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2301.04457
Maria Caruana
Salvatore Capozziello, Maria Caruana, Jackson Levi Said, Joseph Sultana
Ghost and Laplacian Instabilities in the Teleparallel Horndeski Gravity
null
null
10.1088/1475-7516/2023/03/060
null
gr-qc astro-ph.CO hep-th
http://creativecommons.org/licenses/by/4.0/
Teleparallel geometry offers a platform on which to build up theories of gravity where torsion rather than curvature mediates gravitational interaction. The teleparallel analogue of Horndeski gravity is an approach to teleparallel geometry where scalar-tensor theories are considered in this torsional framework. Being...
[ { "created": "Wed, 11 Jan 2023 13:37:54 GMT", "version": "v1" }, { "created": "Mon, 13 Mar 2023 20:34:46 GMT", "version": "v2" } ]
2023-04-03
[ [ "Capozziello", "Salvatore", "" ], [ "Caruana", "Maria", "" ], [ "Said", "Jackson Levi", "" ], [ "Sultana", "Joseph", "" ] ]
Teleparallel geometry offers a platform on which to build up theories of gravity where torsion rather than curvature mediates gravitational interaction. The teleparallel analogue of Horndeski gravity is an approach to teleparallel geometry where scalar-tensor theories are considered in this torsional framework. Being t...
1503.08712
Mohd. Shahalam
M. Shahalam, S. D. Pathak, M. M. Verma, M. Yu. Khlopov, R. Myrzakulov
Dynamics of interacting quintessence
11 pages, 3 figures, matches with the published version
Eur. Phys. J. C (2015) 75:395
10.1140/epjc/s10052-015-3608-1
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we investigate coupled quintessence with scaling potential assuming specific forms of the coupling as $A$ namely, $\alpha \dot{\rho_m}$, $\beta \dot{\rho_{\phi}}$ and $\sigma (\dot{\rho_m}+\dot{\rho_{\phi}})$, and present phase space analysis for three different interacting models. We focus on the attr...
[ { "created": "Fri, 27 Mar 2015 06:30:23 GMT", "version": "v1" }, { "created": "Fri, 28 Aug 2015 17:11:09 GMT", "version": "v2" } ]
2015-08-31
[ [ "Shahalam", "M.", "" ], [ "Pathak", "S. D.", "" ], [ "Verma", "M. M.", "" ], [ "Khlopov", "M. Yu.", "" ], [ "Myrzakulov", "R.", "" ] ]
In this paper, we investigate coupled quintessence with scaling potential assuming specific forms of the coupling as $A$ namely, $\alpha \dot{\rho_m}$, $\beta \dot{\rho_{\phi}}$ and $\sigma (\dot{\rho_m}+\dot{\rho_{\phi}})$, and present phase space analysis for three different interacting models. We focus on the attrac...
gr-qc/0510115
Benjamin C. Harms
R. Casadio, P. H. Cox, B. Harms and O. Micu
Moving mirrors and black hole evaporation in non-commutative space-times
7 pages, 1 figure
Phys.Rev.D73:044019,2006
10.1103/PhysRevD.73.044019
null
gr-qc
null
We study the evaporation of black holes in non-commutative space-times. We do this by calculating the correction to the detector's response function for a moving mirror in terms of the noncommutativity parameter $\Theta$ and then extracting the number density as modified by this parameter. We find that allowing space...
[ { "created": "Wed, 26 Oct 2005 19:42:57 GMT", "version": "v1" } ]
2008-11-26
[ [ "Casadio", "R.", "" ], [ "Cox", "P. H.", "" ], [ "Harms", "B.", "" ], [ "Micu", "O.", "" ] ]
We study the evaporation of black holes in non-commutative space-times. We do this by calculating the correction to the detector's response function for a moving mirror in terms of the noncommutativity parameter $\Theta$ and then extracting the number density as modified by this parameter. We find that allowing space a...
gr-qc/0210013
Bei-Lok Hu
Sukanya Sinha, Alpan Raval, B. L. Hu
Black Hole Fluctuations and Backreaction in Stochastic Gravity
Latex 23 pages. To appear in a special issue of Foundations of Physics {\it Thirty Years of Black Hole Physics} edited by L. Horwitz.}
Found.Phys.33:37-64,2003
10.1023/A:1022815724856
umdpp 03-20
gr-qc
null
We present a framework for analyzing black hole backreaction from the point of view of quantum open systems using influence functional formalism. We focus on the model of a black hole described by a radially perturbed quasi-static metric and Hawking radiation by a conformally coupled massless quantum scalar field. It...
[ { "created": "Fri, 4 Oct 2002 16:30:15 GMT", "version": "v1" } ]
2014-11-17
[ [ "Sinha", "Sukanya", "" ], [ "Raval", "Alpan", "" ], [ "Hu", "B. L.", "" ] ]
We present a framework for analyzing black hole backreaction from the point of view of quantum open systems using influence functional formalism. We focus on the model of a black hole described by a radially perturbed quasi-static metric and Hawking radiation by a conformally coupled massless quantum scalar field. It i...
gr-qc/0611001
Valerii Dryuma sem
Valerii Dryuma
On solutions of a Heavenly equations and their generalizations
14 pages
null
null
null
gr-qc
null
Some solutions of the Heavenly equations and their generalizations are considered
[ { "created": "Tue, 31 Oct 2006 22:12:14 GMT", "version": "v1" } ]
2007-05-23
[ [ "Dryuma", "Valerii", "" ] ]
Some solutions of the Heavenly equations and their generalizations are considered
2102.13466
Bekir Can L\"utf\"uo\u{g}lu
N. Farahani, H. Hassanabadi, W.S. Chung, B.C. Lutfuoglu, S. Zarrinkamar
Hawking temperature of black holes using the EUP and EGUP formalisms based on the Einstein-Bohr's photon box
11 pages, 7 figures
EPL, 132 50009 (2020)
10.1209/0295-5075/132/50009
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, by studying the Einstein-Bohr's photon box for weighting a photon, we find that the effective Newton constant can be proposed by the extended uncertainty principle and extended generalized uncertainty principle. We obtain the modified Hawking temperature, mass, specific heat, and entropy by using the m...
[ { "created": "Wed, 24 Feb 2021 21:57:40 GMT", "version": "v1" } ]
2021-03-01
[ [ "Farahani", "N.", "" ], [ "Hassanabadi", "H.", "" ], [ "Chung", "W. S.", "" ], [ "Lutfuoglu", "B. C.", "" ], [ "Zarrinkamar", "S.", "" ] ]
In this paper, by studying the Einstein-Bohr's photon box for weighting a photon, we find that the effective Newton constant can be proposed by the extended uncertainty principle and extended generalized uncertainty principle. We obtain the modified Hawking temperature, mass, specific heat, and entropy by using the mod...
2002.01149
Ramil Izmailov N
R.N. Izmailov, R.Kh. Karimov, A.A. Potapov and K.K. Nandi
String effect on the relative time delay in the Kerr-Sen black hole
9 pages, 2 figures, 2 tables
Ann. Phys. 413, 168069 (2020)
10.1016/j.aop.2020.168069
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A well known solution of heterotic string theory is the spinning Kerr-Sen black hole (KSBH) characterized by a string parameter $\xi$. Kerr black hole is recovered at $\xi=0$. The purpose of this paper is to investigate the effect of $\xi$ on a new diagnostic of relative time delay (RTD) to see how the latter deviate...
[ { "created": "Tue, 4 Feb 2020 06:44:36 GMT", "version": "v1" } ]
2020-02-12
[ [ "Izmailov", "R. N.", "" ], [ "Karimov", "R. Kh.", "" ], [ "Potapov", "A. A.", "" ], [ "Nandi", "K. K.", "" ] ]
A well known solution of heterotic string theory is the spinning Kerr-Sen black hole (KSBH) characterized by a string parameter $\xi$. Kerr black hole is recovered at $\xi=0$. The purpose of this paper is to investigate the effect of $\xi$ on a new diagnostic of relative time delay (RTD) to see how the latter deviates ...
gr-qc/0206087
Pankaj S. Joshi
Pankaj S. Joshi
Cosmic Censorship: A Current Perspective
Invited talk at the Workshop "Interface of gravitational and quantum realms"; IUCAA, Pune, to appear in Mod.Phys.Letts. A; 13 pages
null
null
null
gr-qc
null
End state of gravitational collapse and the related cosmic censorship conjecture continue to be amongst the most important open problems in gravitation physics today. My purpose here is to bring out several aspects related to gravitational collapse and censorship, which may help towards a better understanding of the ...
[ { "created": "Fri, 28 Jun 2002 12:11:46 GMT", "version": "v1" } ]
2007-05-23
[ [ "Joshi", "Pankaj S.", "" ] ]
End state of gravitational collapse and the related cosmic censorship conjecture continue to be amongst the most important open problems in gravitation physics today. My purpose here is to bring out several aspects related to gravitational collapse and censorship, which may help towards a better understanding of the is...
1308.1685
Aidan Keane
Jaume Carot, Aidan J Keane, Brian O J Tupper
Conformally reducible 1+3 spacetimes
Equations (9) and (11) corrected. Table 14, metric in first row corrected
Class. Quantum Grav. 25, 055002 (2008)
10.1088/0264-9381/25/5/055002
null
gr-qc math-ph math.MP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Spacetimes which are conformally related to reducible 1+3 spacetimes are considered. We classify these spacetimes according to the conformal algebra of the underlying reducible spacetime, giving in each case canonical expressions for the metric and conformal Killing vectors, and provide physically meaningful examples...
[ { "created": "Wed, 7 Aug 2013 20:01:17 GMT", "version": "v1" } ]
2013-08-09
[ [ "Carot", "Jaume", "" ], [ "Keane", "Aidan J", "" ], [ "Tupper", "Brian O J", "" ] ]
Spacetimes which are conformally related to reducible 1+3 spacetimes are considered. We classify these spacetimes according to the conformal algebra of the underlying reducible spacetime, giving in each case canonical expressions for the metric and conformal Killing vectors, and provide physically meaningful examples.
gr-qc/0204057
Sascha Husa
Sascha Husa
Numerical relativity with the conformal field equations
34 pages, submitted to the Proceedings of the 2001 Spanish Relativity meeting, eds. L. Fernandez and L. Gonzalez, to be published by Springer, Lecture Notes in Physics series
Lect.Notes Phys. 617 (2003) 159-192
10.1007/3-540-36973-2_9
AEI-2002-031
gr-qc
null
I discuss the conformal approach to the numerical simulation of radiating isolated systems in general relativity. The method is based on conformal compactification and a reformulation of the Einstein equations in terms of rescaled variables, the so-called ``conformal field equations'' developed by Friedrich. These eq...
[ { "created": "Wed, 17 Apr 2002 16:11:13 GMT", "version": "v1" } ]
2022-09-21
[ [ "Husa", "Sascha", "" ] ]
I discuss the conformal approach to the numerical simulation of radiating isolated systems in general relativity. The method is based on conformal compactification and a reformulation of the Einstein equations in terms of rescaled variables, the so-called ``conformal field equations'' developed by Friedrich. These equa...
1801.09098
David Lucchesi
Massimo Visco, David M. Lucchesi
The LArase Satellites Spin mOdel Solutions (LASSOS): a comprehensive model for the spin evolution of the LAGEOS and LARES satellites
null
Phys. Rev. D 98, 044034 (2018)
10.1103/PhysRevD.98.044034
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The two LAGEOS and LARES are laser-ranged satellites tracked with the best accuracy ever achieved. Using their range measurements many geophysical parameters were calculated and some General Relativity effects were directly observed. To obtain precise and refined measurements of the effects due to the predictions of ...
[ { "created": "Sat, 27 Jan 2018 14:50:51 GMT", "version": "v1" } ]
2018-08-29
[ [ "Visco", "Massimo", "" ], [ "Lucchesi", "David M.", "" ] ]
The two LAGEOS and LARES are laser-ranged satellites tracked with the best accuracy ever achieved. Using their range measurements many geophysical parameters were calculated and some General Relativity effects were directly observed. To obtain precise and refined measurements of the effects due to the predictions of Ge...
2407.08207
Dipankar Laya
Dipanakr Laya, Roshni Bhaumik, Sourav Dutta, Subenoy Chakraborty
Classical and Quantum Cosmology in Einstein-aether Scalar-tensor gravity: Noether Symmetry Analysis
15 pages, 4 figures
International Journal of Modern Physics A Vol. 38, Nos. 12 & 13 (2023) 2350064 (14 pages)
10.1142/S0217751X23500641
null
gr-qc
http://creativecommons.org/licenses/by/4.0/
The present work deals with Einstein-aether Scalar tensor gravity in the background of homogeneous and isotropic flat FLRW space-time model. The Noether symmetry vector identifies a transformation in the augmented space so that the field equations become solvable. The cosmological solutions are analyzed from the obse...
[ { "created": "Thu, 11 Jul 2024 06:20:47 GMT", "version": "v1" } ]
2024-07-12
[ [ "Laya", "Dipanakr", "" ], [ "Bhaumik", "Roshni", "" ], [ "Dutta", "Sourav", "" ], [ "Chakraborty", "Subenoy", "" ] ]
The present work deals with Einstein-aether Scalar tensor gravity in the background of homogeneous and isotropic flat FLRW space-time model. The Noether symmetry vector identifies a transformation in the augmented space so that the field equations become solvable. The cosmological solutions are analyzed from the observ...
gr-qc/0409027
Oscar Alejandro Reula
Oscar Reula, and Olivier Sarbach
A model problem for the initial-boundary value formulation of Einstein's field equations
25 pages
J.Hyperbol.Diff.Equat.2:397,2005
10.1142/S0219891605000488
null
gr-qc
null
In many numerical implementations of the Cauchy formulation of Einstein's field equations one encounters artificial boundaries which raises the issue of specifying boundary conditions. Such conditions have to be chosen carefully. In particular, they should be compatible with the constraints, yield a well posed initia...
