of the scalar field. In the absence of such a deformation, a class of solutions can be found in the liter...
[ { "created": "Wed, 25 Sep 2013 19:44:41 GMT", "version": "v1" }, { "created": "Tue, 4 Mar 2014 00:21:55 GMT", "version": "v2" } ]
2014-03-05
[ [ "Rasouli", "S. M. M.", "" ], [ "Ziaie", "A. H.", "" ], [ "Marto", "J.", "" ], [ "Moniz", "P. V.", "" ] ]
We study the gravitational collapse of a homogeneous scalar field, minimally coupled to gravity, in the presence of a particular type of dynamical deformation between the canonical momenta of the scale factor and of the scalar field. In the absence of such a deformation, a class of solutions can be found in the literat...
2007.02409
Mushtaq Ahmad Sial
G. Mustafa, M. Farasat Shamir, Mushtaq Ahmad
Bardeen Stellar Structures with Karmarkar Condition
23 pages, 17 figures
Phys. Dark Universe 30, 100652 (2020)
10.1016/j.dark.2020.100652
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Current study is focussed to discuss the existence of a new family of compact star solutions by adopting the Karmarkar condition in the background of Bardeen black hole geometry. For this purpose, we consider static spherically symmetric spacetime with anisotropic fluid distribution in the presence of electric charge...
[ { "created": "Sun, 5 Jul 2020 18:26:08 GMT", "version": "v1" } ]
2020-07-07
[ [ "Mustafa", "G.", "" ], [ "Shamir", "M. Farasat", "" ], [ "Ahmad", "Mushtaq", "" ] ]
Current study is focussed to discuss the existence of a new family of compact star solutions by adopting the Karmarkar condition in the background of Bardeen black hole geometry. For this purpose, we consider static spherically symmetric spacetime with anisotropic fluid distribution in the presence of electric charge. ...
1801.08944
Jose Natario
Jo\~ao L. Costa, Jos\'e Nat\'ario, Pedro Oliveira
Decay of solutions of the wave equation in expanding cosmological spacetimes
25 pages, 3 figures; v2: small corrections; v3: typos corrected, matches final published version; v4: typo in the statement of Theorem 2 corrected; v5: sign error in the conformally invariant wave equation fixed
J. Hyperbolic Differ. Equ. 16 (2019) 35-58
10.1142/S0219891619500024
null
gr-qc math.AP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the decay of solutions of the wave equation in some expanding cosmological spacetimes, namely flat Friedmann-Lema\^itre-Robertson-Walker (FLRW) models and the cosmological region of the Reissner-Nordstr\"om-de Sitter (RNdS) solution. By introducing a partial energy and using an iteration scheme, we find that...
[ { "created": "Fri, 26 Jan 2018 19:00:08 GMT", "version": "v1" }, { "created": "Mon, 12 Nov 2018 17:11:00 GMT", "version": "v2" }, { "created": "Wed, 3 Jul 2019 13:13:28 GMT", "version": "v3" }, { "created": "Mon, 22 Jul 2019 10:55:39 GMT", "version": "v4" }, { "cr...
2020-05-06
[ [ "Costa", "João L.", "" ], [ "Natário", "José", "" ], [ "Oliveira", "Pedro", "" ] ]
We study the decay of solutions of the wave equation in some expanding cosmological spacetimes, namely flat Friedmann-Lema\^itre-Robertson-Walker (FLRW) models and the cosmological region of the Reissner-Nordstr\"om-de Sitter (RNdS) solution. By introducing a partial energy and using an iteration scheme, we find that, ...
gr-qc/9208010
Kiyoshi Kamimura
K.Kamimura and T.Fukuyama
Massive Analogue of Ashtekar-CJD Action
6p. Tex
null
10.1016/0083-6656(93)90105-S
TOHO-FP-9243
gr-qc hep-th
null
The action of Ashtekar gravity have been found by Cappovilla, Jacobson and Dell. It does not depend on the metric nor the signature of the space-time. The action has a similar structure as that of a massless relativistic particle. The former is naturally generalized by adding a term analogous to a mass term of the re...
