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相关论文: Bouncing Bianchi Models with Deformed Commutation …

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The dynamics of cosmological anisotropies is investigated for Bianchi type I universe filled by a relativistic matter represented by the reduced relativistic gas model (RRG), with equation of state interpolating between radiation and…

广义相对论与量子宇宙学 · 物理学 2019-08-20 Simpliciano Castardelli dos Reis , Ilya L. Shapiro

We consider the dynamics of a barotropic cosmological fluid in an anisotropic, Bianchi type I space-time in Eddington-inspired Born-Infeld (EiBI) gravity. By assuming an isotropic pressure distribution, we obtain the general solution of the…

广义相对论与量子宇宙学 · 物理学 2014-10-30 Tiberiu Harko , Francisco S. N. Lobo , M. K. Mak

In this work we construct an effective four-dimensional model by compactifying a ten-dimensional theory of gravity coupled with a real scalar dilaton field on a time-dependent torus. This approach is applied to anisotropic cosmological…

广义相对论与量子宇宙学 · 物理学 2016-05-18 L. Toledo Sesma , J. Socorro , O. Loaiza

In arXiv:2603.18175, the authors argue, based on numerical studies of particular cases, that the quantum damping of cosmological shear in a modified loop quantum cosmological model (mLQC-I) that was recently found in arXiv:2510.14021 is not…

广义相对论与量子宇宙学 · 物理学 2026-04-13 Wen-Cong Gan , Leila L. Graef , Rudnei O. Ramos , Gustavo S. Vicente , Anzhong Wang

In this paper we present the noncommutative Bianchi Class A cosmological models coupled to barotropic perfect fluid. The commutative and noncommutative quantum solution to the Wheeler-DeWitt equation for any factor ordering, to the…

广义相对论与量子宇宙学 · 物理学 2008-11-26 M. Aguero , J. A. Aguilar S. , C. Ortiz , M. Sabido , J. Socorro

The primary aim of this work is to explore feasible bouncing cosmological solutions in the framework of $f(\mathcal{Q}, \mathcal{C})$ gravity, where $\mathcal{Q}$ denotes non-metricity and $\mathcal{C}$ indicates the boundary term. To…

广义相对论与量子宇宙学 · 物理学 2025-08-12 M. Sharif , M. Zeeshan Gul , Ahmad Nawaz

Contrary to the general belief, there has recently been quite a few examples of unitary evolution of quantum cosmological models. The present work gives more examples, namely Bianchi type VI and type II. These examples are important as they…

广义相对论与量子宇宙学 · 物理学 2016-11-03 Sachin Pandey , Narayan Banerjee

In this article, we present a generic dynamical system formulation for Bianchi-I cosmology in the presence of an isotropic fluid within the coincident gauge connection branch and one of the non-coincident gauge connection branches of $f(Q)$…

广义相对论与量子宇宙学 · 物理学 2025-09-03 Ghulam Murtaza , Saikat Chakraborty , Avik De

The implications of a deformed Heisenberg algebra on the Friedmann-Robertson-Walker cosmological models are investigated. We consider the Snyder non-commutative space in which the translation group is undeformed and the rotational…

广义相对论与量子宇宙学 · 物理学 2009-04-10 Marco Valerio Battisti

In this paper we analyse the Bianchi IX Universe dynamics within the corner region associated to the potential term which the spatial curvature induces in the Minisuperspace. The study is done in the vacuum and in the presence of a massless…

广义相对论与量子宇宙学 · 物理学 2020-10-21 Roberta Chiovoloni , Giovanni Montani , Valerio Cascioli

There are evidences that the cosmic microwave background (CMB) large-angle anomalies imply a departure from statistical isotropy and hence from the standard cosmological model. We propose a LCDM model extension whose dark energy component…

天体物理学 · 物理学 2008-11-26 Davi C. Rodrigues

We examine the dynamical consequences of homogeneous cosmological magnetic fields in the framework of loop quantum cosmology. We show that a big-bounce occurs in a collapsing magnetized Bianchi I universe, thus extending the known cases of…

广义相对论与量子宇宙学 · 物理学 2008-12-11 Roy Maartens , Kevin Vandersloot

We use the requirement of diffeomorphism invariance in the Bianchi I context to derive the form of the quantum Hamiltonian constraint. After imposing the correct classical behavior and making a certain minimality assumption, together with a…

广义相对论与量子宇宙学 · 物理学 2018-07-11 Jonathan Engle , Ilya Vilensky

A spatially homogeneous and locally rotationally symmetric Bianchi type-II cosmological model under the influence of both shear and bulk viscosity has been studied. Exact solutions are obtained with a barotropic equation of state between…

广义相对论与量子宇宙学 · 物理学 2021-05-11 A. Banerjee , S. B. Duttachoudhury , Abhik Kumar Sanyal

A perturbative expansion of Loop Quantum Cosmological transitions amplitudes of Bianchi I models is performed. Following the procedure outlined in [1,2] for isotropic models, it is shown that the resulting expansion can be written in the…

广义相对论与量子宇宙学 · 物理学 2010-11-12 Miguel Campiglia , Adam Henderson , William Nelson

The Bianchi IX cosmological model (through Bianchi I and II) is analyzed in the framework of a generalized uncertainty principle. In particular, the anisotropies of the Universe are described by a deformed Heisenberg algebra. Three main…

广义相对论与量子宇宙学 · 物理学 2009-03-04 Marco Valerio Battisti , Giovanni Montani

We study the dynamical evolution of an $f(R)$ model of gravity in a viscous and anisotropic background which is given by a Bianchi type-I model of the Universe. We find viable forms of $f(R)$ gravity in which one is exactly the Einsteinian…

综合物理 · 物理学 2014-01-20 Kh. Saaidi , A. Aghamohammadi , H. Hossienkhani

The present study reexamines the recent work of Pradhan et al. (Indian J. Phys. 88: 757, 2014) and obtained general exact solutions of the Einstein's field equations with variable gravitational and cosmological "constants" for a spatially…

综合物理 · 物理学 2015-08-06 Anirudh Pradhan , Bijan Saha , Victor Rikhvitsky

A generally anisotropic equation of state originally derived in the context of Newman-Janis rotating systems allows for vacuum energy at a specific density. In this paper we examine the possibility of using that equation of state for…

广义相对论与量子宇宙学 · 物理学 2023-09-08 Philip Beltracchi

We study the notion of volume and its dynamics in the loop-quantum-gravity truncation known as the two-vertex model. We also show that its U(N)-symmetry reduction provides the old effective dynamics of loop quantum cosmology with an…

广义相对论与量子宇宙学 · 物理学 2024-06-17 Álvaro Cendal , Iñaki Garay , Luis J. Garay