[ { "created": "Mon, 6 Sep 2004 21:33:53 GMT", "version": "v1" } ]
2010-09-06
[ [ "Reula", "Oscar", "" ], [ "Sarbach", "Olivier", "" ] ]
In many numerical implementations of the Cauchy formulation of Einstein's field equations one encounters artificial boundaries which raises the issue of specifying boundary conditions. Such conditions have to be chosen carefully. In particular, they should be compatible with the constraints, yield a well posed initial-...
1904.13060
Morgan Le Delliou
Antonino Del Popolo, Maksym Deliyergiyev, Morgan Le Delliou, Laura Tolos, and Fiorella Burgio
On the change of old neutron star masses with galactocentric distance
30pp 2figs
Physics of the Dark Universe, 28 (2020) 100484
10.1016/j.dark.2020.100484
null
gr-qc astro-ph.HE hep-ph nucl-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show that the pulsar mass depends on the environment, and that it decreases going towards the center of the Milky Way. This is due to two combined effects, the capture and accumulation of self-interacting, non-annihilating dark matter by pulsars, and the increase of the dark matter density going towards the galact...
[ { "created": "Tue, 30 Apr 2019 05:57:40 GMT", "version": "v1" }, { "created": "Thu, 6 Feb 2020 15:13:29 GMT", "version": "v2" } ]
2020-02-10
[ [ "Del Popolo", "Antonino", "" ], [ "Deliyergiyev", "Maksym", "" ], [ "Delliou", "Morgan Le", "" ], [ "Tolos", "Laura", "" ], [ "Burgio", "Fiorella", "" ] ]
We show that the pulsar mass depends on the environment, and that it decreases going towards the center of the Milky Way. This is due to two combined effects, the capture and accumulation of self-interacting, non-annihilating dark matter by pulsars, and the increase of the dark matter density going towards the galactic...
gr-qc/9301018
John D. Brown
J. David Brown and James W. York
Jacobi's Action and the Density of States
10 pages, plain tex. (This replaces the previous version which consisted of less than half of the manuscript.)
null
null
null
gr-qc hep-th
null
The authors have introduced recently a ``microcanonical functional integral" which yields directly the density of states as a function of energy. The phase of the functional integral is Jacobi's action, the extrema of which are classical solutions at a given energy. This approach is general but is especially well sui...
[ { "created": "Mon, 18 Jan 1993 19:48:56 GMT", "version": "v1" }, { "created": "Tue, 19 Jan 1993 20:10:42 GMT", "version": "v2" } ]
2008-02-03
[ [ "Brown", "J. David", "" ], [ "York", "James W.", "" ] ]
The authors have introduced recently a ``microcanonical functional integral" which yields directly the density of states as a function of energy. The phase of the functional integral is Jacobi's action, the extrema of which are classical solutions at a given energy. This approach is general but is especially well suite...
1904.09670
Nishanth Abu Gudapati
Nishanth Gudapati
Axially Symmetric Perturbations of Kerr Black Holes I: A gauge-invariant construction of ADM Energy
null
null
null
null
gr-qc math.DG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Based on the Hamiltonian dimensional reduction of $3+1$ axially symmetric, Ricci-flat Lorentzian spacetimes to a $2+1$ Einstein-wave map system with the (negatively curved) hyperbolic 2-plane target, we construct a positive-definite, (spacetime) gauge-invariant energy functional for linear axially symmetric perturbat...
[ { "created": "Sun, 21 Apr 2019 22:33:51 GMT", "version": "v1" } ]
2019-04-23
[ [ "Gudapati", "Nishanth", "" ] ]
Based on the Hamiltonian dimensional reduction of $3+1$ axially symmetric, Ricci-flat Lorentzian spacetimes to a $2+1$ Einstein-wave map system with the (negatively curved) hyperbolic 2-plane target, we construct a positive-definite, (spacetime) gauge-invariant energy functional for linear axially symmetric perturbatio...
2003.07226
Subenoy Chakraborty
Akash Bose, Subenoy Chakraborty
Homogeneous and Isotropic space-time, Modified torsion field and Complete cosmic scenario
8 pages,4 figures
Eur. Phys. J. C (2020) 80:205
10.1140/epjc/s10052-020-7771-7
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The paper deals with cosmological solutions describing different phases of the Universe for the homogeneous and isotropic FLRW model of the Universe with torsion. Normally, torsion field is not suitable for maximally symmetric space time model. However, one may use a specific profile of vectorial torsion field, deriv...
[ { "created": "Fri, 13 Mar 2020 10:41:36 GMT", "version": "v1" }, { "created": "Thu, 29 Oct 2020 16:00:05 GMT", "version": "v2" } ]
2020-10-30
[ [ "Bose", "Akash", "" ], [ "Chakraborty", "Subenoy", "" ] ]
The paper deals with cosmological solutions describing different phases of the Universe for the homogeneous and isotropic FLRW model of the Universe with torsion. Normally, torsion field is not suitable for maximally symmetric space time model. However, one may use a specific profile of vectorial torsion field, derived...
0908.2043
Sophie Pireaux Dr
Bertrand Chauvineau (1), Sophie Pireaux (1,2), Tania Regimbau (1), ((1) Observatoire de la Cote d'Azur, France; (2) Observatoire Royal de Belgique, Belgium)
Shapiro delay of asteroids on LISA
9 pages, 1 figure, published in Classical and Quantum Gravity
Class.Quant.Grav.24:3005-3011,2007
10.1088/0264-9381/24/11/013
null
gr-qc physics.space-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we examine the Shapiro delay caused by the close approach of an asteroid to the LISA constellation. We find that the probability that such an event occurs at a detectable level during the time interval of the mission is smaller than 1 %.
[ { "created": "Fri, 14 Aug 2009 11:37:04 GMT", "version": "v1" } ]
2009-08-19
[ [ "Chauvineau", "Bertrand", "" ], [ "Pireaux", "Sophie", "" ], [ "Regimbau", "Tania", "" ] ]
In this paper, we examine the Shapiro delay caused by the close approach of an asteroid to the LISA constellation. We find that the probability that such an event occurs at a detectable level during the time interval of the mission is smaller than 1 %.
gr-qc/0304006
Vladimir M. Khatsymovsky
V.M.Khatsymovsky
Regge calculus from discontinuous metrics
8 pages, LaTeX
Phys.Lett. B567 (2003) 288-293
10.1016/j.physletb.2003.06.020
null
gr-qc
null
Regge calculus is considered as a particular case of the more general system where the linklengths of any two neighbouring 4-tetrahedra do not necessarily coincide on their common face. This system is treated as that one described by metric discontinuous on the faces. In the superspace of all discontinuous metrics th...
[ { "created": "Tue, 1 Apr 2003 14:09:51 GMT", "version": "v1" } ]
2009-11-10
[ [ "Khatsymovsky", "V. M.", "" ] ]
Regge calculus is considered as a particular case of the more general system where the linklengths of any two neighbouring 4-tetrahedra do not necessarily coincide on their common face. This system is treated as that one described by metric discontinuous on the faces. In the superspace of all discontinuous metrics the ...
1105.3060
Mohammad Reza Tanhayi
M.V. Takook, H. Pejhan and M.Reza Tanhayi
Conformal linear gravity in de Sitter space II
16 pages, no figure, published version
Eur. Phys. J. C (2012) 72:2052
10.1140/epjc/s10052-012-2052-8
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
From the group theoretical point of view, it is proved that the theory of linear conformal gravity should be written in terms of a tensor field of rank-3 and mixed symmetry [Binegar, et al, Phys. Rev. D 27, (1983) 2249]. We obtained such a field equation in de Sitter space [Takook, et al, J. Math. Phys. 51, (2010) 03...
[ { "created": "Mon, 16 May 2011 10:54:37 GMT", "version": "v1" }, { "created": "Sun, 4 Sep 2011 18:05:10 GMT", "version": "v2" }, { "created": "Thu, 26 Apr 2012 14:22:32 GMT", "version": "v3" }, { "created": "Sat, 7 Jul 2012 08:27:45 GMT", "version": "v4" } ]
2012-07-10
[ [ "Takook", "M. V.", "" ], [ "Pejhan", "H.", "" ], [ "Tanhayi", "M. Reza", "" ] ]
From the group theoretical point of view, it is proved that the theory of linear conformal gravity should be written in terms of a tensor field of rank-3 and mixed symmetry [Binegar, et al, Phys. Rev. D 27, (1983) 2249]. We obtained such a field equation in de Sitter space [Takook, et al, J. Math. Phys. 51, (2010) 0325...
2312.09550
Chan Park
Danho Ahn, Yeong-Bok Bae, Sang Hui Im, and Chan Park
Electromagnetic field in a cavity induced by gravitational waves
null
null
null
CTPU-PTC-23-53
gr-qc astro-ph.IM hep-ex hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The detection method of gravitational waves (GW) using electromagnetic (EM) cavities has garnered significant attention in recent years. This paper thoroughly examines the analysis for the perturbation of the EM field and raises some issues in the existing literature. Our work demonstrates that the rigid condition im...
[ { "created": "Fri, 15 Dec 2023 06:03:28 GMT", "version": "v1" } ]
2023-12-20
[ [ "Ahn", "Danho", "" ], [ "Bae", "Yeong-Bok", "" ], [ "Im", "Sang Hui", "" ], [ "Park", "Chan", "" ] ]
The detection method of gravitational waves (GW) using electromagnetic (EM) cavities has garnered significant attention in recent years. This paper thoroughly examines the analysis for the perturbation of the EM field and raises some issues in the existing literature. Our work demonstrates that the rigid condition impo...
1310.3069
Saira Waheed
M. Sharif and Saira Waheed
Dynamics of Potentials in Bianchi Type Scalar-Tensor Cosmology
20 pages, 4 figures. Phys. Lett. B (2013)
null
10.1016/j.physletb.2013.08.044
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The present study investigates the nature of the field potential via new technique known as reconstruction method for the scalar field potentials. The key point of this technique is the assumption that Hubble parameter is dependent on the scalar field. We consider Bianchi type I universe in the gravitational framewor...
[ { "created": "Fri, 11 Oct 2013 09:53:54 GMT", "version": "v1" } ]
2013-10-14
[ [ "Sharif", "M.", "" ], [ "Waheed", "Saira", "" ] ]
The present study investigates the nature of the field potential via new technique known as reconstruction method for the scalar field potentials. The key point of this technique is the assumption that Hubble parameter is dependent on the scalar field. We consider Bianchi type I universe in the gravitational framework ...
1203.4446
Massimiliano Rinaldi
Jean-Philippe Bruneton and Massimiliano Rinaldi and Antonin Kanfon and Aur\'elien Hees and Sandrine Schl\"ogel and Andr\'e F\"uzfa
Fab Four: When John and George play gravitation and cosmology
Minor changes, references added. Version accepted for publication in Advances in Astronomy
Advances in Astronomy, Volume 2012 (2012), 430694
10.1155/2012/430694
null
gr-qc astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Scalar-tensor theories of gravitation have recently regained a great interest after the discovery of the Chameleon mechanism and of the Galileon models. The former allows, in principle, to reconcile the presence of cosmological scalar fields with the constraints from experiments at the Solar System scale. The latter ...
[ { "created": "Tue, 20 Mar 2012 14:11:57 GMT", "version": "v1" }, { "created": "Mon, 5 Nov 2012 07:23:22 GMT", "version": "v2" }, { "created": "Tue, 6 Nov 2012 14:24:17 GMT", "version": "v3" } ]
2013-01-08
[ [ "Bruneton", "Jean-Philippe", "" ], [ "Rinaldi", "Massimiliano", "" ], [ "Kanfon", "Antonin", "" ], [ "Hees", "Aurélien", "" ], [ "Schlögel", "Sandrine", "" ], [ "Füzfa", "André", "" ] ]
Scalar-tensor theories of gravitation have recently regained a great interest after the discovery of the Chameleon mechanism and of the Galileon models. The former allows, in principle, to reconcile the presence of cosmological scalar fields with the constraints from experiments at the Solar System scale. The latter op...
gr-qc/0302025
Luciano Rezzolla
Luciano Rezzolla
Gravitational Waves from Perturbed Black Holes and Relativistic Stars
Lectures given at the Summer School on Astroparticle Physics and Cosmology, ICTP, July 2002 (47 pages, 9 figs)
ICTP Lecture Series, Vol. 3, (2003) ISBN 92-95003-05-5
null
null
gr-qc astro-ph
null
These lectures aim at providing an introduction to the properties of gravitational waves and in particular to those gravitational waves that are expected as a consequence of perturbations of black holes and neutron stars. Imprinted in the gravitational radiation emitted by these objects is, in fact, a wealth of physi...
[ { "created": "Fri, 7 Feb 2003 18:26:17 GMT", "version": "v1" } ]
2009-04-16
[ [ "Rezzolla", "Luciano", "" ] ]
These lectures aim at providing an introduction to the properties of gravitational waves and in particular to those gravitational waves that are expected as a consequence of perturbations of black holes and neutron stars. Imprinted in the gravitational radiation emitted by these objects is, in fact, a wealth of physica...
1512.03268
Giulia Gubitosi
Giulia Gubitosi and Joao Magueijo
Reappraisal of a model for deformed special relativity
null
null
10.1088/0264-9381/33/11/115021
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We revisit one of the earliest proposals for deformed dispersion relations in the light of recent results on dynamical dimensional reduction and production of cosmological fluctuations. Depending on the specification of the measure of integration and addition rule in momentum space the model may be completed so as to...
[ { "created": "Thu, 10 Dec 2015 14:35:55 GMT", "version": "v1" } ]
2016-05-25
[ [ "Gubitosi", "Giulia", "" ], [ "Magueijo", "Joao", "" ] ]
We revisit one of the earliest proposals for deformed dispersion relations in the light of recent results on dynamical dimensional reduction and production of cosmological fluctuations. Depending on the specification of the measure of integration and addition rule in momentum space the model may be completed so as to m...
2204.03901
Daniela Pugliese Dr
D. Pugliese and Z. Stuchl{\i}k
Dragged surfaces. On the accretion tori in the ergoregion
43 pages, 40 figure multipanels, 2 tables
PASJ-Volume 73, Issue 6, pp.1497-1539 (December 2021)
10.1093/pasj/psab093
null
gr-qc astro-ph.HE
http://creativecommons.org/licenses/by-nc-nd/4.0/
We discuss the conditions for the existence of extended matter configurations orbiting in the ergoregion or close to the outer ergosurface of the Kerr black hole ("dragged" configurations). The corotating tori under consideration are perfect fluid configurations with barotropic equation of state, orbiting on the equa...