[ { "created": "Tue, 25 Aug 1992 02:25:20 GMT", "version": "v1" } ]
2009-10-22
[ [ "Kamimura", "K.", "" ], [ "Fukuyama", "T.", "" ] ]
The action of Ashtekar gravity have been found by Cappovilla, Jacobson and Dell. It does not depend on the metric nor the signature of the space-time. The action has a similar structure as that of a massless relativistic particle. The former is naturally generalized by adding a term analogous to a mass term of the rela...
1810.12336
K\'evin Nguyen
Oleg Evnin and K\'evin Nguyen
A Graceful Exit for the Cosmological Constant Damping Scenario
v2: 16 pages, minor improvements, discussion added, typos corrected
Phys. Rev. D 98, 124031 (2018)
10.1103/PhysRevD.98.124031
null
gr-qc hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a broad and simple class of scalar-tensor scenarios that successfully realize dynamical damping of the effective cosmological constant, therefore providing a viable dynamical solution to the fine-tuning or "old" cosmological constant problem. In contrast to early versions of this approach, pioneered in the...
[ { "created": "Mon, 29 Oct 2018 18:19:12 GMT", "version": "v1" }, { "created": "Mon, 26 Nov 2018 09:04:45 GMT", "version": "v2" } ]
2018-12-27
[ [ "Evnin", "Oleg", "" ], [ "Nguyen", "Kévin", "" ] ]
We present a broad and simple class of scalar-tensor scenarios that successfully realize dynamical damping of the effective cosmological constant, therefore providing a viable dynamical solution to the fine-tuning or "old" cosmological constant problem. In contrast to early versions of this approach, pioneered in the w...
1202.4639
Thomas W. Baumgarte
Thomas W. Baumgarte
An alternative approach to solving the Hamiltonian constraint
5 pages, 4 figures, matches version published in PRD
Phys.Rev.D85:084013,2012
10.1103/PhysRevD.85.084013
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Solving Einstein's constraint equations for the construction of black hole initial data requires handling the black hole singularity. Typically, this is done either with the excision method, in which the black hole interior is excised from the numerical grid, or with the puncture method, in which the singular part of...
[ { "created": "Tue, 21 Feb 2012 13:52:41 GMT", "version": "v1" }, { "created": "Tue, 24 Apr 2012 12:45:53 GMT", "version": "v2" } ]
2015-06-04
[ [ "Baumgarte", "Thomas W.", "" ] ]
Solving Einstein's constraint equations for the construction of black hole initial data requires handling the black hole singularity. Typically, this is done either with the excision method, in which the black hole interior is excised from the numerical grid, or with the puncture method, in which the singular part of t...
1311.0268
N\'estor Ortiz
N\'estor Ortiz and Olivier Sarbach
Cauchy horizon stability in a collapsing spherical dust cloud I: geometric optic approximation and spherically symmetric test fields
15 pages, 7 figures
Class.Quant.Grav. 31 (2014) 075003
10.1088/0264-9381/31/7/075003
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A spherical dust cloud which is initially at rest and which has a monotonously decaying density profile collapses and forms a shell-focussing singularity. Provided the density profile is not too flat, meaning that its second radial derivative is negative at the center, this singularity is visible to local, and someti...
[ { "created": "Fri, 1 Nov 2013 19:30:11 GMT", "version": "v1" } ]
2014-06-17
[ [ "Ortiz", "Néstor", "" ], [ "Sarbach", "Olivier", "" ] ]
A spherical dust cloud which is initially at rest and which has a monotonously decaying density profile collapses and forms a shell-focussing singularity. Provided the density profile is not too flat, meaning that its second radial derivative is negative at the center, this singularity is visible to local, and sometime...
gr-qc/9906078
Alejandro Corichi
Alejandro Corichi and Andres Gomberoff
On a spacetime duality in 2+1 gravity
23 pages, 2 figures, Revtex file
Class.Quant.Grav. 16 (1999) 3579-3598
10.1088/0264-9381/16/11/309
NSF-ITP-99-061, SU-GP-99/6-1
gr-qc hep-th math-ph math.MP
null
We consider 2+1 dimensional gravity with a cosmological constant, and explore a duality that exists between space-times that have the De Sitter group SO(3,1) as its local isometry group. In particular, the Lorentzian theory with a positive cosmological constant is dual to the Euclidean theory with a negative cosmolog...
