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相关论文: Quantum gravitational Kasner transitions in Bianch…

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Singularities in general relativity such as the big bang and big crunch, and exotic singularities such as the big rip are the boundaries of the classical spacetimes. These events are marked by a divergence in the curvature invariants and…

广义相对论与量子宇宙学 · 物理学 2015-10-01 Parampreet Singh

We study anisotropic Bianchi-I cosmology, incorporating quantum gravitational corrections into the Einstein equation through the scale-dependent Newton coupling and cosmological term, as determined by the flow equation of the effective…

广义相对论与量子宇宙学 · 物理学 2025-12-03 Chiang-Mei Chen , Akihiro Ishibashi , Rituparna Mandal , Nobuyoshi Ohta

We study quantum corrections to the classical Bianchi I and Bianchi IX universes. The modified dynamics is well-motivated from the asymptotic safety program where the short-distance behavior of gravity is governed by a non-trivial…

广义相对论与量子宇宙学 · 物理学 2016-01-06 Giulio D'Odorico , Frank Saueressig

We discuss the question of time in a Bianchi I quantum cosmology in the framework of singularity avoidance. We show that time parameters fall into two distinct classes, that are such that the time development of the wave function either…

广义相对论与量子宇宙学 · 物理学 2020-02-18 Przemyslaw Malkiewicz , Patrick Peter , S. D. P. Vitenti

We numerically investigate the solutions to the effective equations of the Bianchi II model within the "improved" Loop Quantum Cosmology (LQC) dynamics. The matter source is a massless scalar field. We perform a systematic study of the…

广义相对论与量子宇宙学 · 物理学 2012-10-08 Alejandro Corichi , Edison Montoya

Several examples are known where quantum gravity effects resolve the classical big bang singularity by a bounce. The most detailed analysis has probably occurred for loop quantum cosmology of isotropic models sourced by a free, massless…

广义相对论与量子宇宙学 · 物理学 2008-12-18 Martin Bojowald

We analyze the Bianchi I cosmology in the presence of a massless scalar field and describe its dynamics via a semiclassical and quantum polymer approach. We study the morphology of the Big Bounce by adopting three different sets of…

广义相对论与量子宇宙学 · 物理学 2022-03-09 E. Giovannetti , G. Montani , S. Schiattarella

We study the effects of a spatially homogenous magnetic field in Bianchi-I cosmological models. The cases of a pure magnetic field and two models with additional dust and a massless scalar field (stiff matter) are also considered. At the…

广义相对论与量子宇宙学 · 物理学 2023-10-31 Roberto Casadio , Alexander Kamenshchik , Panagiotis Mavrogiannis , Polina Petriakova

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

We investigate the evolution of a homogeneous magnetic field within Bianchi-I loop quantum cosmology, in which the big bang singularity is replaced with an anisotropic quantum bounce. Using effective spacetime description, we conduct…

广义相对论与量子宇宙学 · 物理学 2024-06-18 Meysam Motaharfar , Parampreet Singh

The approach of a quantum state to a cosmological singularity is studied through the evolution of its moments in a simple version of a Bianchi I model. In spite of the simplicity, the model exhibits several instructive and unexpected…

广义相对论与量子宇宙学 · 物理学 2020-06-03 Ana Alonso-Serrano , Martin Bojowald , David Brizuela

We investigate the classical and quantum behavior of a Bianchi I model in the presence of a stiff matter contribution when the Vilenkin interpretation of the wave function of the Universe is taken into account. We study its evolution in the…

广义相对论与量子宇宙学 · 物理学 2017-08-02 Riccardo Moriconi , Giovanni Montani

The loop quantum cosmology "improved dynamics" of the Bianchi type IX model are studied. The action of the Hamiltonian constraint operator is obtained via techniques developed for the Bianchi type I and type II models, no new input is…

广义相对论与量子宇宙学 · 物理学 2014-11-21 Edward Wilson-Ewing

The detailed formulation for loop quantum cosmology (LQC) in the Bianchi I model with a massless scalar field was recently constructed. In this paper, its effective dynamics with the LQC discreteness corrections is studied and the equations…

广义相对论与量子宇宙学 · 物理学 2007-09-12 Dah-Wei Chiou

After a brief introduction, basic ideas of the quantum Riemannian geometry underlying loop quantum gravity are summarized. To illustrate physical ramifications of quantum geometry, the framework is then applied to homogeneous isotropic…

广义相对论与量子宇宙学 · 物理学 2009-11-11 Abhay Ashtekar

Quantum effects are expected to modify the cosmological dynamics of the early universe while maintaining some (potentially discrete) notion of space-time structure. In one approach, loop quantum cosmology, current models are shown here to…

广义相对论与量子宇宙学 · 物理学 2026-04-29 Martin Bojowald , Manuel Diaz , Erick I. Duque

The cosmological singularities of the Bianchi I universe are analyzed in the setting of loop geometry underlying the loop quantum cosmology. We solve the Hamiltonian constraint of the theory and find the Lie algebra of elementary…

广义相对论与量子宇宙学 · 物理学 2014-11-20 Piotr Dzierzak , Wlodzimierz Piechocki

We describe the quantum evolution of the vacuum Bianchi II universe in terms of the transition amplitude between two asymptotic quantum Kasner-like states. For large values of the momentum variable the classical and quantum calculations…

广义相对论与量子宇宙学 · 物理学 2015-06-19 Hervé Bergeron , Orest Hrycyna , Przemysław Małkiewicz , Włodzimierz Piechocki

In this manuscript, we investigate the oscillatory behaviour of the anisotropy in the diagonal Bianchi-I spacetimes. Our starting point is a simplification of Einstein's equations using only observable or physical variables. As a…

广义相对论与量子宇宙学 · 物理学 2021-04-02 Leandro G Gomes , Bruno B. Bizarria , Gabriel A. de Souza Silva , William O. Clavijo

In loop quantum cosmology, ambiguities in the Hamiltonian constraint can result in models with varying phenomenological predictions. In the homogeneous isotropic models, these ambiguities were settled, and the improved dynamics was found to…

广义相对论与量子宇宙学 · 物理学 2023-11-16 Meysam Motaharfar , Parampreet Singh , Eklavya Thareja