[ { "created": "Fri, 8 Apr 2022 08:03:06 GMT", "version": "v1" } ]
2022-04-11
[ [ "Pugliese", "D.", "" ], [ "Stuchlık", "Z.", "" ] ]
We discuss the conditions for the existence of extended matter configurations orbiting in the ergoregion or close to the outer ergosurface of the Kerr black hole ("dragged" configurations). The corotating tori under consideration are perfect fluid configurations with barotropic equation of state, orbiting on the equato...
gr-qc/9709062
My Account
Hyeong-Chan Kim (Sung Kyun Kwan Univ.) and Min-Ho Lee (Kumoh Univ.) Jeong-Young Ji (Seoul National Univ.)
The origin of the area law of the entropy of a quantum field in a black hole
4 pages, revtex
null
null
SKKU-97/H2
gr-qc
null
It is shown that that the area law for the entropy of a quantum field in the Schwarzschild black hole is due to the quantum statistics. The entropies for one particle, a Boltzmann gas, a quantum mechanical gas obeying Bose-Einstein or Fermi-Dirac statistics, and a quantum field in the Schwarzschild black hole are cal...
[ { "created": "Wed, 24 Sep 1997 16:00:52 GMT", "version": "v1" } ]
2007-05-23
[ [ "Kim", "Hyeong-Chan", "", "Sung Kyun Kwan Univ." ], [ "Lee", "Min-Ho", "", "Kumoh Univ." ], [ "Ji", "Jeong-Young", "", "Seoul National Univ." ] ]
It is shown that that the area law for the entropy of a quantum field in the Schwarzschild black hole is due to the quantum statistics. The entropies for one particle, a Boltzmann gas, a quantum mechanical gas obeying Bose-Einstein or Fermi-Dirac statistics, and a quantum field in the Schwarzschild black hole are calcu...
gr-qc/9606002
Ruth A. W. Gregory
Ruth Gregory
Nonsingular global strings
21 pages plain TEX, 4 figs. Published version (minor error corrected)
Phys.Rev. D54 (1996) 4955-4962
10.1103/PhysRevD.54.4955
DTP/96/25
gr-qc astro-ph hep-ph hep-th
null
We examine the possibility that time dependence might remove the singular nature of global string spacetimes. We first show that this time dependence takes a specific form -- a de-Sitter like expansion along the length of the string and give an argument for the existence of such a solution, estimating the rate of exp...
[ { "created": "Tue, 4 Jun 1996 10:01:55 GMT", "version": "v1" }, { "created": "Fri, 17 Oct 1997 09:44:24 GMT", "version": "v2" } ]
2009-10-28
[ [ "Gregory", "Ruth", "" ] ]
We examine the possibility that time dependence might remove the singular nature of global string spacetimes. We first show that this time dependence takes a specific form -- a de-Sitter like expansion along the length of the string and give an argument for the existence of such a solution, estimating the rate of expan...
0711.2019
Roberto Casadio
Corrado Appignani and Roberto Casadio
Hints of (trans-Planckian) asymptotic freedom in semiclassical cosmology
11 pages, 2 figures; replaced to match content of published version
JCAP0806:014,2008
10.1088/1475-7516/2008/06/014
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We employ the semiclassical approximation to the Wheeler-DeWitt equation in the spatially flat de Sitter Universe to investigate the dynamics of a minimally coupled scalar field near the Planck scale. We find that, contrary to naive intuition, the effects of quantum gravitational fluctuations become negligible and th...
[ { "created": "Tue, 13 Nov 2007 16:09:29 GMT", "version": "v1" }, { "created": "Tue, 15 Apr 2008 18:58:56 GMT", "version": "v2" }, { "created": "Thu, 24 Jul 2008 09:15:28 GMT", "version": "v3" } ]
2008-11-07
[ [ "Appignani", "Corrado", "" ], [ "Casadio", "Roberto", "" ] ]
We employ the semiclassical approximation to the Wheeler-DeWitt equation in the spatially flat de Sitter Universe to investigate the dynamics of a minimally coupled scalar field near the Planck scale. We find that, contrary to naive intuition, the effects of quantum gravitational fluctuations become negligible and the ...
2310.19838
Liubov Panasenko
A. D. Dolgov, L. A. Panasenko, V. A. Bochko
Graviton to photon conversion in curved space-time and external magnetic field
38 pages, 2 figures
Universe (ISSN 2218-1997)
10.3390/universe10010007
null
gr-qc astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The suppression of relic gravitational waves due to their conversion into electromagnetic radiation in a cosmological magnetic field is studied. The coupled system of equations describing gravitational and electromagnetic wave propagation in an arbitrary curved space-time and in external magnetic field is derived. Th...
[ { "created": "Mon, 30 Oct 2023 03:13:37 GMT", "version": "v1" }, { "created": "Tue, 26 Dec 2023 03:03:59 GMT", "version": "v2" } ]
2023-12-27
[ [ "Dolgov", "A. D.", "" ], [ "Panasenko", "L. A.", "" ], [ "Bochko", "V. A.", "" ] ]
The suppression of relic gravitational waves due to their conversion into electromagnetic radiation in a cosmological magnetic field is studied. The coupled system of equations describing gravitational and electromagnetic wave propagation in an arbitrary curved space-time and in external magnetic field is derived. The ...
1905.00408
Tiziano Abdelsalhin
Tiziano Abdelsalhin
Tidal deformations of compact objects and gravitational wave emission
PhD thesis. Related publications: arXiv:1712.01303 (Abdelsalhin et al., PRD, 2018), arXiv:1805.01487 (Abdelsalhin et al., PRD, 2018) and arXiv:1807.08016 (Jimenez-Forteza et al., PRD, 2018)
null
null
null
gr-qc astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Observations of gravitational wave (GW) signals produced by coalescing binary neutron stars (NS), like the GW event GW170817, can be exploited to constrain the equation of state (EoS) of matter in the stars' inner core. The information on the internal structure and composition of the stars is encoded in their tidal L...
[ { "created": "Wed, 1 May 2019 17:49:19 GMT", "version": "v1" } ]
2019-05-02
[ [ "Abdelsalhin", "Tiziano", "" ] ]
Observations of gravitational wave (GW) signals produced by coalescing binary neutron stars (NS), like the GW event GW170817, can be exploited to constrain the equation of state (EoS) of matter in the stars' inner core. The information on the internal structure and composition of the stars is encoded in their tidal Lov...
2304.13058
Alexander Florian Jercher
Alexander Jercher, Sebastian Steinhaus, Johannes Th\"urigen
Curvature effects in the spectral dimension of spin foams
52 pages, 24 figures
Phys. Rev. D 108, 066011, 14 September 2023
10.1103/PhysRevD.108.066011
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It has been shown in [1] that a class of restricted spin foam models can feature a reduced spectral dimension of space-time. However, it is still an open question how curvature affects the flow of the spectral dimension. To answer this question, we consider another class of restricted spin foam models, so called spin...
[ { "created": "Tue, 25 Apr 2023 18:00:06 GMT", "version": "v1" }, { "created": "Fri, 15 Sep 2023 07:06:15 GMT", "version": "v2" } ]
2023-09-18
[ [ "Jercher", "Alexander", "" ], [ "Steinhaus", "Sebastian", "" ], [ "Thürigen", "Johannes", "" ] ]
It has been shown in [1] that a class of restricted spin foam models can feature a reduced spectral dimension of space-time. However, it is still an open question how curvature affects the flow of the spectral dimension. To answer this question, we consider another class of restricted spin foam models, so called spin f...
1006.4195
Gavin Polhemus
Gavin Polhemus and Andrew J S Hamilton
Large entropy production inside black holes: a simple model
10 pages
JHEP 1008:093,2010
10.1007/JHEP08(2010)093
null
gr-qc astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Particles dropped into a rotating black hole can collide near the inner horizon with enormous energies. The entropy produced by these collisions can be several times larger than the increase in the horizon entropy due to the addition of the particles. In this paper entropy is produced by releasing large numbers of ne...
[ { "created": "Tue, 22 Jun 2010 00:39:04 GMT", "version": "v1" } ]
2012-01-16
[ [ "Polhemus", "Gavin", "" ], [ "Hamilton", "Andrew J S", "" ] ]
Particles dropped into a rotating black hole can collide near the inner horizon with enormous energies. The entropy produced by these collisions can be several times larger than the increase in the horizon entropy due to the addition of the particles. In this paper entropy is produced by releasing large numbers of neut...
2310.19631
Vitalii Vertogradov
Timur Pryadilin, Daniil Zhitov, Vitalii Vertogradov
On particle collisions in the vicinity of the charged black holes
10 pages, accepted to Gravitation and Cosmology
null
null
null
gr-qc
http://creativecommons.org/licenses/by/4.0/
The process of particle collision in the vicinity of black holes is known to generate unbounded energies in the center-of-mass frame (the Banados-Silk-West (BSW) effect) under specific conditions. We consider this process in the charged black hole metrics, namely, the Reissner-Nordstrom (RN) and Majumdar-Papapetrou (...
[ { "created": "Mon, 30 Oct 2023 15:24:01 GMT", "version": "v1" } ]
2023-10-31
[ [ "Pryadilin", "Timur", "" ], [ "Zhitov", "Daniil", "" ], [ "Vertogradov", "Vitalii", "" ] ]
The process of particle collision in the vicinity of black holes is known to generate unbounded energies in the center-of-mass frame (the Banados-Silk-West (BSW) effect) under specific conditions. We consider this process in the charged black hole metrics, namely, the Reissner-Nordstrom (RN) and Majumdar-Papapetrou (MP...
2211.12327
Bahtiyar \"Ozg\"ur Sar{\i}o\u{g}lu
Ulf Lindstr\"om and \"Ozg\"ur Sar{\i}o\u{g}lu
A comment on Metric vs Metric-Affine Gravity
Three pages, no figures, accepted for publication in Physics Letters B
Physics Letters B 836 (2023) 137619
10.1016/j.physletb.2022.137619
UUITP-52/22
gr-qc hep-th
http://creativecommons.org/licenses/by/4.0/
We consider the sum of the Einstein-Hilbert action and a Pontryagin density (PD) in arbitrary even dimension $D$. All curvatures are functions of independent affine (torsionless) connections only. In arbitrary dimension, not only in $D=4n$, these first order PD terms are shown to be covariant divergences of "Chern-Si...
[ { "created": "Mon, 21 Nov 2022 13:03:33 GMT", "version": "v1" }, { "created": "Wed, 7 Dec 2022 11:16:04 GMT", "version": "v2" } ]
2022-12-12
[ [ "Lindström", "Ulf", "" ], [ "Sarıoğlu", "Özgür", "" ] ]
We consider the sum of the Einstein-Hilbert action and a Pontryagin density (PD) in arbitrary even dimension $D$. All curvatures are functions of independent affine (torsionless) connections only. In arbitrary dimension, not only in $D=4n$, these first order PD terms are shown to be covariant divergences of "Chern-Simo...
1804.05176
Yen Chin Ong
Yen Chin Ong
Generalized Uncertainty Principle, Black Holes, and White Dwarfs: A Tale of Two Infinities
9 pages, 6 figures; version accepted by JCAP
JCAP 09 (2018) 015
10.1088/1475-7516/2018/09/015
null
gr-qc hep-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It is often argued that quantum gravitational correction to the Heisenberg's uncertainty principle leads to, among other things, a black hole remnant with finite temperature. However, such a generalized uncertainty principle also seemingly removes the Chandrasekhar limit, i.e., it permits white dwarfs to be arbitrari...
[ { "created": "Sat, 14 Apr 2018 06:42:19 GMT", "version": "v1" }, { "created": "Mon, 3 Sep 2018 13:02:08 GMT", "version": "v2" } ]
2018-09-18
[ [ "Ong", "Yen Chin", "" ] ]
It is often argued that quantum gravitational correction to the Heisenberg's uncertainty principle leads to, among other things, a black hole remnant with finite temperature. However, such a generalized uncertainty principle also seemingly removes the Chandrasekhar limit, i.e., it permits white dwarfs to be arbitrarily...
gr-qc/9510026
Masoud Mohazzab
M. Mohazzab, M. M. Sheikh Jabbari and H. Salehi
Expansion of Bubbles in Inflationary Universe
8 pages, latex, no figures
null
null
IPM-95-90
gr-qc astro-ph hep-th
null
We show that particle production during the expansion of bubbles of true vacuum in the sea of false vacuum is possible and calculate the resulting rate. As a result the nucleated bubbles cannot expand due to the transfer of false vacuum energy to the created particles inside the bubbles. Therefore all the inflationar...
[ { "created": "Sat, 14 Oct 1995 06:20:15 GMT", "version": "v1" } ]
2007-05-23
[ [ "Mohazzab", "M.", "" ], [ "Jabbari", "M. M. Sheikh", "" ], [ "Salehi", "H.", "" ] ]
We show that particle production during the expansion of bubbles of true vacuum in the sea of false vacuum is possible and calculate the resulting rate. As a result the nucleated bubbles cannot expand due to the transfer of false vacuum energy to the created particles inside the bubbles. Therefore all the inflationary ...
1506.08613
Antonia Zipfel
Antonia Zipfel and Thomas Thiemann
Stable coherent states
null
Phys. Rev. D 93, 084030 (2016)
10.1103/PhysRevD.93.084030
null
gr-qc math-ph math.MP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We analyze the stability under time evolution of complexifier coherent states (CCS) in one-dimensional mechanical systems. A system of coherent states is called stable if it evolves into another coherent state. It turns out that a system can only poses stable CCS if the classical evolution of the variable for a given...
[ { "created": "Mon, 29 Jun 2015 13:28:15 GMT", "version": "v1" } ]
2016-04-20
[ [ "Zipfel", "Antonia", "" ], [ "Thiemann", "Thomas", "" ] ]
We analyze the stability under time evolution of complexifier coherent states (CCS) in one-dimensional mechanical systems. A system of coherent states is called stable if it evolves into another coherent state. It turns out that a system can only poses stable CCS if the classical evolution of the variable for a given c...