[ { "created": "Thu, 17 Jun 1999 23:06:13 GMT", "version": "v1" }, { "created": "Tue, 19 Oct 1999 16:22:21 GMT", "version": "v2" } ]
2009-10-31
[ [ "Corichi", "Alejandro", "" ], [ "Gomberoff", "Andres", "" ] ]
We consider 2+1 dimensional gravity with a cosmological constant, and explore a duality that exists between space-times that have the De Sitter group SO(3,1) as its local isometry group. In particular, the Lorentzian theory with a positive cosmological constant is dual to the Euclidean theory with a negative cosmologic...
gr-qc/0408048
Guoying Chee
G. Y. Chee
Self-dual teleparallel gravity and the positive energy theorem
11 pages, no figure
null
null
null
gr-qc
null
A self-dual and anti-self-dual decomposition of the teleparallel gravity is carried out and the self-dual Lagrangian of the teleparallel gravity which is equivalent to the Ashtekar Lagrangian in vacuum is obtained. Its Hamiltonian formulation and the constraint analysis are developed. Starting from Witten's equation ...
[ { "created": "Mon, 16 Aug 2004 16:20:52 GMT", "version": "v1" } ]
2007-05-23
[ [ "Chee", "G. Y.", "" ] ]
A self-dual and anti-self-dual decomposition of the teleparallel gravity is carried out and the self-dual Lagrangian of the teleparallel gravity which is equivalent to the Ashtekar Lagrangian in vacuum is obtained. Its Hamiltonian formulation and the constraint analysis are developed. Starting from Witten's equation Ne...
2405.09271
Bobby Eka Gunara
Golfin Ekatria, Andy Octavian Latief, Fiki Taufik Akbar, and Bobby Eka Gunara
Gravitational Collapse in Higher-Dimensional Rastall Gravity with and without Cosmological Constant
13 pages, 6 figures, comments are welcome
null
null
null
gr-qc hep-th
http://creativecommons.org/licenses/by/4.0/
We consider a spherically symmetric homogeneous perfect fluid undergoing a gravitational collapse to singularity in the framework of higher-dimensional Rastall gravity in the cases of vanishing and nonvanishing cosmological constants. The possible final states of the collapse in any finite dimension are black hole an...
[ { "created": "Wed, 15 May 2024 11:40:02 GMT", "version": "v1" } ]
2024-05-16
[ [ "Ekatria", "Golfin", "" ], [ "Latief", "Andy Octavian", "" ], [ "Akbar", "Fiki Taufik", "" ], [ "Gunara", "Bobby Eka", "" ] ]
We consider a spherically symmetric homogeneous perfect fluid undergoing a gravitational collapse to singularity in the framework of higher-dimensional Rastall gravity in the cases of vanishing and nonvanishing cosmological constants. The possible final states of the collapse in any finite dimension are black hole and ...
gr-qc/0303104
Roberto Gomez
Roberto Gomez (Pittsburgh Supercomputing Center) and Simonetta Frittelli (Duquesne University)
First-order quasilinear canonical representation of the characteristic formulation of the Einstein equations
revtex4, 7 pages, text and references added, typos corrected, to appear in Phys. Rev. D
Phys.Rev.D68:084013,2003
10.1103/PhysRevD.68.084013
NSF-KITP-03-58
gr-qc
null
We prescribe a choice of 18 variables in all that casts the equations of the fully nonlinear characteristic formulation of general relativity in first--order quasi-linear canonical form. At the analytical level, a formulation of this type allows us to make concrete statements about existence of solutions. In addition...
[ { "created": "Wed, 26 Mar 2003 15:12:19 GMT", "version": "v1" }, { "created": "Tue, 19 Aug 2003 17:33:17 GMT", "version": "v2" } ]
2011-07-19
[ [ "Gomez", "Roberto", "", "Pittsburgh Supercomputing Center" ], [ "Frittelli", "Simonetta", "", "Duquesne University" ] ]
We prescribe a choice of 18 variables in all that casts the equations of the fully nonlinear characteristic formulation of general relativity in first--order quasi-linear canonical form. At the analytical level, a formulation of this type allows us to make concrete statements about existence of solutions. In addition, ...
2107.02077
Mitja Fridman Mr.
