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We obtain a scaling relation for spherically symmetric k-essence scalar fields $\phi(r,t)$ for an inhomogeneous cosmology with the Lemaitre-Tolman- Bondi (LTB) metric. We show that this scaling relation reduces to the known relation for a…

General Relativity and Quantum Cosmology · Physics 2021-08-21 Somnath Mukherjee , Debashis Gangopadhyay

We obtain a scaling relation for spherically symmetric k-essence scalar fields $\phi(r,t)$ for an inhomogeneous cosmology with the Lemaitre-Tolman- Bondi (LTB) metric. We show that this scaling relation reduces to the known relation for a…

General Relativity and Quantum Cosmology · Physics 2021-03-12 Debashis Gangopadhyay , Somnath Mukherjee

We derive a class of non-static inhomogeneous dust solutions in f(R) gravity described by the Lemaitre-Tolman-Bondi (LTB) metric. The field equations are fully integrated for all parameter subcases and compared with analogous subcases of…

General Relativity and Quantum Cosmology · Physics 2017-11-28 Roberto A Sussman , Luisa G Jaime

I discuss the spherically symmetric but inhomogeneous Lemaitre-Tolman- Bondi (LTB) metric, which provides an exact toy model for an inhomogeneous universe. Since we observe light rays from the past light cone, not the expansion of the…

Astrophysics · Physics 2008-11-26 Kari Enqvist

We examine a large class of inhomogeneous spherically symmetric spacetimes that generalize the Lemaitre-Tolman-Bondi dust solutions to nonzero pressure ("LTB spacetimes"). Local covariant LTB objects can be expressed as perturbations of…

General Relativity and Quantum Cosmology · Physics 2010-05-12 Roberto A. Sussman

Many recent researches have investigated the deviations from the Friedmannian cosmological model, as well as their consequences on unexplained cosmological phenomena, such as dark matter and the acceleration of the Universe. On the one…

General Relativity and Quantum Cosmology · Physics 2021-09-22 Sergio Cacciatori , Alessio Marrani , Federico Re

In this paper we explore the possibility to find exact solutions for Teleparallel Gravity (TG) of the type of spherically symmetric Lema\^\i tre-Tolman-Bondi (LTB) dust models. We apply to the LTB metric the formalism of Teleparallel…

General Relativity and Quantum Cosmology · Physics 2022-03-28 Sebastián Nájera , Aram Aguilar , Geovanny A. Rave-Franco , Celia Escamilla-Rivera , Roberto A. Sussman

As an alternative to dark energy that explains the observed acceleration of the universe, it has been suggested that we may be at the center of an inhomogeneous isotropic universe described by a Lemaitre-Tolman-Bondi (LTB) solution of…

Cosmology and Nongalactic Astrophysics · Physics 2011-11-04 Antonio Enea Romano , Misao Sasaki

A numerical approach is considered for spherically symmetric spacetimes that generalize Lemaitre-Tolman-Bondi dust solutions to nonzero pressure ("LTB spacetimes"). We introduce quasi-local (QL) variables that are covariant LTB objects…

General Relativity and Quantum Cosmology · Physics 2010-05-12 Roberto A. Sussman

We perform numerical simulations of large scale structure evolution in an inhomogeneous Lemaitre-Tolman-Bondi (LTB) model of the Universe. We follow the gravitational collapse of a large underdense region (a void) in an otherwise flat…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 David Alonso , Juan Garcia-Bellido , Troels Haugboelle , Julian Vicente

We, first, analytically work out the long-term, i.e. averaged over one orbital revolution, perturbations on the orbit of a test particle moving in a local Fermi frame induced therein by the cosmological tidal effects of the inhomogeneous…

General Relativity and Quantum Cosmology · Physics 2010-06-07 Lorenzo Iorio

We revisited the problem of describing, on average, a fractal distribution of matter using a Lemaitre-Tolman-Bondi (LTB) solution. Here we study the fractal structure of our local universe having a fractal dimension and a scale transition,…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-05 Erick Pastén , Víctor H. Cárdenas

We examine in this paper the possibility of finding exact solutions for Teleparallel Gravity (TG) of the type of spherically symmetric Lema\^\i tre-Tolman-Bondi (LTB) dust models. We apply to the LTB metric, as obtained from the…

General Relativity and Quantum Cosmology · Physics 2021-06-07 Sebastián Nájera , Aram Aguilar , Celia Escamilla-Rivera , Roberto A. Sussman

In this paper we attempt to answer to the question: can cosmic acceleration of the Universe have a fractal solution? We give an exact solution of a Lema\^itre-Tolman-Bondi (LTB) Universe based on the assumption that such a smooth metric is…

Cosmology and Nongalactic Astrophysics · Physics 2019-01-30 Leonardo Cosmai , Giuseppe Fanizza , Francesco Sylos Labini , Luciano Pietronero , Luigi Tedesco

We present a new model universe based on the junction of FRW to flat Lemaitre-Tolman-Bondi (LTB) solutions of Einstein equations along our past light cone, bringing structures within the FRW models. The model is assumed globally to be…

Astrophysics · Physics 2008-11-26 Sh. Khosravi , E. Kourkchi , R. Mansouri , Y. Akrami

We introduce a quasi-local integral functional and scalar quasi-local variables to examine a wide class of spherically symmetric inhomogeneous spacetimes that generalize the Lemaitre-Tolman-Bondi (LTB) dust solutions ("LTB" spacetimes). By…

General Relativity and Quantum Cosmology · Physics 2008-09-22 Roberto A Sussman

Lemaitre-Tolman-Bondi models as specific spherically symmetric solutions of general relativity simplify in their reduced form some of the mathematical ingredients of black hole or cosmological applications. The conditions imposed in…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Martin Bojowald , Tomohiro Harada , Rakesh Tibrewala

Lema\^{i}tre-Tolman-Bondi (LTB) solutions have traditionally been confined to systems with no pressure in which the gravity is due to massive dust, but the solutions are little changed in form if, as in cosmology, the pressure is uniform in…

General Relativity and Quantum Cosmology · Physics 2016-03-07 Donald Lynden-Bell , Jiří Bičák

We analyze inhomogeneous cosmological models in the local Universe, described by the Lema\^itre-Tolman-Bondi (LTB) metric and developed using linear perturbation theory on a homogeneous and isotropic Universe background. Focusing on the…

General Relativity and Quantum Cosmology · Physics 2024-05-16 Tiziano Schiavone , Giovanni Montani

The inverse problem with Lema\^itre-Tolman-Bondi (LTB) universe models is discussed. The LTB solution for the Einstein equations describes the spherically symmetric dust-filled spacetime. The LTB solution has two physical functional degrees…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Chul-Moon Yoo
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