1402.2922
Santiago Esteban Perez Bergliaffa
Nora Bret\'on and Santiago Esteban Perez Bergliaffa
On the stability of black holes with nonlinear electromagnetic fields
14 pages, 16 figures
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The stability of three static and spherically symmetric black hole solutions with nonlinear electromagnetism as a source is investigated in three different ways. We show that the specific heat of all the solutions displays an infinite discontinuity with a change of sign, but the turning point method indicates that th...
[ { "created": "Wed, 12 Feb 2014 18:30:35 GMT", "version": "v1" } ]
2014-02-13
[ [ "Bretón", "Nora", "" ], [ "Bergliaffa", "Santiago Esteban Perez", "" ] ]
The stability of three static and spherically symmetric black hole solutions with nonlinear electromagnetism as a source is investigated in three different ways. We show that the specific heat of all the solutions displays an infinite discontinuity with a change of sign, but the turning point method indicates that the ...
2211.07835
Matt Visser
Matt Visser (Victoria University of Wellington)
Efficient computation of null affine parameters
V1: 22 pages; V2: Now 35 pages. Note change in title. Significant additions in terms of discussion, examples, and references. Closely parallels the published version
Universe 9 (2023) 521
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Finding affine parameters for null geodesics is often of considerable physical importance, especially when studying the paths swept out by null geodesics or when dealing with conservation laws and/or averaged energy conditions. But explicitly finding null affine parameters is also often quite tedious and can sometime...
[ { "created": "Tue, 15 Nov 2022 01:27:09 GMT", "version": "v1" }, { "created": "Wed, 20 Dec 2023 02:15:22 GMT", "version": "v2" } ]
2023-12-21
[ [ "Visser", "Matt", "", "Victoria University of Wellington" ] ]
Finding affine parameters for null geodesics is often of considerable physical importance, especially when studying the paths swept out by null geodesics or when dealing with conservation laws and/or averaged energy conditions. But explicitly finding null affine parameters is also often quite tedious and can sometimes ...
gr-qc/0412057
Lorenzo Iorio
Lorenzo Iorio
A critical analysis of a recent test of the Lense-Thirring effect with the LAGEOS satellites
LaTeX2e, 24 pages, 8 tables, 2 figures. This submission replaces the previous one, which was clearly wrong. I apologize for the confusion generated. This version is the one published in J. of Geodesy
J.Geod. 80 (2006) 128-136
10.1007/s00190-006-0058-4
null
gr-qc astro-ph physics.space-ph
null
We discuss the impact of the present-day uncertainties in the recently released CHAMP and/or GRACE Earth gravity models on the measurement of the Lense-Thirring effect with the nodes of the LAGEOS satellites. Also the role of the secular variations Jdots of the even zonal harmonics is quantitatively assessed via nume...
[ { "created": "Sun, 12 Dec 2004 20:09:21 GMT", "version": "v1" }, { "created": "Mon, 20 Dec 2004 23:57:56 GMT", "version": "v2" }, { "created": "Tue, 22 Feb 2005 22:15:06 GMT", "version": "v3" }, { "created": "Tue, 5 Jul 2005 13:17:11 GMT", "version": "v4" }, { "cr...
2007-05-23
[ [ "Iorio", "Lorenzo", "" ] ]
We discuss the impact of the present-day uncertainties in the recently released CHAMP and/or GRACE Earth gravity models on the measurement of the Lense-Thirring effect with the nodes of the LAGEOS satellites. Also the role of the secular variations Jdots of the even zonal harmonics is quantitatively assessed via numeri...
gr-qc/0306064
Chris Isham
C.J. Isham
A New Approach to Quantising Space-Time: III. State Vectors as Functions on Arrows
Latex2e
Adv.Theor.Math.Phys. 8 (2004) 797-811
null
null
gr-qc math-ph math.MP quant-ph
null
In two recent papers by the author, a new approach was suggested for quantising space-time, or space. This involved developing a procedure for quantising a system whose configuration space--or history-theory analogue--is the set of objects, $\Ob\Q$, in a (small) category $\Q$. The quantum states in this approach are ...
[ { "created": "Mon, 16 Jun 2003 11:15:08 GMT", "version": "v1" } ]
2007-05-23
[ [ "Isham", "C. J.", "" ] ]
In two recent papers by the author, a new approach was suggested for quantising space-time, or space. This involved developing a procedure for quantising a system whose configuration space--or history-theory analogue--is the set of objects, $\Ob\Q$, in a (small) category $\Q$. The quantum states in this approach are cr...
1708.02429
Giovanni Amelino-Camelia
Giovanni Amelino-Camelia, Leonardo Barcaroli, Stefano Bianco, Laura Pensato
Planck-scale dual-curvature lensing and spacetime noncommutativity
null
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It was recently realized that Planck-scale momentum-space curvature, which is expected in some approaches to the quantum-gravity problem, can produce dual-curvature lensing, a feature which mainly affects the direction of observation of particles emitted by very distant sources. Several gray areas remain in our under...
[ { "created": "Tue, 8 Aug 2017 09:40:55 GMT", "version": "v1" } ]
2017-08-09
[ [ "Amelino-Camelia", "Giovanni", "" ], [ "Barcaroli", "Leonardo", "" ], [ "Bianco", "Stefano", "" ], [ "Pensato", "Laura", "" ] ]
It was recently realized that Planck-scale momentum-space curvature, which is expected in some approaches to the quantum-gravity problem, can produce dual-curvature lensing, a feature which mainly affects the direction of observation of particles emitted by very distant sources. Several gray areas remain in our underst...
gr-qc/0207093
J. Frauendiener
J. Frauendiener
Some aspects of the numerical treatment of the conformal field equations
Contribution to the Proceedings of the Workshop "The conformal structure of space-times: geometry, analysis, numerics", Tuebingen April 2001. To appear in Lecture Notes in Physics, Springer Verlag, edited by J. Frauendiener and H. Friedrich
Lect.Notes Phys. 604 (2002) 261-282
null
null
gr-qc
null
Some issues in the numerical treatment of the conformal field equations are discussed. In particular, the problem of obtaining smooth initial data for the hyperboloidal initial value problem is described and solution methods are presented.
[ { "created": "Wed, 24 Jul 2002 14:01:09 GMT", "version": "v1" } ]
2007-05-23
[ [ "Frauendiener", "J.", "" ] ]
Some issues in the numerical treatment of the conformal field equations are discussed. In particular, the problem of obtaining smooth initial data for the hyperboloidal initial value problem is described and solution methods are presented.
1805.11600
Bernardo Araneda
Bernardo Araneda
Conformal invariance, complex structures, and the Teukolsky connection
24 pages
null
10.1088/1361-6382/aad13b
null
gr-qc math.DG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show that the Teukolsky connection, which defines generalized wave operators governing the behavior of massless fields on Einstein spacetimes of Petrov type D, has its origin in a distinguished conformally and GHP covariant connection on the conformal structure of the spacetime. The conformal class has a (metric c...
[ { "created": "Tue, 29 May 2018 17:38:31 GMT", "version": "v1" } ]
2018-08-08
[ [ "Araneda", "Bernardo", "" ] ]
We show that the Teukolsky connection, which defines generalized wave operators governing the behavior of massless fields on Einstein spacetimes of Petrov type D, has its origin in a distinguished conformally and GHP covariant connection on the conformal structure of the spacetime. The conformal class has a (metric com...
2312.15457
Pierre-Alexandre Duverne
Pierre-Alexandre Duverne and St\'ephanie Hoang and Tito Dal Canton and Sarah Antier and Nicolas Arnaud and Patrice Hello and Francesco Pannarale
Optimizing the low-latency localization of gravitational waves
12 pages, 9 figures
null
null
null
gr-qc
http://creativecommons.org/licenses/by/4.0/
Gravitational-wave data from interferometric detectors like LIGO, Virgo and KAGRA is routinely analyzed by rapid matched-filtering algorithms to detect compact binary merger events and rapidly infer their spatial position, which enables the discovery of associated non-GW transients like GRB 170817A and AT2017gfo. One...
[ { "created": "Sun, 24 Dec 2023 10:51:50 GMT", "version": "v1" } ]
2023-12-27
[ [ "Duverne", "Pierre-Alexandre", "" ], [ "Hoang", "Stéphanie", "" ], [ "Canton", "Tito Dal", "" ], [ "Antier", "Sarah", "" ], [ "Arnaud", "Nicolas", "" ], [ "Hello", "Patrice", "" ], [ "Pannarale", "Francesco", ...
Gravitational-wave data from interferometric detectors like LIGO, Virgo and KAGRA is routinely analyzed by rapid matched-filtering algorithms to detect compact binary merger events and rapidly infer their spatial position, which enables the discovery of associated non-GW transients like GRB 170817A and AT2017gfo. One o...
0809.1480
Dong-han Yeom
Sungwook E. Hong, Dong-il Hwang, Dong-han Yeom, Heeseung Zoe
Black hole complementarity with local horizons and Horowitz-Maldacena's proposal
22 pages, 11 figures
JHEP 0812:080,2008
10.1088/1126-6708/2008/12/080
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
To implement the consistent black hole complementarity principle, we need two assumptions: first, there exists a singularity near the center, and second, global horizons are the same as local horizons. However, these assumptions are not true in general. In this paper, the authors study a charged black hole in which t...
[ { "created": "Tue, 9 Sep 2008 07:25:22 GMT", "version": "v1" }, { "created": "Tue, 11 Nov 2008 09:02:21 GMT", "version": "v2" }, { "created": "Fri, 19 Dec 2008 08:05:47 GMT", "version": "v3" } ]
2008-12-25
[ [ "Hong", "Sungwook E.", "" ], [ "Hwang", "Dong-il", "" ], [ "Yeom", "Dong-han", "" ], [ "Zoe", "Heeseung", "" ] ]
To implement the consistent black hole complementarity principle, we need two assumptions: first, there exists a singularity near the center, and second, global horizons are the same as local horizons. However, these assumptions are not true in general. In this paper, the authors study a charged black hole in which the...
gr-qc/0701039
Hiroyuki Nakano
Hiroyuki Nakano, Carlos O. Lousto
Regular second order perturbations of extreme mass ratio black hole binaries
4 pages, prepared for the proceedings of the 16th workshop on general relativity and gravitation, Niigata, Japan, Nov.27 - Dec.1, 2006
null
null
null
gr-qc
null
We report on the first results of self-consistent second order metric perturbations produced by a point particle moving in the Schwarzschild spacetime. The second order waveforms satisfy a wave equation with an effective source term build up from products of first order metric perturbations and its derivatives. We ha...
[ { "created": "Fri, 5 Jan 2007 20:49:25 GMT", "version": "v1" } ]
2007-05-23
[ [ "Nakano", "Hiroyuki", "" ], [ "Lousto", "Carlos O.", "" ] ]
We report on the first results of self-consistent second order metric perturbations produced by a point particle moving in the Schwarzschild spacetime. The second order waveforms satisfy a wave equation with an effective source term build up from products of first order metric perturbations and its derivatives. We have...
1407.4103
Shahram Jalalzadeh
Mostafa Hashemi, Shahram Jalalzadeh and Amir Hadi Ziaie
Collapse and dispersal of a homogeneous spin fluid in Einstein-Cartan theory
16 pages, 5 figures, revised version
Eur. Phys. J. C (2015) 75:53
10.1140/epjc/s10052-015-3276-1
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In the present work, we revisit the process of gravitational collapse of a spherically symmetric homogeneous dust fluid which is known as the Oppenheimer-Snyder (OS) model [1]. We show that such a scenario would not end in a spacetime singularity when the spin degrees of freedom of fermionic particles within the coll...
[ { "created": "Tue, 15 Jul 2014 19:31:16 GMT", "version": "v1" }, { "created": "Tue, 24 Feb 2015 10:19:58 GMT", "version": "v2" } ]
2015-02-25
[ [ "Hashemi", "Mostafa", "" ], [ "Jalalzadeh", "Shahram", "" ], [ "Ziaie", "Amir Hadi", "" ] ]
In the present work, we revisit the process of gravitational collapse of a spherically symmetric homogeneous dust fluid which is known as the Oppenheimer-Snyder (OS) model [1]. We show that such a scenario would not end in a spacetime singularity when the spin degrees of freedom of fermionic particles within the collap...
1507.06661
John D. Swain
A. Widom, J. Swain, and Y. Srivastava
Experimental Tests of Local Cosmological Expansion Rates
Presented on July 17, 2015 at the 14th Marcel Grossmann International Conference held at Sapienza, University of Rome, Italy (To appear in the Proceedings of the Conference); reformatted for the proceedings but with the same content
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Cosmological expansion on a local scale is usually neglected in part due to its smallness, and in part due to components of bound systems (especially those bound by non-gravitational forces such as atoms and nuclei) not following the geodesics of the cosmological metric. However, it is interesting to ask whether or n...
[ { "created": "Fri, 17 Jul 2015 18:56:40 GMT", "version": "v1" }, { "created": "Sat, 3 Oct 2015 18:41:04 GMT", "version": "v2" } ]
2015-10-06
[ [ "Widom", "A.", "" ], [ "Swain", "J.", "" ], [ "Srivastava", "Y.", "" ] ]
Cosmological expansion on a local scale is usually neglected in part due to its smallness, and in part due to components of bound systems (especially those bound by non-gravitational forces such as atoms and nuclei) not following the geodesics of the cosmological metric. However, it is interesting to ask whether or not...
1910.03300
Charles Wang
Charles H.-T. Wang, Marcin Stankiewicz
Quantization of time and the big bang via scale-invariant loop gravity
7 pages, 4 figures, version to appear in PLB
Physics Letters B 800 (2020) 135106
10.1016/j.physletb.2019.135106
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider the background-independent quantization of a general scale-invariant theory of gravity with matter, which supports a conserved Weyl current recently suggested as a natural flow of time. For scalar-metric systems, a conformal class of Ashtekar-Barbero connection variables is constructed, which can be quant...