Saurya Das, Mitja Fridman, Gaetano Lambiase and Elias C. Vagenas
Baryon Asymmetry from the Generalized Uncertainty Principle
13 pages, 0 figures
Phys. Lett. B 824, 136841 (2022)
10.1016/j.physletb.2021.136841
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The unexplained observed baryon asymmetry in the Universe is a long-standing problem in physics, with no satisfactory resolution so far. To explain this asymmetry, three Sakharov conditions must be met. An interaction term which couples space-time and the baryon current is considered, which satisfies the first two Sa...
[ { "created": "Mon, 5 Jul 2021 15:17:19 GMT", "version": "v1" }, { "created": "Mon, 1 Nov 2021 14:29:35 GMT", "version": "v2" } ]
2022-08-16
[ [ "Das", "Saurya", "" ], [ "Fridman", "Mitja", "" ], [ "Lambiase", "Gaetano", "" ], [ "Vagenas", "Elias C.", "" ] ]
The unexplained observed baryon asymmetry in the Universe is a long-standing problem in physics, with no satisfactory resolution so far. To explain this asymmetry, three Sakharov conditions must be met. An interaction term which couples space-time and the baryon current is considered, which satisfies the first two Sakh...
1512.06829
Neil J. Cornish
Neil J. Cornish and Laura M. Sampson
Towards Robust Gravitational Wave Detection with Pulsar Timing Arrays
11 pages, 12 figures
Phys. Rev. D 93, 104047 (2016)
10.1103/PhysRevD.93.104047
null
gr-qc astro-ph.IM
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Precision timing of highly stable milli-second pulsars is a promising technique for the detection of very low frequency sources of gravitational waves. In any single pulsar, a stochastic gravitational wave signal appears as an additional source of timing noise that can be absorbed by the noise model, and so it is onl...
[ { "created": "Mon, 21 Dec 2015 20:54:18 GMT", "version": "v1" } ]
2016-06-01
[ [ "Cornish", "Neil J.", "" ], [ "Sampson", "Laura M.", "" ] ]
Precision timing of highly stable milli-second pulsars is a promising technique for the detection of very low frequency sources of gravitational waves. In any single pulsar, a stochastic gravitational wave signal appears as an additional source of timing noise that can be absorbed by the noise model, and so it is only ...
gr-qc/0006041
Santiago Esteban Perez Bergliaffa
S. E. Perez Bergliaffa and K. E. Hibberd
On the stress-energy tensor of a rotating wormhole
4 pages, LaTex. Revised version, with several changes
null
null
null
gr-qc
null
We analyze the stress-energy tensor necessary to generate a general stationary and axisymmetric spacetime. The constraints on the geometry arising from considering a perfect fluid as a source are derived. For a fluid with a nonzero stress tensor, we obtain two necessary conditions on the metric. As an example, we sho...
[ { "created": "Mon, 12 Jun 2000 14:40:22 GMT", "version": "v1" }, { "created": "Wed, 26 Jul 2000 16:08:19 GMT", "version": "v2" } ]
2007-05-23
[ [ "Bergliaffa", "S. E. Perez", "" ], [ "Hibberd", "K. E.", "" ] ]
We analyze the stress-energy tensor necessary to generate a general stationary and axisymmetric spacetime. The constraints on the geometry arising from considering a perfect fluid as a source are derived. For a fluid with a nonzero stress tensor, we obtain two necessary conditions on the metric. As an example, we show ...
1810.01286
Muhammad Sharif
M. Sharif and Sara Ashraf
Thermodynamics of Modified Cosmic Chaplygin Gas
16 pages, 6 figures, to appear in AHEP
Ad. High Energy Phys. 2018(2018)8949252
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we examine the thermodynamic features of an exotic fluid known as modified cosmic Chaplygin gas in the context of homogeneous isotropic universe model. For this purpose, the behavior of physical parameters are discussed that help to analyze nature of the universe. Using specific heat formalism, the val...
[ { "created": "Mon, 1 Oct 2018 09:18:43 GMT", "version": "v1" } ]
2018-10-05
[ [ "Sharif", "M.", "" ], [ "Ashraf", "Sara", "" ] ]
In this paper, we examine the thermodynamic features of an exotic fluid known as modified cosmic Chaplygin gas in the context of homogeneous isotropic universe model. For this purpose, the behavior of physical parameters are discussed that help to analyze nature of the universe. Using specific heat formalism, the valid...
