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In this paper, we consider the bulk plus boundary phase space for three-dimensional gravity with negative cosmological constant for a particular choice of conformal boundary conditions: the conformal class of the induced metric at the…

General Relativity and Quantum Cosmology · Physics 2020-04-22 Jeevan Chandra Namburi , Wolfgang Wieland

Current and coming surveys will require sub-percent agreement in theoretical accuracy to test the different cosmological and gravity scenarios. This can be performed with Boltzmann solvers, i.e. codes that solve the linear evolution of…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-13 Rubén Arjona

This study focuses on the impact of the cosmological constant on hyperbolically symmetric matter configurations in static background. We extend the work of Herrera \cite{herrera2021hyperbolically} and describe the influences of such…

General Relativity and Quantum Cosmology · Physics 2024-10-03 Z. Yousaf

We review the effective field theory of modified gravity in which the Lagrangian involves three dimensional geometric quantities appearing in the 3+1 decomposition of space-time. On the flat isotropic cosmological background we expand a…

High Energy Physics - Theory · Physics 2015-02-24 Ryotaro Kase , Shinji Tsujikawa

In this work, we derive a new class of analytic black hole solutions within the framework of f(R,Lm, T) gravity, where the black hole is surrounded by an anisotropic fluid acting as the matter source. We consider both linear and nonlinear…

General Relativity and Quantum Cosmology · Physics 2025-06-19 Aniruddha Ghosh , Ujjal Debnath

Recently, the static spherically symmetric solution of the gravitational field equations have been found in theories describing massive graviton with spontaneous breaking of the Lorentz invariance. These solutions, which show off two…

General Relativity and Quantum Cosmology · Physics 2009-05-07 Michael V. Bebronne

The cosmological application of a dark viscous fluid in a spatially flat Friedmann-Robertson-Walker (FRW) universe with a modified logarithmic equation of state (EoS), being an analogue of the equation associated with the isotropic…

General Relativity and Quantum Cosmology · Physics 2026-04-02 I. Brevik , A. V. Timoshkin

We study holographic entanglement entropy in the background of charged dilatonic black holes which can be viewed as holographic duals of certain finite density states of N=4 super Yang-Mills. These charged black holes are distinguished in…

High Energy Physics - Theory · Physics 2012-10-22 Manuela Kulaxizi , Andrei Parnachev , Koenraad Schalm

To ask a question about a black hole in quantum gravity, one must restrict initial or boundary data to ensure that a black hole is actually present. For two-dimensional dilaton gravity, and probably a much wider class of theories, I show…

High Energy Physics - Theory · Physics 2010-04-28 S. Carlip

The present article is the last in a series of five devoted to the study of the effect of anisotropic pressure on the gravitationnal impact of a stationary rigidly rotating cylindrically symmetric fluid with the use of new exact solutions…

General Relativity and Quantum Cosmology · Physics 2023-05-24 Marie-No\''elle Célérier

The version of the cosmological perturbation theory based on exact resolution of energy constraint is developed in accordance with the diffeomorphisms of general relativity in the Dirac Hamiltonian approach. Such exact resolution gives one…

Astrophysics · Physics 2009-11-13 B. M. Barbashov , V. N. Pervushin , A. F. Zakharov , V. A. Zinchuk

As a candidate of quantum gravity in ultrahigh energy, the $(3+1)$-dimensional Ho\v{r}ava-Lifshitz (HL) gravity with critical exponent $z\ne 1$, indicates anisotropy between time and space at short distance. In the paper, we investigate the…

High Energy Physics - Theory · Physics 2015-12-15 Tian-Jun Li , Yong-Hui Qi , Yue-Liang Wu , Yun-Long Zhang

In order to explore some general features of modified theories of gravity which involve higher derivatives and spontaneous Lorentz and/or diffeomorphism symmetry breaking, we study the recently proposed new version of covariant…

General Relativity and Quantum Cosmology · Physics 2013-04-16 Masud Chaichian , Josef Klusoň , Markku Oksanen , Anca Tureanu

Galactic dark matter is modelled by a scalar field in order to effectively modify Kepler's law without changing standard Newtonian gravity. In particular, a solvable toy model with a self-interaction U(Phi) borrowed from non-topological…

Astrophysics · Physics 2016-11-09 Eckehard W. Mielke , Burkhard Fuchs , Franz E. Schunck

A argument is described for how deformed or doubly special relativity may arise in the semiclassical limit of a quantum theory of gravity. We consider a generic quantum theory of gravity coupled to matter, from which we use only the…

High Energy Physics - Theory · Physics 2008-08-28 Lee Smolin

In our investigation, we pioneer the development of geometrically deformed strange stars within the framework of teleparallel gravity theory through gravitational decoupling via the complete geometric deformation (CGD) technique. The…

General Relativity and Quantum Cosmology · Physics 2025-02-05 Sneha Pradhan , Piyali Bhar , Sanjay Mandal , P. K. Sahoo , Kazuharu Bamba

Anisotropic dark energy model with dynamic pressure anisotropies along different spatial directions is constructed at the backdrop of a spatially homogeneous diagonal Bianchi type $V$ $(BV)$ space-time in the framework of General…

General Physics · Physics 2017-05-10 B. Mishra , S. K. Tripathy

Extensions of Einstein's General Relativity (GR) can formally be given a GR structure in which additional geometric degrees of freedom are mapped on an effective energy-momentum tensor. The corresponding effective cosmic medium can then be…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-11 Winfried Zimdahl , Hermano Velten , William C. Algoner

We describe how a certain simple modification of general relativity, in which the local cosmological constant is allowed to depend on the space-time curvature, predicts the existence of halos of modified gravity surrounding…

General Relativity and Quantum Cosmology · Physics 2009-03-20 Kirill Krasnov , Yuri Shtanov

Two dimensional (2D) analogue of vacuum sector of the Brans Dicke (BD) gravity [1] is studied to obtain dynamics of anisotropic spherically symmetric perfect fluid. Our obtained static solutions behave as dark matter with state equation…

General Relativity and Quantum Cosmology · Physics 2017-06-29 Hossein Ghaffarnejad