[ { "created": "Tue, 8 Oct 2019 09:42:54 GMT", "version": "v1" }, { "created": "Wed, 13 Nov 2019 16:46:47 GMT", "version": "v2" } ]
2019-11-21
[ [ "Wang", "Charles H. -T.", "" ], [ "Stankiewicz", "Marcin", "" ] ]
We consider the background-independent quantization of a general scale-invariant theory of gravity with matter, which supports a conserved Weyl current recently suggested as a natural flow of time. For scalar-metric systems, a conformal class of Ashtekar-Barbero connection variables is constructed, which can be quantiz...
2008.00429
Manu Srivastava
Manu Srivastava, S. Shankaranarayanan (Indian Institute of Technology Bombay)
Non-trivial quantum fluctuations in asymptotically non-flat black-hole space-times
29 pages, 8 figures, version accepted for publication in Annals of Physics
null
null
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Hawking radiation remains a crucial theoretical prediction of semi-classical gravity and is considered one of the critical tests for a model of quantum gravity. However, Hawking's original derivation used quantum field theory on a fixed background. Efforts have been made to include the spacetime fluctuations arising ...
[ { "created": "Sun, 2 Aug 2020 07:55:33 GMT", "version": "v1" }, { "created": "Tue, 1 Mar 2022 03:32:08 GMT", "version": "v2" } ]
2022-03-02
[ [ "Srivastava", "Manu", "", "Indian Institute of Technology\n Bombay" ], [ "Shankaranarayanan", "S.", "", "Indian Institute of Technology\n Bombay" ] ]
Hawking radiation remains a crucial theoretical prediction of semi-classical gravity and is considered one of the critical tests for a model of quantum gravity. However, Hawking's original derivation used quantum field theory on a fixed background. Efforts have been made to include the spacetime fluctuations arising fr...
2304.07496
Junji Jia
Yujie Duan, Siyan Lin, Junji Jia
Deflection and gravitational lensing with finite distance effect in the strong deflection limit in stationary and axisymmetric spacetimes
15 pages, 10 figures; updated to publish version
null
10.1088/1475-7516/2023/07/036
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the deflection and gravitational lensing (GL) of both timelike and null signals in the equatorial plane of arbitrary stationary and axisymmetric spacetimes in the strong deflection limit. Our approach employs a perturbative method to show that both the deflection angle and the total travel time take quasi-se...
[ { "created": "Sat, 15 Apr 2023 07:33:51 GMT", "version": "v1" }, { "created": "Thu, 13 Jul 2023 06:59:02 GMT", "version": "v2" } ]
2023-07-19
[ [ "Duan", "Yujie", "" ], [ "Lin", "Siyan", "" ], [ "Jia", "Junji", "" ] ]
We study the deflection and gravitational lensing (GL) of both timelike and null signals in the equatorial plane of arbitrary stationary and axisymmetric spacetimes in the strong deflection limit. Our approach employs a perturbative method to show that both the deflection angle and the total travel time take quasi-seri...
2010.00298
Spiros Cotsakis
Spiros Cotsakis
Onset of synchronization in coupled Mixmaster oscillators
40 pages, version to appear in the Phil. Trans. Roy. Soc. A
Phil. Trans. R. Soc. A380 (2022) 20210189
10.1098/rsta.2021.0189
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider the problem of asymptotic synchronization of different spatial points coupled to each other in inhomogeneous spacetime and undergoing chaotic Mixmaster oscillations towards the singularity. We demonstrate that for couplings larger than some threshold value, two Mixmaster spatial points $A,B$, with $A$ in ...
[ { "created": "Thu, 1 Oct 2020 10:58:06 GMT", "version": "v1" }, { "created": "Tue, 22 Jun 2021 10:11:39 GMT", "version": "v2" }, { "created": "Mon, 19 Jul 2021 11:09:29 GMT", "version": "v3" } ]
2022-03-16
[ [ "Cotsakis", "Spiros", "" ] ]
We consider the problem of asymptotic synchronization of different spatial points coupled to each other in inhomogeneous spacetime and undergoing chaotic Mixmaster oscillations towards the singularity. We demonstrate that for couplings larger than some threshold value, two Mixmaster spatial points $A,B$, with $A$ in th...
1003.4851
Manuel Tessmer
Manuel Tessmer
Circular inspiral templates
3 pages, 1 table
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Recently, a new class of restricted gravitational wave search templates, termed the TaylorEt template was proposed for the search of inspiralling compact binaries. The TaylorEt approximant is different from the usual time-domain post-Newtonian approximants in that it employs the orbital binding energy rather than the...
[ { "created": "Thu, 25 Mar 2010 10:46:39 GMT", "version": "v1" } ]
2010-03-26
[ [ "Tessmer", "Manuel", "" ] ]
Recently, a new class of restricted gravitational wave search templates, termed the TaylorEt template was proposed for the search of inspiralling compact binaries. The TaylorEt approximant is different from the usual time-domain post-Newtonian approximants in that it employs the orbital binding energy rather than the o...
1907.03578
David Garfinkle
David Garfinkle
Matters of Gravity: The Newsletter of the Division of Gravitational Physics of the American Physical Society. Number 53. June, 2019
null
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
we hear that..., by David Garfinkle Gravitational-wave Standard Sirens, by Daniel Holz and Maya Fishbach HartleFest, by Gary Horowitz
[ { "created": "Wed, 3 Jul 2019 20:22:34 GMT", "version": "v1" } ]
2019-07-09
[ [ "Garfinkle", "David", "" ] ]
we hear that..., by David Garfinkle Gravitational-wave Standard Sirens, by Daniel Holz and Maya Fishbach HartleFest, by Gary Horowitz
2008.04106
Ritabrata Biswas
Giridhari Deogharia, Mayukh Bandyopadhyay and Ritabrata Biswas
Generalized Model of Interacting Dark Energy and Dark Matter : Phase Portrait Analysis of Evolving Universe
12 page, 12 figures
null
10.1142/S0217732321502758
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Main aim of this work is to give a suitable explanation of present accelerating universe through an acceptable interactive dynamical cosmological model. A three-fluid cosmological model is introduced in the background of Friedmann-Lema\^itre-Robertson-Walker asymptotically flat spacetime. This model consists of inter...
[ { "created": "Thu, 6 Aug 2020 18:14:55 GMT", "version": "v1" } ]
2022-02-16
[ [ "Deogharia", "Giridhari", "" ], [ "Bandyopadhyay", "Mayukh", "" ], [ "Biswas", "Ritabrata", "" ] ]
Main aim of this work is to give a suitable explanation of present accelerating universe through an acceptable interactive dynamical cosmological model. A three-fluid cosmological model is introduced in the background of Friedmann-Lema\^itre-Robertson-Walker asymptotically flat spacetime. This model consists of interac...
1705.02533
Andrew DeBenedictis
Jesse Velay-Vitow, Andrew DeBenedictis
Junction Conditions for F(T) Gravity from a Variational Principle
14 pages, 1 figure. Updated version contains clarification on the role of the spin connection and a number of added references. Matches version accepted for publication in Phys. Rev. D
Phys. Rev. D 96, 024055 (2017)
10.1103/PhysRevD.96.024055
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We derive a general set of acceptable junction conditions for $F(T)$ gravity via the variational principle. The analysis is valid for both the traditional form of $F(T)$ gravity theory as well as the more recently introduced Lorentz covariant theory of Kr\v{s}\v{s}\'ak and Saridakis. We find that the general junction...
[ { "created": "Sat, 6 May 2017 23:06:15 GMT", "version": "v1" }, { "created": "Fri, 14 Jul 2017 18:22:06 GMT", "version": "v2" } ]
2017-07-31
[ [ "Velay-Vitow", "Jesse", "" ], [ "DeBenedictis", "Andrew", "" ] ]
We derive a general set of acceptable junction conditions for $F(T)$ gravity via the variational principle. The analysis is valid for both the traditional form of $F(T)$ gravity theory as well as the more recently introduced Lorentz covariant theory of Kr\v{s}\v{s}\'ak and Saridakis. We find that the general junction c...
1703.06265
Nosiphiwo Zwane Ms
Nosiphiwo Zwane, Niayesh Afshordi and Rafael D. Sorkin
Cosmological Tests of Everpresent $\Lambda$
null
null
10.1088/1361-6382/aadc36
null
gr-qc astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Everpresent $\Lambda$ is a cosmological scenario in which the observed cosmological "constant" $\Lambda$ fluctuates between positive and negative values with a vanishing mean, and with a magnitude comparable to the critical density at any epoch. In accord with a longstanding heuristic prediction of causal set theory,...
[ { "created": "Sat, 18 Mar 2017 07:47:23 GMT", "version": "v1" }, { "created": "Tue, 27 Jun 2017 07:09:57 GMT", "version": "v2" }, { "created": "Fri, 30 Jun 2017 03:25:38 GMT", "version": "v3" }, { "created": "Tue, 22 May 2018 22:54:36 GMT", "version": "v4" } ]
2018-10-17
[ [ "Zwane", "Nosiphiwo", "" ], [ "Afshordi", "Niayesh", "" ], [ "Sorkin", "Rafael D.", "" ] ]
Everpresent $\Lambda$ is a cosmological scenario in which the observed cosmological "constant" $\Lambda$ fluctuates between positive and negative values with a vanishing mean, and with a magnitude comparable to the critical density at any epoch. In accord with a longstanding heuristic prediction of causal set theory, i...
1904.06207
Cosimo Bambi
Askar B. Abdikamalov, Ahmadjon A. Abdujabbarov, Dimitry Ayzenberg, Daniele Malafarina, Cosimo Bambi, Bobomurat Ahmedov
Black hole mimicker hiding in the shadow: Optical properties of the $\gamma$-metric
12 pages, 7 figures. v3: refereed version
Phys. Rev. D 100, 024014 (2019)
10.1103/PhysRevD.100.024014
null
gr-qc astro-ph.HE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Can the observation of the "shadow" allow us to distinguish a black hole from a more exotic compact object? We study the motion of photons in a class of vacuum static axially-symmetric space-times that is continuously linked to the Schwarzschild metric through the value of one parameter that can be interpreted as a m...
[ { "created": "Thu, 11 Apr 2019 12:47:12 GMT", "version": "v1" }, { "created": "Thu, 18 Apr 2019 16:49:06 GMT", "version": "v2" }, { "created": "Wed, 10 Jul 2019 22:38:50 GMT", "version": "v3" } ]
2019-07-12
[ [ "Abdikamalov", "Askar B.", "" ], [ "Abdujabbarov", "Ahmadjon A.", "" ], [ "Ayzenberg", "Dimitry", "" ], [ "Malafarina", "Daniele", "" ], [ "Bambi", "Cosimo", "" ], [ "Ahmedov", "Bobomurat", "" ] ]
Can the observation of the "shadow" allow us to distinguish a black hole from a more exotic compact object? We study the motion of photons in a class of vacuum static axially-symmetric space-times that is continuously linked to the Schwarzschild metric through the value of one parameter that can be interpreted as a mea...
gr-qc/0703155
Chris Messenger
C. Messenger and G. Woan
A fast search strategy for gravitational waves from low-mass X-ray binaries
13 pages, 3 figures, to appear in the GWDAW 11 conference proceedings
Class.Quant.Grav.24:S469-S480,2007
10.1088/0264-9381/24/19/S10
null
gr-qc
null
We present a new type of search strategy designed specifically to find continuously emitting gravitational wave sources in known binary systems based on the incoherent sum of frequency modulated binary signal sidebands. The search pipeline can be divided into three stages: the first is a wide bandwidth, F-statistic s...
[ { "created": "Fri, 30 Mar 2007 16:51:40 GMT", "version": "v1" }, { "created": "Mon, 2 Apr 2007 16:01:16 GMT", "version": "v2" } ]
2008-11-26
[ [ "Messenger", "C.", "" ], [ "Woan", "G.", "" ] ]
We present a new type of search strategy designed specifically to find continuously emitting gravitational wave sources in known binary systems based on the incoherent sum of frequency modulated binary signal sidebands. The search pipeline can be divided into three stages: the first is a wide bandwidth, F-statistic sea...
0710.3565
Parampreet Singh
Abhay Ashtekar, Alejandro Corichi, Parampreet Singh
Robustness of key features of loop quantum cosmology
Two changes from the published version: (1) Use of the scalar field clock already in the classical theory leads to a soluble model without any assumptions. sLQC now stands for soluble (rather than simplified) LQC; (2) Some intermediate steps corrected, thanks to a comment by Prof. Ian Lawrie. This also simplifi...
Phys.Rev.D77:024046,2008
10.1103/PhysRevD.77.024046
IGC-07/10-01, PI-QG-61
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Loop quantum cosmology of the k=0 FRW model (with a massless scalar field) is shown to be exactly soluble if the scalar field is used as the internal time already in the classical Hamiltonian theory. Analytical methods are then used i) to show that the quantum bounce is generic; ii) to establish that the matter densi...
[ { "created": "Thu, 18 Oct 2007 17:38:57 GMT", "version": "v1" }, { "created": "Thu, 22 Nov 2007 00:12:43 GMT", "version": "v2" }, { "created": "Thu, 24 Jan 2008 17:34:01 GMT", "version": "v3" }, { "created": "Thu, 22 Apr 2010 16:43:46 GMT", "version": "v4" } ]
2010-04-23
[ [ "Ashtekar", "Abhay", "" ], [ "Corichi", "Alejandro", "" ], [ "Singh", "Parampreet", "" ] ]
Loop quantum cosmology of the k=0 FRW model (with a massless scalar field) is shown to be exactly soluble if the scalar field is used as the internal time already in the classical Hamiltonian theory. Analytical methods are then used i) to show that the quantum bounce is generic; ii) to establish that the matter density...
2111.02282
Theo Torres
Theo Torres
Hydrodynamic simulations of rotating black holes
PhD thesis - 187 pages
null
null
null
gr-qc physics.flu-dyn
http://creativecommons.org/licenses/by/4.0/
Wave scattering phenomena are ubiquitous in almost all Sciences, from Biology to Physics. Interestingly, it has been shown many times that different physical systems are the stage to the same processes. The discoveries of such analogies have resulted in a better understanding of Physics and are indications of the uni...
