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We derive transition rules for Kasner exponents in bouncing Bianchi I models with generic perfect fluid matter fields for a broad class of modified gravity theories where cosmological singularities are resolved and replaced by a…

General Relativity and Quantum Cosmology · Physics 2019-12-12 Marco de Cesare , Edward Wilson-Ewing

A new model is studied which describes the quantum behavior of transitions through an isotropic quantum cosmological bounce in loop quantum cosmology sourced by a free and massless scalar field. As an exactly solvable model even at the…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Martin Bojowald

A brief review of various numerical techniques used in loop quantum cosmology and results is presented. These include the way extensive numerical simulations shed insights on the resolution of classical singularities, resulting in the key…

General Relativity and Quantum Cosmology · Physics 2013-07-11 Parampreet Singh

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 investigate the morphology of the emerging Big Bounce by adopting three different…

General Relativity and Quantum Cosmology · Physics 2022-03-10 Eleonora Giovannetti , Giovanni Montani , Silvia Schiattarella

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…

General Relativity and Quantum Cosmology · Physics 2008-12-11 Roy Maartens , Kevin Vandersloot

We present the method of describing an evolution in quantum cosmology in the framework of the reduced phase space quantization of loop cosmology. We apply our method to the flat Friedman-Robertson-Walker model coupled to a massless scalar…

General Relativity and Quantum Cosmology · Physics 2012-03-06 Jakub Mielczarek , Wlodzimierz Piechocki

In this contribution we consider the issue of singularity resolution within loop quantum cosmology (LQC) for different homogeneous models. We present results of numerical evolutions of effective equations for both isotropic as well as…

General Relativity and Quantum Cosmology · Physics 2012-12-04 Alejandro Corichi , Asieh Karami , Edison Montoya

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…

General Relativity and Quantum Cosmology · Physics 2014-11-20 Piotr Dzierzak , Wlodzimierz Piechocki

We present a dynamical analysis in terms of new expansion-normalized variables for homogeneous and anisotropic Bianchi-I spacetimes in $f(R)$ gravity in the presence of anisotropic matter. With a suitable choice of the evolution parameter,…

General Relativity and Quantum Cosmology · Physics 2019-03-29 Saikat Chakraborty , Kazuharu Bamba , Alberto Saa

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…

General Relativity and Quantum Cosmology · Physics 2018-07-11 Jonathan Engle , Ilya Vilensky

We examine the anisotropy originated from a first-order vacuum phase transitions through three-dimensional numerical simulations. We apply Bianchi Type-I metric to our model that has one scalar field minimally coupled to the gravity. We…

General Relativity and Quantum Cosmology · Physics 2023-08-01 A. Savaş Arapoğlu , A. Emrah Yükselci

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…

General Relativity and Quantum Cosmology · Physics 2026-04-13 Wen-Cong Gan , Leila L. Graef , Rudnei O. Ramos , Gustavo S. Vicente , Anzhong Wang

Homogeneous cosmological models with non-vanishing intrinsic curvature require a special treatment when they are quantized with loop quantum cosmological methods. Guidance from the full theory which is lost in this context can be replaced…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Martin Bojowald , Ghanashyam Date , Kevin Vandersloot

We study the late-time evolution of an anisotropic Bianchi-I universe with radiation in the framework of asymptotically safe gravity. We first discuss the radiation-dominated universe for the perfect fluid with the equation of state…

General Relativity and Quantum Cosmology · Physics 2026-04-24 Chiang-Mei Chen , Ting-Kui Fan , Rituparna Mandal , Nobuyoshi Ohta

Analytical and numerical methods are developed to analyze the quantum nature of the big bang in the setting of loop quantum cosmology. They enable one to explore the effects of quantum geometry both on the gravitational and matter sectors…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Abhay Ashtekar , Tomasz Pawlowski , Parampreet Singh

This article addresses the issue of estimating the duration in inflation in bouncing cosmology when anisotropies, inevitably playing an important role, are taken into account. It is shown that in Bianchi-I loop quantum cosmology, the higher…

General Relativity and Quantum Cosmology · Physics 2015-06-19 Linda Linsefors , Aurelien Barrau

We study the dynamics of the Bianchi I universe in modified loop quantum cosmology (mLQC-I) and uncover a robust mechanism for isotropization: the shear is dynamically suppressed after the bounce and decays rapidly in the quantum…

General Relativity and Quantum Cosmology · Physics 2026-05-26 Wen-Cong Gan , Leila L. Graef , Rudnei O. Ramos , Gustavo S. Vicente , Anzhong Wang

While loop quantum cosmology (LQC) predicts a robust quantum bounce of the background evolution of a Friedmann-Robertson-Walker (FRW) spacetime prior to the standard slow-roll inflation, whereby the big bang singularity is resolved, there…

General Relativity and Quantum Cosmology · Physics 2018-12-05 Qiang Wu , Tao Zhu , Anzhong Wang

We discuss the way non-perturbative quantization of cosmological spacetimes in loop quantum cosmology provides insights on the physics of Planck scale and the resolution of big bang singularity. In recent years, rigorous examination of…

General Relativity and Quantum Cosmology · Physics 2009-03-27 Parampreet Singh

An exactly solvable bounce model in loop quantum cosmology is identified which serves as a perturbative basis for realistic bounce scenarios. Its bouncing solutions are derived analytically, demonstrating why recent numerical simulations…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Martin Bojowald