1410.5276
Hanno Sahlmann
Jerzy Lewandowski and Hanno Sahlmann
A symmetric scalar constraint for loop quantum gravity
10 pages, v2: added some references and explanations. This version is identical to the published one up to cosmetics
Phys. Rev. D 91, 044022 (2015)
10.1103/PhysRevD.91.044022
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In the framework of loop quantum gravity, we define a new Hilbert space of states which are solutions of a large number of components of the diffeomorphism constraint. On this Hilbert space, using the methods of Thiemann, we obtain a family of gravitational scalar constraints. They preserve the Hilbert space for ever...
[ { "created": "Mon, 20 Oct 2014 13:56:16 GMT", "version": "v1" }, { "created": "Tue, 10 Feb 2015 07:49:07 GMT", "version": "v2" } ]
2015-03-05
[ [ "Lewandowski", "Jerzy", "" ], [ "Sahlmann", "Hanno", "" ] ]
In the framework of loop quantum gravity, we define a new Hilbert space of states which are solutions of a large number of components of the diffeomorphism constraint. On this Hilbert space, using the methods of Thiemann, we obtain a family of gravitational scalar constraints. They preserve the Hilbert space for every ...
gr-qc/0006076
Remo Garattini
Remo Garattini
Casimir energy and variational methods in AdS spacetime
Submitted to Classical and Quantum Gravity
Class.Quant.Grav. 17 (2000) 3335-3352
10.1088/0264-9381/17/16/316
null
gr-qc hep-th
null
Following the subtraction procedure for manifolds with boundaries, we calculate by variational methods, the Schwarzschild-Anti-de Sitter and the Anti-de Sitter space energy difference. By computing the one loop approximation for TT tensors we discover the existence of an unstable mode at zero temperature, which can b...
[ { "created": "Wed, 21 Jun 2000 16:25:18 GMT", "version": "v1" } ]
2009-10-31
[ [ "Garattini", "Remo", "" ] ]
Following the subtraction procedure for manifolds with boundaries, we calculate by variational methods, the Schwarzschild-Anti-de Sitter and the Anti-de Sitter space energy difference. By computing the one loop approximation for TT tensors we discover the existence of an unstable mode at zero temperature, which can be ...
2309.00865
Lorenzo Fatibene
S.Carloni, L.Fatibene, M.Ferraris, R.G.McLenaghan, A.Orizzonte
Relativistic GPS in 3-dimensions
29 pages, 8 figures
null
null
null
gr-qc
http://creativecommons.org/licenses/by/4.0/
We extend to three dimensions the proposal of a completely relativistic positioning system (rPS). The system does not rely on approximations, in fact, it works at a few Schwarzschild radii from a black hole, and it does not rely on Newtonian physics or special relativity. Since general relativity (GR) claims to be ou...
[ { "created": "Sat, 2 Sep 2023 08:42:57 GMT", "version": "v1" } ]
2023-09-06
[ [ "Carloni", "S.", "" ], [ "Fatibene", "L.", "" ], [ "Ferraris", "M.", "" ], [ "McLenaghan", "R. G.", "" ], [ "Orizzonte", "A.", "" ] ]
We extend to three dimensions the proposal of a completely relativistic positioning system (rPS). The system does not rely on approximations, in fact, it works at a few Schwarzschild radii from a black hole, and it does not rely on Newtonian physics or special relativity. Since general relativity (GR) claims to be our ...
gr-qc/0102043
Maurice H. P. M. van Putten
Maurice H.P.M. van Putten
Gravitational radiation from long gamma-ray bursts
submitted; Presented at the 2001 Aspen Winter Conference on Gravitational Waves, Feb. 4-10, 2001, Aspen
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gr-qc astro-ph
null
Long gamma-ray bursts (GRBs) are probably powered by high-angular momentum black hole-torus systems in suspended accretion. The torus will radiate gravitational waves as non-axisymmetric instabilities develop. The luminosity in gravitational-wave emissions is expected to compare favorably with the observed isotropic ...
[ { "created": "Sun, 11 Feb 2001 19:31:00 GMT", "version": "v1" } ]
2007-05-23
[ [ "van Putten", "Maurice H. P. M.", "" ] ]
Long gamma-ray bursts (GRBs) are probably powered by high-angular momentum black hole-torus systems in suspended accretion. The torus will radiate gravitational waves as non-axisymmetric instabilities develop. The luminosity in gravitational-wave emissions is expected to compare favorably with the observed isotropic eq...