[ { "created": "Wed, 3 Nov 2021 15:17:32 GMT", "version": "v1" } ]
2021-11-04
[ [ "Torres", "Theo", "" ] ]
Wave scattering phenomena are ubiquitous in almost all Sciences, from Biology to Physics. Interestingly, it has been shown many times that different physical systems are the stage to the same processes. The discoveries of such analogies have resulted in a better understanding of Physics and are indications of the unive...
gr-qc/0211106
Hendryk Pfeiffer
Hendryk Pfeiffer
Positivity of relativistic spin network evaluations
15 pages, LaTeX2e, 8 figures
Adv.Theor.Math.Phys. 6 (2002) 827-846
null
null
gr-qc
null
Let G be a compact Lie group. Using suitable normalization conventions, we show that the evaluation of GxG-symmetric spin networks is non-negative whenever the edges are labeled by representations of the form V\otimes V^* where V is a representation of G, and the intertwiners are generalizations of the Barrett--Crane...
[ { "created": "Fri, 29 Nov 2002 16:24:13 GMT", "version": "v1" }, { "created": "Fri, 2 Jan 2004 16:23:13 GMT", "version": "v2" } ]
2007-05-23
[ [ "Pfeiffer", "Hendryk", "" ] ]
Let G be a compact Lie group. Using suitable normalization conventions, we show that the evaluation of GxG-symmetric spin networks is non-negative whenever the edges are labeled by representations of the form V\otimes V^* where V is a representation of G, and the intertwiners are generalizations of the Barrett--Crane i...
0909.2578
Raphael Lamon
Raphael Lamon
Loop Quantum Cosmology on a Torus
35 pages, 7 figures
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we study the effect of a torus topology on Loop Quantum Cosmology. We first derive the Teichmueller space parametrizing all possible tori using Thurston's theorem and construct a Hamiltonian describing the dynamics of these torus universes. We then compute the Ashtekar variables for a slightly simplifie...
[ { "created": "Mon, 14 Sep 2009 15:34:05 GMT", "version": "v1" } ]
2009-09-15
[ [ "Lamon", "Raphael", "" ] ]
In this paper we study the effect of a torus topology on Loop Quantum Cosmology. We first derive the Teichmueller space parametrizing all possible tori using Thurston's theorem and construct a Hamiltonian describing the dynamics of these torus universes. We then compute the Ashtekar variables for a slightly simplified ...
gr-qc/0101042
Fay Dowker
H.F. Dowker and R.D. Sorkin
Spin and statistics in quantum gravity
14 pages, 4 figures, LaTeX
Proceedings of the international meeting on ``Spin-statistics connections and commutation relations, experimental tests and theoretical implications,'' Capri, Italy, May 31-June 4, 2000, eds. R.C. Hilborn and G.M. Tino, pp. 205-218
null
null
gr-qc
null
We present a review of the spin and statistics of topological geons, particles in 3+1 quantum gravity. They can have half-odd-integral spin and fermionic statistics and since the underlying gravitational field is tensorial and bosonic, this is an example of ``emergent'' non-trivial spin and statistics as displayed by...
[ { "created": "Thu, 11 Jan 2001 12:49:45 GMT", "version": "v1" } ]
2007-05-23
[ [ "Dowker", "H. F.", "" ], [ "Sorkin", "R. D.", "" ] ]
We present a review of the spin and statistics of topological geons, particles in 3+1 quantum gravity. They can have half-odd-integral spin and fermionic statistics and since the underlying gravitational field is tensorial and bosonic, this is an example of ``emergent'' non-trivial spin and statistics as displayed by f...
2004.04506
Christof Wetterich
C. Wetterich
Crossing the Big Bang singularity
further precisions on inhomogeneous cosmologies, 11 pages
null
null
null
gr-qc astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A simple model for a scalar field and gravity admits homogeneous isotropic cosmological solutions which cross the Big Bang singularity. In the scaling frame with field dependent effective Planck mass these solutions are regular. They become singular in the Einstein frame with fixed Planck mass. This field singularity...
[ { "created": "Thu, 9 Apr 2020 12:06:46 GMT", "version": "v1" }, { "created": "Wed, 29 Apr 2020 10:28:26 GMT", "version": "v2" }, { "created": "Mon, 26 Oct 2020 11:46:17 GMT", "version": "v3" }, { "created": "Mon, 26 Jul 2021 16:14:12 GMT", "version": "v4" } ]
2021-07-27
[ [ "Wetterich", "C.", "" ] ]
A simple model for a scalar field and gravity admits homogeneous isotropic cosmological solutions which cross the Big Bang singularity. In the scaling frame with field dependent effective Planck mass these solutions are regular. They become singular in the Einstein frame with fixed Planck mass. This field singularity a...
1805.03440
Oleg Zaslavskii
O. B. Zaslavskii
Distorted vacuum black holes in the canonical ensemble
6 pages. Eq. 8 written more accurately. Matches published version
Mod. Phys. Lett. A, Vol. 34, Nos. 7 & 8 (2019) 1950060
10.1142/S0217732319500603
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider a vacuum static spacetime in a finite size cavity. On the boundary, we specify a metric and a finite constant local temperature $T$. No spherical or any other spatial symmetry is assumed. We show that (i) inside a cavity, only a black hole or flat spacetime are possible, whereas a curved horizonless regul...
[ { "created": "Wed, 9 May 2018 10:03:12 GMT", "version": "v1" }, { "created": "Thu, 21 Mar 2019 11:06:12 GMT", "version": "v2" } ]
2019-03-27
[ [ "Zaslavskii", "O. B.", "" ] ]
We consider a vacuum static spacetime in a finite size cavity. On the boundary, we specify a metric and a finite constant local temperature $T$. No spherical or any other spatial symmetry is assumed. We show that (i) inside a cavity, only a black hole or flat spacetime are possible, whereas a curved horizonless regular...
1906.01979
Jose Alejandro Rosabal Rodriguez
J.A. Rosabal
Rindler Observer Sublimation
25 pages, 7 figures, matches the published version
JMP Vol.11 No.9, September 22, 2020
10.4236/jmp.2020.119086
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this note, we propose that an object moving with proper constant acceleration, i.e., a Rindler observer experiences a sublimation (or evaporation) process. In this first proposal, we do not consider the backreaction due to the sublimation. We focus on charged matter particles for the discussion, but for simplicity...
[ { "created": "Sun, 2 Jun 2019 05:59:28 GMT", "version": "v1" }, { "created": "Fri, 14 Jun 2019 04:47:57 GMT", "version": "v2" }, { "created": "Wed, 7 Oct 2020 08:45:36 GMT", "version": "v3" } ]
2020-10-08
[ [ "Rosabal", "J. A.", "" ] ]
In this note, we propose that an object moving with proper constant acceleration, i.e., a Rindler observer experiences a sublimation (or evaporation) process. In this first proposal, we do not consider the backreaction due to the sublimation. We focus on charged matter particles for the discussion, but for simplicity, ...
2203.05270
Vitalii Vertogradov
Vitalii Vertogradov
Non-linearity of Vaidya spacetime and forces in the central naked singularity
null
Physics of Complex Systems, 2022, vol. 3, no. 2
10.33910/2687-153X-2022-3-2-81-85
null
gr-qc
http://creativecommons.org/licenses/by/4.0/
In this paper we consider non-linear Vaidya spacetime i.e. the case when the mass function has the non-linear form $M(v) \equiv \lambda v^n \,, \lambda >0 \,, n>1 $. We prove that the central naked singularity might form for values $n>1$ but they are gravitationally weak. Also we investigate the question about forces...
[ { "created": "Thu, 10 Mar 2022 10:06:47 GMT", "version": "v1" }, { "created": "Wed, 7 Dec 2022 14:08:29 GMT", "version": "v2" } ]
2022-12-08
[ [ "Vertogradov", "Vitalii", "" ] ]
In this paper we consider non-linear Vaidya spacetime i.e. the case when the mass function has the non-linear form $M(v) \equiv \lambda v^n \,, \lambda >0 \,, n>1 $. We prove that the central naked singularity might form for values $n>1$ but they are gravitationally weak. Also we investigate the question about forces i...
1711.01899
Yosef Verbin
Y. Verbin and Y. Brihaye
Charged Boson Stars and Black Holes with Non-Minimal Coupling to Gravity
Revised version. Accepted for publication in Phys Rev D
Phys. Rev. D 97, 044046 (2018)
10.1103/PhysRevD.97.044046
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We find new spherically symmetric charged boson star solutions of a complex scalar field coupled non-minimally to gravity by a "John-type" term of Horndeski theory, that is a coupling between the kinetic scalar term and Einstein tensor. We study the parameter space of the solutions and find two distinct families acco...
[ { "created": "Mon, 6 Nov 2017 14:04:47 GMT", "version": "v1" }, { "created": "Mon, 13 Nov 2017 15:30:26 GMT", "version": "v2" }, { "created": "Tue, 13 Feb 2018 14:39:19 GMT", "version": "v3" } ]
2018-03-07
[ [ "Verbin", "Y.", "" ], [ "Brihaye", "Y.", "" ] ]
We find new spherically symmetric charged boson star solutions of a complex scalar field coupled non-minimally to gravity by a "John-type" term of Horndeski theory, that is a coupling between the kinetic scalar term and Einstein tensor. We study the parameter space of the solutions and find two distinct families accord...
gr-qc/0007046
Folomeev V. N.
V. Ts. Gurovich, H.-J. Schmidt and I. V. Tokareva
Tunneling of the Closed Friedmann Universe with Generation of Scalar Waves
Latex 2e, 7 pages, 1 figure. Submitted to General Relativity and Gravitation
Gen.Rel.Grav. 33 (2001) 591-601
10.1023/A:1010253025941
null
gr-qc
null
The evolution of the closed Friedmann Universe with a packet of short scalar waves is considered with the help of the Wheeler--DeWitt equation. The packet ensures conservation of homogeneity and isotropy of the metric on average. It is shown that during tunneling the amplitudes of short waves of a scalar field can in...
[ { "created": "Wed, 19 Jul 2000 10:12:27 GMT", "version": "v1" } ]
2015-06-25
[ [ "Gurovich", "V. Ts.", "" ], [ "Schmidt", "H. -J.", "" ], [ "Tokareva", "I. V.", "" ] ]
The evolution of the closed Friedmann Universe with a packet of short scalar waves is considered with the help of the Wheeler--DeWitt equation. The packet ensures conservation of homogeneity and isotropy of the metric on average. It is shown that during tunneling the amplitudes of short waves of a scalar field can incr...
gr-qc/0504036
Kayll Lake
Steven Conboy and Kayll Lake
Smooth transitions from Schwarzschild vacuum to de Sitter space
revtex4, two figures. Final form to appear in Phys. Rev. D
Phys.Rev. D71 (2005) 124017
10.1103/PhysRevD.71.124017
null
gr-qc
null
We provide an infinity of spacetimes which contain part of both the Schwarzschild vacuum and de Sitter space. The transition, which occurs below the Schwarzschild event horizon, involves only boundary surfaces (no surface layers). An explicit example is given in which the weak and strong energy conditions are satisfi...
[ { "created": "Fri, 8 Apr 2005 16:39:55 GMT", "version": "v1" }, { "created": "Thu, 14 Apr 2005 19:35:22 GMT", "version": "v2" }, { "created": "Fri, 27 May 2005 14:30:09 GMT", "version": "v3" } ]
2009-11-11
[ [ "Conboy", "Steven", "" ], [ "Lake", "Kayll", "" ] ]
We provide an infinity of spacetimes which contain part of both the Schwarzschild vacuum and de Sitter space. The transition, which occurs below the Schwarzschild event horizon, involves only boundary surfaces (no surface layers). An explicit example is given in which the weak and strong energy conditions are satisfied...
1707.01784
Gabriel G. Carvalho PhD
Iarley P. Lobo and Gabriel G. Carvalho
The geometry of null-like disformal transformations
Accepted for publication in IJGMMP. 24 pages, 2 figures.Typos corrected, figures updated and addition of an appendix on disformal transformations on spinor space
null
10.1142/S0219887819501809
null
gr-qc math-ph math.MP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Motivated by the hindrance of defining metric tensors compatible with the underlying spinor structure, other than the ones obtained via a conformal transformation, we study how some geometric objects are affected by the action of a disformal transformation in the closest scenario possible: the disformal transformatio...
[ { "created": "Thu, 6 Jul 2017 13:40:46 GMT", "version": "v1" }, { "created": "Sat, 12 Oct 2019 12:03:32 GMT", "version": "v2" } ]
2019-10-15
[ [ "Lobo", "Iarley P.", "" ], [ "Carvalho", "Gabriel G.", "" ] ]
Motivated by the hindrance of defining metric tensors compatible with the underlying spinor structure, other than the ones obtained via a conformal transformation, we study how some geometric objects are affected by the action of a disformal transformation in the closest scenario possible: the disformal transformation ...
1503.02832
Orlando Luongo
Salvatore Capozziello, Orlando Luongo, Emmanuel N. Saridakis
Transition redshift in $f(T)$ cosmology and observational constraints
11 pages, 1 table, 7 figures
Phys. Rev. D, 91, 124037, (2015)
null
null
gr-qc astro-ph.CO hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We extract constraints on the transition redshift $z_{tr}$, determining the onset of cosmic acceleration, predicted by an effective cosmographic construction, in the framework of $f(T)$ gravity. In particular, employing cosmography we obtain bounds on the viable $f(T)$ forms and their derivatives. Since this procedur...
[ { "created": "Tue, 10 Mar 2015 09:45:29 GMT", "version": "v1" }, { "created": "Thu, 18 Jun 2015 07:00:28 GMT", "version": "v2" } ]
2015-06-19
[ [ "Capozziello", "Salvatore", "" ], [ "Luongo", "Orlando", "" ], [ "Saridakis", "Emmanuel N.", "" ] ]
We extract constraints on the transition redshift $z_{tr}$, determining the onset of cosmic acceleration, predicted by an effective cosmographic construction, in the framework of $f(T)$ gravity. In particular, employing cosmography we obtain bounds on the viable $f(T)$ forms and their derivatives. Since this procedure ...
