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We investigate the occurrence of various exotic spacelike singularities in the past and the future evolution of $k = \pm 1$ Friedmann-Robertson-Walker model and loop quantum cosmology using a sufficiently general phenomenological model for…

General Relativity and Quantum Cosmology · Physics 2015-03-17 Parampreet Singh , Francesca Vidotto

The rich phenomenology of collective neutrino oscillations has been studied only in one-dimensional or spherically symmetric systems. Motivated by the non-spherical example of coalescing neutron stars, presumably the central engines of…

High Energy Physics - Phenomenology · Physics 2008-11-26 Basudeb Dasgupta , Amol Dighe , Alessandro Mirizzi , Georg G. Raffelt

We consider here the dynamics of some homogeneous and isotropic cosmological models with $N$ interacting classical scalar fields non-minimally coupled to the spacetime curvature, as an attempt to generalize some recent results obtained for…

General Relativity and Quantum Cosmology · Physics 2007-05-23 L. Brenig , A. Figueiredo , E. Gunzig , T. M. Rocha Filho , Alberto Saa

Previous studies \cite{berger98a} have provided strong support for a local, oscillatory approach to the singularity in U(1) symmetric, spatially inhomogeneous vacuum cosmologies on $T^3 \times R$. The description of a vacuum Bianchi type…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Beverly K. Berger , Vincent Moncrief

A companion paper provides a proposal for cosmic singularity resolution based upon general features of a bouncing unitary cosmological model in the mini-superspace approximation. This paper analyses novel phenomenology that can be…

General Relativity and Quantum Cosmology · Physics 2018-12-17 Sean Gryb , Karim P. Y. Thébault

We construct a formal asymptotic series expansion for a general solution of the Brans-Dicke equations with a fluid source near a sudden singularity. This solution contains eleven independent arbitrary functions of the spatial coordinates as…

General Relativity and Quantum Cosmology · Physics 2021-02-03 John D. Barrow , Spiros Cotsakis , Dimitrios Trachilis

We investigate Bianchi I cosmological model in the theory of a dilatonM field coupled to gravity through a Gauss-Bonnet term. Two type ofM cosmological singularity are distinguished. The former is analogous toM the Einstein gravity…

General Relativity and Quantum Cosmology · Physics 2009-10-31 S. Alexeyev , A. Toporensky , V. Ustiansky

Self-consistent solutions to the spinor, scalar and BI gravitational field equations are obtained. The problems of initial singularity and asymptotically isotropization process of the initially anisotropic space-time are studied. It is also…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Bijan Saha

We study the dynamical effects in the scale factors due to the scalar $\phi$-field at the early stages of a supposedly anisotropic Universe expansion in connection with the problem of the initial singularity in the scalar-tensor cosmology…

General Relativity and Quantum Cosmology · Physics 2007-05-23 H. N. Núñez-Yépez

In this paper we present a new approach for studying the dynamics of spatially inhomogeneous cosmological models with one spatial degree of freedom. By introducing suitable scale-invariant dependent variables we write the evolution…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Henk van Elst , Claes Uggla , John Wainwright

The full spectrum and integrability of unitary equivalent models are the same. A standard diagnostic tool of integrability is level spacing statistics which requires separating the full spectrum into sectors according to the symmetry. When…

Statistical Mechanics · Physics 2025-04-29 Biquan Yang , Zijian Xiong

The modelling of light-like signals in General Relativity taking the form of impulsive gravitational waves and light-like shells of matter is examined. Systematic deductions from the Bianchi identities are made. These are based upon…

General Relativity and Quantum Cosmology · Physics 2009-10-31 C. Barrabès , P. A. Hogan

We study the Tolman-Oppenheimer-Volkoff equation in the presence of a cosmological constant for general thermodynamically consistent equations of state, without imposing regularity at the center. Formulating the problem as an initial value…

General Relativity and Quantum Cosmology · Physics 2026-04-16 Christos Dounis , Charis Anastopoulos

We provide a quantum picture for the emergence of a bouncing cosmology, according to the idea that a semiclassical behavior of the Universe towards the singularity is not available in many relevant Minisuperspace models. In particular, we…

General Relativity and Quantum Cosmology · Physics 2022-09-07 Eleonora Giovannetti , Giovanni Montani

In this work we analyse asymptotically flat, spherically symmetric spacetimes in which an event horizon is present without any trapped surfaces. We identify two types of such spacetimes, each related to the asymptotic behaviour (in time) of…

General Relativity and Quantum Cosmology · Physics 2020-12-07 Carlos Barceló , Valentin Boyanov , Raúl Carballo-Rubio , Luis J. Garay

We prove sharp blow up rates of solutions of higher order conformally invariant equations in a bounded domain with an isolated singularity, and show the asymptotic radial symmetry of the solutions near the singularity. This is an extension…

Analysis of PDEs · Mathematics 2019-01-15 Tianling Jin , Jingang Xiong

We investigate the conditions under which cosmological variations in physical `constants' and scalar fields are detectable on the surface of local gravitationally-bound systems, such as planets, in non-spherically symmetric background…

General Relativity and Quantum Cosmology · Physics 2011-07-19 Douglas J. Shaw , John D. Barrow

Black hole solutions in general relativity are simple. The frequency spectrum of linear perturbations around these solutions (i.e., the quasinormal modes) is also simple, and therefore it is a prime target for fundamental tests of black…

General Relativity and Quantum Cosmology · Physics 2024-02-09 Vitor Cardoso , Masashi Kimura , Andrea Maselli , Emanuele Berti , Caio F. B. Macedo , Ryan McManus

The Born-Infeld determinantal gravity has been recently proposed as a way to smooth the Big Bang singularity. This theory is formulated on the Weitzenbock space-time and the teleparallel representation is used instead of the standard…

General Relativity and Quantum Cosmology · Physics 2014-12-24 Mariam Bouhmadi-Lopez , Che-Yu Chen , Pisin Chen

(Shortened abstract) While a featureless, nearly scale invariant, primordial scalar power spectrum fits the most recent CMB data rather well, certain features in the spectrum are known to lead to a better fit to the data (although, the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Jerome Martin , L. Sriramkumar
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