1904.02299
Belinka Gonz\'alez-Fern\'andez Dr.
B. Gonz\'alez-Fern\'andez and A. Camacho
Accelerated observers emerging from a Bose-Einstein condensate through analogue gravity
13 pages
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The current article explores the problem of a Bose-Einstein condensate (BEC) trapped in an anisotropic three-dimensional harmonic-oscillator potential, with positive effective interatomic interactions, and the analogue gravity acoustic metric emerging from it. We find that the latter gives rise to a family of conform...
[ { "created": "Thu, 4 Apr 2019 01:31:41 GMT", "version": "v1" } ]
2019-04-05
[ [ "González-Fernández", "B.", "" ], [ "Camacho", "A.", "" ] ]
The current article explores the problem of a Bose-Einstein condensate (BEC) trapped in an anisotropic three-dimensional harmonic-oscillator potential, with positive effective interatomic interactions, and the analogue gravity acoustic metric emerging from it. We find that the latter gives rise to a family of conformal...
gr-qc/0601084
Serena Fagnocchi
S. Fagnocchi
Back-reaction effects in acoustic black holes
10 pages, 1 figure; Talk given at the conference ``Constrained Dynamics and Quantum Gravity (QG05)", Cala Gonone (Italy), September 2005
J.Phys.Conf.Ser. 33 (2006) 445-450
10.1088/1742-6596/33/1/057
null
gr-qc cond-mat.other hep-th
null
Acoustic black holes are very interesting non-gravitational objects which can be described by the geometrical formalism of General Relativity. These models can be useful to experimentally test effects otherwise undetectable, as for example the Hawking radiation. The back-reaction effects on the background quantities ...
[ { "created": "Fri, 20 Jan 2006 14:28:42 GMT", "version": "v1" } ]
2015-06-25
[ [ "Fagnocchi", "S.", "" ] ]
Acoustic black holes are very interesting non-gravitational objects which can be described by the geometrical formalism of General Relativity. These models can be useful to experimentally test effects otherwise undetectable, as for example the Hawking radiation. The back-reaction effects on the background quantities in...
gr-qc/9905093
Sibiryakov
V.A.Rubakov, S.M.Sibiryakov
False vacuum decay in de Sitter space-time
26 pages,10 figures
Theor.Math.Phys. 120 (1999) 1194-1212; Teor.Mat.Fiz. 120 (1999) 451-472
10.1007/BF02557243
null
gr-qc astro-ph hep-th
null
We suggest a technique that explicitly accounts for the structure of an initial state of quantum field in the semiclassical calculations of path integral in curved space-time, and consider decay of metastable state (conformal vacuum of scalar particles above false classical vacuum) in background de Sitter space-time ...
[ { "created": "Tue, 25 May 1999 17:10:23 GMT", "version": "v1" } ]
2009-10-31
[ [ "Rubakov", "V. A.", "" ], [ "Sibiryakov", "S. M.", "" ] ]
We suggest a technique that explicitly accounts for the structure of an initial state of quantum field in the semiclassical calculations of path integral in curved space-time, and consider decay of metastable state (conformal vacuum of scalar particles above false classical vacuum) in background de Sitter space-time as...
1112.2955
Elena Melkumova
E.Yu. Melkumova
Plasmon-graviton conversion in a magnetic field in TeV-scale gravity
Submitted to Proceedings of "RusGrav-14" International Conference, 27.06-02.07 2011, Ulyanovks, Russia
null
10.1134/S0202289312010112
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Kaluza-Klein (KK) gravitons emission rates due to plasmon-graviton conversion in magnetic field are computed within the ADD model of TeV-scale gravity. Plasma is described in the kinetic approach as the system of charged particles and Maxwell field both confined on the brane. Interaction with multidimensional gravity...
[ { "created": "Tue, 13 Dec 2011 16:49:40 GMT", "version": "v1" } ]
2015-06-03
[ [ "Melkumova", "E. Yu.", "" ] ]
Kaluza-Klein (KK) gravitons emission rates due to plasmon-graviton conversion in magnetic field are computed within the ADD model of TeV-scale gravity. Plasma is described in the kinetic approach as the system of charged particles and Maxwell field both confined on the brane. Interaction with multidimensional gravity l...
gr-qc/9608040
Yoav Peleg
Yoav Peleg, Sukanta Bose, and Leonard Parker (Univ. of Wisconsin, Milwaukee)
Choptuik Scaling and Quantum Effects in 2D Dilaton Gravity
11p RevTex version + 12p uuencoded gzip version including 3 figures
Phys.Rev.D55:4525-4528,1997
10.1103/PhysRevD.55.4525
WISC-MILW-96-TH-22
gr-qc hep-th
null
We study numerically the collapse of massless scalar fields in two-dimensional dilaton gravity, both classically and semiclassically. At the classical level, we find that the black hole mass scales at threshold like $M_{\rm bh} \propto |p-p^*|^{\gamma}$, where $\gamma \simeq 0.53$. At the semiclassical level, we find...
[ { "created": "Fri, 16 Aug 1996 18:12:17 GMT", "version": "v1" } ]
2009-12-30
[ [ "Peleg", "Yoav", "", "Univ. of Wisconsin,\n Milwaukee" ], [ "Bose", "Sukanta", "", "Univ. of Wisconsin,\n Milwaukee" ], [ "Parker", "Leonard", "", "Univ. of Wisconsin,\n Milwaukee" ] ]
We study numerically the collapse of massless scalar fields in two-dimensional dilaton gravity, both classically and semiclassically. At the classical level, we find that the black hole mass scales at threshold like $M_{\rm bh} \propto |p-p^*|^{\gamma}$, where $\gamma \simeq 0.53$. At the semiclassical level, we find t...
gr-qc/0407099
Timoshkin Alexandr V.
Alexandr V. Timoshkin
The asymptotic conformal invariance in Chern-Simons theory with matter in curved space-time
null
TSPU Vestnik 44N7:57-59,2004
null
null
gr-qc
null
We consider the asymptoic behaviour of the Chern - Simons (CS) theory with matter in curved space - time. The asymptotics of effective couplings are discussed.
[ { "created": "Tue, 27 Jul 2004 04:08:50 GMT", "version": "v1" } ]
2009-02-25
[ [ "Timoshkin", "Alexandr V.", "" ] ]
We consider the asymptoic behaviour of the Chern - Simons (CS) theory with matter in curved space - time. The asymptotics of effective couplings are discussed.
1905.04263
Andrea Giusti
Andrea Giusti, Valerio Faraoni
Turnaround size of non-spherical structures
10 pages, no figures
Physics of the Dark Universe 26 (2019) 100353
10.1016/j.dark.2019.100353
null
gr-qc astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The turnaround radius of a large structure in an accelerating universe has been studied only for spherical structures, while real astronomical systems deviate from spherical symmetry. We show that, for small deviations from spherical symmetry, the gauge-invariant characterization of the turnaround size using the Hawk...
[ { "created": "Fri, 10 May 2019 17:07:52 GMT", "version": "v1" }, { "created": "Sun, 14 Jul 2019 07:04:49 GMT", "version": "v2" } ]
2019-07-16
[ [ "Giusti", "Andrea", "" ], [ "Faraoni", "Valerio", "" ] ]
The turnaround radius of a large structure in an accelerating universe has been studied only for spherical structures, while real astronomical systems deviate from spherical symmetry. We show that, for small deviations from spherical symmetry, the gauge-invariant characterization of the turnaround size using the Hawkin...
2403.12555
Pradip Kumar Chattopadhyay Dr.
Debadri Bhattacharjee and Pradip Kumar Chattopadhyay
Impact of non-zero strange quark mass $(m_{s}\neq0)$ in $f(R,T)$ gravity admitting observational results of strange stars
31 pages, 19 figures
null
null
null
gr-qc
http://creativecommons.org/licenses/by-nc-nd/4.0/
In this article we propose a new class of isotropic strange star using Buchdahl-I metric ansatz in the context of MIT bag model equation of state considering of non-zero strange quark mass $(m_{s})$ in the framework of modified $f(R,T)$ theory of gravity. The barotropic form of MIT bag model equation of state and a s...
[ { "created": "Tue, 19 Mar 2024 08:59:13 GMT", "version": "v1" }, { "created": "Tue, 21 May 2024 08:09:11 GMT", "version": "v2" } ]
2024-05-22
[ [ "Bhattacharjee", "Debadri", "" ], [ "Chattopadhyay", "Pradip Kumar", "" ] ]
In this article we propose a new class of isotropic strange star using Buchdahl-I metric ansatz in the context of MIT bag model equation of state considering of non-zero strange quark mass $(m_{s})$ in the framework of modified $f(R,T)$ theory of gravity. The barotropic form of MIT bag model equation of state and a spe...
1409.0469
Michel Tytgat
Guillaume Defillon, Etienne Granet, Petr Tinyakov and Michel H.G. Tytgat
On tidal capture of primordial black holes by neutron stars
7 pages
Phys. Rev. D 90, 103522 (2014)
10.1103/PhysRevD.90.103522
ULB-TH/14-13
gr-qc astro-ph.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The fraction of primordial black holes (PBHs) of masses $10^{17} - 10^{26}$ g in the total amount of dark matter may be constrained by considering their capture by neutron stars (NSs), which leads to the rapid destruction of the latter. The constraints depend crucially on the capture rate which, in turn, is determine...
[ { "created": "Mon, 1 Sep 2014 16:20:10 GMT", "version": "v1" } ]
2014-11-26
[ [ "Defillon", "Guillaume", "" ], [ "Granet", "Etienne", "" ], [ "Tinyakov", "Petr", "" ], [ "Tytgat", "Michel H. G.", "" ] ]
The fraction of primordial black holes (PBHs) of masses $10^{17} - 10^{26}$ g in the total amount of dark matter may be constrained by considering their capture by neutron stars (NSs), which leads to the rapid destruction of the latter. The constraints depend crucially on the capture rate which, in turn, is determined ...
2007.00665
Jose' P. S. Lemos
Jos\'e P. S. Lemos, Oleg B. Zaslavskii
Compact objects in general relativity: From Buchdahl stars to quasiblack holes
25 pages, 7 figures
International Journal of Modern Physics D 29, 2041019 (2020)
10.1142/S0218271820410199
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A Buchdahl star is a highly compact star for which the boundary radius $R$ obeys $R=\frac98 r_+$, where $r_+$ is the gravitational radius of the star itself. A quasiblack hole is a maximum compact star, or more generically a maximum compact object, for which the boundary radius $R$ obeys $R=r_+$. Quasiblack holes are...
[ { "created": "Wed, 1 Jul 2020 18:00:01 GMT", "version": "v1" }, { "created": "Wed, 16 Sep 2020 16:19:24 GMT", "version": "v2" } ]
2020-09-17
[ [ "Lemos", "José P. S.", "" ], [ "Zaslavskii", "Oleg B.", "" ] ]
A Buchdahl star is a highly compact star for which the boundary radius $R$ obeys $R=\frac98 r_+$, where $r_+$ is the gravitational radius of the star itself. A quasiblack hole is a maximum compact star, or more generically a maximum compact object, for which the boundary radius $R$ obeys $R=r_+$. Quasiblack holes are o...
gr-qc/9512009
Gregory B. Cook
Gregory B. Cook, Stuart L. Shapiro, Saul A. Teukolsky
Testing a Simplified Version of Einstein's Equations for Numerical Relativity
9 pages (RevTeX 3.0 with 6 uuencoded figures), CRSR-1079
Phys.Rev. D53 (1996) 5533-5540
10.1103/PhysRevD.53.5533
null
gr-qc
null
Solving dynamical problems in general relativity requires the full machinery of numerical relativity. Wilson has proposed a simpler but approximate scheme for systems near equilibrium, like binary neutron stars. We test the scheme on isolated, rapidly rotating, relativistic stars. Since these objects are in equilibri...
[ { "created": "Tue, 5 Dec 1995 15:17:21 GMT", "version": "v1" } ]
2009-10-28
[ [ "Cook", "Gregory B.", "" ], [ "Shapiro", "Stuart L.", "" ], [ "Teukolsky", "Saul A.", "" ] ]
Solving dynamical problems in general relativity requires the full machinery of numerical relativity. Wilson has proposed a simpler but approximate scheme for systems near equilibrium, like binary neutron stars. We test the scheme on isolated, rapidly rotating, relativistic stars. Since these objects are in equilibrium...
gr-qc/9401002
Roh-Suan Tung
James M. Nester and Roh-Suan Tung
Another positivity proof and gravitational energy localizations
14 pages REVTeX
Phys.Rev.D49:3958-3962,1994
10.1103/PhysRevD.49.3958
null
gr-qc
null
Two locally positive expressions for the gravitational Hamiltonian, one using 4-spinors the other special orthonormal frames, are reviewed. A new quadratic 3-spinor-curvature identity is used to obtain another positive expression for the Hamiltonian and thereby a localization of gravitational energy and positive ener...
[ { "created": "Fri, 7 Jan 1994 00:19:12 GMT", "version": "v1" } ]
2010-11-01
[ [ "Nester", "James M.", "" ], [ "Tung", "Roh-Suan", "" ] ]
Two locally positive expressions for the gravitational Hamiltonian, one using 4-spinors the other special orthonormal frames, are reviewed. A new quadratic 3-spinor-curvature identity is used to obtain another positive expression for the Hamiltonian and thereby a localization of gravitational energy and positive energy...
2311.17817
Daniela Magos
Daniela Magos and Mauricio Bellini
Seminal Electromagnetic fields from preinflation
null
null
10.1016/j.astropartphys.2024.103006
null
gr-qc
http://creativecommons.org/licenses/by/4.0/
We investigate the geometric dynamics of the primordial electric and magnetic fields during the early stages of the universe by extending a recently introduced quantum algebra \cite{BMM,BMAS}. We work on an extended model of gravity that considers the boundary terms from the Einstein-Hilbert action as geometric quant...
[ { "created": "Wed, 29 Nov 2023 17:16:51 GMT", "version": "v1" }, { "created": "Sun, 30 Jun 2024 18:22:09 GMT", "version": "v2" } ]
2024-07-02
[ [ "Magos", "Daniela", "" ], [ "Bellini", "Mauricio", "" ] ]
We investigate the geometric dynamics of the primordial electric and magnetic fields during the early stages of the universe by extending a recently introduced quantum algebra \cite{BMM,BMAS}. We work on an extended model of gravity that considers the boundary terms from the Einstein-Hilbert action as geometric quantum...
1805.08018
Fabio Moretti
Giovanni Montani, Fabio Moretti
Modified Gravitational Waves Across Galaxies from Macroscopic Gravity
10 pages, comments are welcome
Phys. Rev. D 100, 024045 (2019)
10.1103/PhysRevD.100.024045
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We analyze the propagation of gravitational waves in a medium containing bounded subsystems ("molecules"), able to induce significant Macroscopic Gravity effects. We establish a precise constitutive relation between the average quadrupole and the amplitudes of a vacuum gravitational wave, via the geodesic deviation e...
[ { "created": "Mon, 21 May 2018 12:34:48 GMT", "version": "v1" }, { "created": "Mon, 3 Jun 2019 09:37:36 GMT", "version": "v2" } ]
2019-07-26
[ [ "Montani", "Giovanni", "" ], [ "Moretti", "Fabio", "" ] ]
We analyze the propagation of gravitational waves in a medium containing bounded subsystems ("molecules"), able to induce significant Macroscopic Gravity effects. We establish a precise constitutive relation between the average quadrupole and the amplitudes of a vacuum gravitational wave, via the geodesic deviation equ...
gr-qc/9508022
3
Donald E. Neville
Closure of Constraints for Plane Gravity Waves
19 pages; LaTex
null
null
TU-8-95
gr-qc
null
The metric for gravitational plane waves has very high symmetry (two spacelike commuting Killing vectors). For this high symmetry, a simple renormalization of the lapse function is found which allows the constraint algebra for canonical quantum gravity to close; also, the vector constraint has the correct form to gen...
[ { "created": "Tue, 8 Aug 1995 21:00:36 GMT", "version": "v1" } ]
2007-05-23
[ [ "Neville", "Donald E.", "" ] ]
The metric for gravitational plane waves has very high symmetry (two spacelike commuting Killing vectors). For this high symmetry, a simple renormalization of the lapse function is found which allows the constraint algebra for canonical quantum gravity to close; also, the vector constraint has the correct form to gener...
1904.05363
Vitor Cardoso
Vitor Cardoso, Paolo Pani
Testing the nature of dark compact objects: a status report
76 pages + references. Invited review article for Living Reviews in Relativity. v3: Overall improvements and references added, a few typos corrected. Version to appear in LRR
Living Rev Relativ (2019) 22: 4
10.1007/s41114-019-0020-4
null
gr-qc astro-ph.HE hep-ph physics.space-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Very compact objects probe extreme gravitational fields and may be the key to understand outstanding puzzles in fundamental physics. These include the nature of dark matter, the fate of spacetime singularities, or the loss of unitarity in Hawking evaporation. The standard astrophysical description of collapsing objec...
[ { "created": "Wed, 10 Apr 2019 18:00:05 GMT", "version": "v1" }, { "created": "Tue, 16 Apr 2019 08:38:13 GMT", "version": "v2" }, { "created": "Thu, 13 Jun 2019 08:23:28 GMT", "version": "v3" } ]
2021-01-20
[ [ "Cardoso", "Vitor", "" ], [ "Pani", "Paolo", "" ] ]
Very compact objects probe extreme gravitational fields and may be the key to understand outstanding puzzles in fundamental physics. These include the nature of dark matter, the fate of spacetime singularities, or the loss of unitarity in Hawking evaporation. The standard astrophysical description of collapsing objects...
2303.06788
Eleni-Alexandra Kontou
Eleni-Alexandra Kontou and Veronica Sacchi
A generalization of the Hawking black hole area theorem
25 pages, 4 figures
null
null
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Hawking's black hole area theorem was proven using the null energy condition (NEC), a pointwise condition violated by quantum fields. The violation of the NEC is usually cited as the reason that black hole evaporation is allowed in the context of semiclassical gravity. Here we provide two generalizations of the class...
[ { "created": "Mon, 13 Mar 2023 00:24:02 GMT", "version": "v1" } ]
2023-03-14
[ [ "Kontou", "Eleni-Alexandra", "" ], [ "Sacchi", "Veronica", "" ] ]
Hawking's black hole area theorem was proven using the null energy condition (NEC), a pointwise condition violated by quantum fields. The violation of the NEC is usually cited as the reason that black hole evaporation is allowed in the context of semiclassical gravity. Here we provide two generalizations of the classic...
2107.10120
Emanuel Gallo
Emanuel Gallo, Carlos Kozameh, Thomas M\"adler, Osvaldo M. Moreschi and Alejandro P\'erez
Spherically symmetric black holes and affine-null metric formulation of Einstein's equations
17 pages
null
10.1103/PhysRevD.104.084048
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The definition of well-behaved coordinate charts for black hole spacetimes can be tricky, as they can lead for example to either unphysical coordinate singularities in the metric (e.g. $r=2M$ in the Schwarzschild black hole) or to an implicit dependence of the chosen coordinate to physical relevant coordinates (e.g. ...
[ { "created": "Wed, 21 Jul 2021 14:46:23 GMT", "version": "v1" } ]
2021-10-20
[ [ "Gallo", "Emanuel", "" ], [ "Kozameh", "Carlos", "" ], [ "Mädler", "Thomas", "" ], [ "Moreschi", "Osvaldo M.", "" ], [ "Pérez", "Alejandro", "" ] ]
The definition of well-behaved coordinate charts for black hole spacetimes can be tricky, as they can lead for example to either unphysical coordinate singularities in the metric (e.g. $r=2M$ in the Schwarzschild black hole) or to an implicit dependence of the chosen coordinate to physical relevant coordinates (e.g. th...
gr-qc/0403102
Leonardo Fernandez-Jambrina
L. Fernandez-Jambrina, F.J. Chinea
Angular Momentum Surface Density of the Kerr Metric
6 pages, LaTeX 2.09
Phys.Rev.Lett. 71 (1993) 2521-2523
10.1103/PhysRevLett.71.2521
null
gr-qc
null
A method for interpreting discontinuities of the twist potential of vacuum stationary axisymmetric solutions of Einstein's equations is introduced. Surface densities for the angular momentum of the source can be constructed after solving a linear partial differential equation with boundary conditions at infinity. Thi...
[ { "created": "Thu, 25 Mar 2004 10:25:11 GMT", "version": "v1" } ]
2009-11-10
[ [ "Fernandez-Jambrina", "L.", "" ], [ "Chinea", "F. J.", "" ] ]
A method for interpreting discontinuities of the twist potential of vacuum stationary axisymmetric solutions of Einstein's equations is introduced. Surface densities for the angular momentum of the source can be constructed after solving a linear partial differential equation with boundary conditions at infinity. This ...
0812.4944
Jiri Podolsky
Jiri Podolsky, Ondrej Prikryl
On conformally flat and type N pure radiation metrics
13 pages, typos corrected. To appear in Gen. Relativ. Gravit
Gen.Relativ.Grav.41:1069, 2009
10.1007/s10714-008-0692-7
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study pure radiation spacetimes of algebraic types O and N with a possible cosmological constant. In particular, we present explicit transformations which put these metrics, that were recently re-derived by Edgar, Vickers and Machado Ramos, into a general Ozsvath-Robinson-Rozga form. By putting all such metrics in...
[ { "created": "Mon, 29 Dec 2008 17:35:12 GMT", "version": "v1" }, { "created": "Fri, 9 Jan 2009 10:22:20 GMT", "version": "v2" } ]
2014-06-04
[ [ "Podolsky", "Jiri", "" ], [ "Prikryl", "Ondrej", "" ] ]
We study pure radiation spacetimes of algebraic types O and N with a possible cosmological constant. In particular, we present explicit transformations which put these metrics, that were recently re-derived by Edgar, Vickers and Machado Ramos, into a general Ozsvath-Robinson-Rozga form. By putting all such metrics into...
1811.02931
David McNutt
D. D. McNutt and A. A. Coley
Geometric Horizons in the Kastor-Traschen Multi Black Hole Solutions
24 pages, 17 figures
Physical Review D, 98, 064043 (2018)
10.1103/PhysRevD.98.064043
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate the existence of invariantly defined quasi-local hypersurfaces in the Kastor-Traschen solution containing $N$ charge-equal-to-mass black holes. These hypersurfaces are characterized by the vanishing of particular curvature invariants, known as Cartan invariants, which are generated using the frame appr...
[ { "created": "Wed, 7 Nov 2018 15:26:24 GMT", "version": "v1" } ]
2018-11-08
[ [ "McNutt", "D. D.", "" ], [ "Coley", "A. A.", "" ] ]
We investigate the existence of invariantly defined quasi-local hypersurfaces in the Kastor-Traschen solution containing $N$ charge-equal-to-mass black holes. These hypersurfaces are characterized by the vanishing of particular curvature invariants, known as Cartan invariants, which are generated using the frame approa...
1603.00712
Roberto Emparan
Roberto Emparan, Marina Martinez
Exact Event Horizon of a Black Hole Merger
21 pages, 17 figures. v2: Improved perturbative and critical analysis. Ancillary 3D animation of the merger. 24 pages, 18 figures. v3: minor improvements. 25 pages, 18 figures
Class.Quant.Grav. 33 (2016) 15, 155003
10.1088/0264-9381/33/15/155003
null
gr-qc hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We argue that the event horizon of a binary black hole merger, in the extreme-mass-ratio limit where one of the black holes is much smaller than the other, can be described in an exact analytic way. This is done by tracing in the Schwarzschild geometry a congruence of null geodesics that approaches a null plane at in...
[ { "created": "Wed, 2 Mar 2016 13:52:22 GMT", "version": "v1" }, { "created": "Thu, 17 Mar 2016 15:03:40 GMT", "version": "v2" }, { "created": "Mon, 27 Jun 2016 18:16:46 GMT", "version": "v3" } ]
2022-03-07
[ [ "Emparan", "Roberto", "" ], [ "Martinez", "Marina", "" ] ]
We argue that the event horizon of a binary black hole merger, in the extreme-mass-ratio limit where one of the black holes is much smaller than the other, can be described in an exact analytic way. This is done by tracing in the Schwarzschild geometry a congruence of null geodesics that approaches a null plane at infi...
1604.00899
Subhajit Saha
Subhajit Saha and Anindita Mondal
Thermodynamic implications of the gravitationally induced particle creation scenario
7 pages, 1 figure, 1 table; v2: Minor changes in format and style; v3: Typos corrected, Identical to published version
The European Physical Journal C 77, 196 (2017); Erratum: The European Physical Journal C 78, 295 (2018)
10.1140/epjc/s10052-017-4746-4
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A rigorous thermodynamic analysis has been done at the apparent horizon of a spatially flat Friedmann-Lemaitre-Robertson-Walker universe for the gravitationally induced particle creation scenario with constant specific entropy and an arbitrary particle creation rate $\Gamma$. Assuming a perfect fluid equation of stat...
[ { "created": "Fri, 1 Apr 2016 06:49:29 GMT", "version": "v1" }, { "created": "Tue, 13 Dec 2016 09:08:20 GMT", "version": "v2" }, { "created": "Thu, 30 Mar 2017 10:27:29 GMT", "version": "v3" } ]
2019-10-24
[ [ "Saha", "Subhajit", "" ], [ "Mondal", "Anindita", "" ] ]
A rigorous thermodynamic analysis has been done at the apparent horizon of a spatially flat Friedmann-Lemaitre-Robertson-Walker universe for the gravitationally induced particle creation scenario with constant specific entropy and an arbitrary particle creation rate $\Gamma$. Assuming a perfect fluid equation of state ...
gr-qc/9602019
Donald Marolf
Donald Marolf
Path Integrals and Instantons in Quantum Gravity
23 pages, ReVTeX, minor changes: clarifying Comments and references added
Phys.Rev.D53:6979-6990,1996
10.1103/PhysRevD.53.6979
UCSBTH-96-01
gr-qc hep-th
null
While there does not at this time exist a complete canonical theory of full 3+1 quantum gravity, there does appear to be a satisfactory canonical quantization of minisuperspace models. The method requires no `choice of time variable' and preserves the systems' explicit reparametrization invariance. In the following s...
[ { "created": "Mon, 12 Feb 1996 01:02:32 GMT", "version": "v1" }, { "created": "Sun, 18 Feb 1996 01:06:40 GMT", "version": "v2" } ]
2011-09-09
[ [ "Marolf", "Donald", "" ] ]
While there does not at this time exist a complete canonical theory of full 3+1 quantum gravity, there does appear to be a satisfactory canonical quantization of minisuperspace models. The method requires no `choice of time variable' and preserves the systems' explicit reparametrization invariance. In the following stu...
2203.14599
Alexey Toporensky
N. Avdeev and A. Toporensky
Ruling out an inflation driven by a power law potential: kinetic coupling does not help
4 pages with 1 eps figure; title and abstract have been changed to better match with the result obtained; to appear in Gravitation and Cosmology
null
10.1134/S0202289322040028
null
gr-qc
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We demonstrate that the latest constraints on inflationary observables, namely the tensor-to-scalar ratio $r$ and the scalar spectral index $n_{_S}$, from the Cosmic Background Radiation (CMB) observations are already strong enough to rule out the model of a scalar field with a power law potential even in the presenc...
[ { "created": "Mon, 28 Mar 2022 09:19:59 GMT", "version": "v1" }, { "created": "Thu, 31 Mar 2022 15:52:45 GMT", "version": "v2" }, { "created": "Sat, 15 Oct 2022 07:51:20 GMT", "version": "v3" } ]
2022-12-07
[ [ "Avdeev", "N.", "" ], [ "Toporensky", "A.", "" ] ]
We demonstrate that the latest constraints on inflationary observables, namely the tensor-to-scalar ratio $r$ and the scalar spectral index $n_{_S}$, from the Cosmic Background Radiation (CMB) observations are already strong enough to rule out the model of a scalar field with a power law potential even in the presence ...