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We present a review on basic aspects of quantum cosmology in the presence of cut-off physics. We first analyze how the Wheeler-DeWitt equation in a pure metric approach describes the quantum Universe, showing how the singularity is not…

General Relativity and Quantum Cosmology · Physics 2021-09-20 Gabriele Barca , Eleonora Giovannetti , Giovanni Montani

We investigate quantum cosmological models in an n-dimensional anisotropic universe in the presence of a massless scalar field. Our basic inspiration comes from Chodos and Detweiler's classical model which predicts an interesting behaviour…

General Relativity and Quantum Cosmology · Physics 2018-02-14 F. A. P. Alves-Júnior , M. L. Pucheu , A. B. Barreto , C. Romero

The dynamics and evolution of Bianchi type I space-times is considered in the framework of the four-dimensional truncation of a reduced theory obtained from the N=2,D=5 supergravity. The general solution of the gravitational field equations…

High Energy Physics - Theory · Physics 2009-10-31 Chiang-Mei Chen , T. Harko , M. K. Mak

We study stability conditions of the full Hamiltonian constraint equation describing the quantum dynamics of the diagonal Bianchi I model in the context of LQC. Our analysis has shown robust evidence of an instability in the explicit…

General Relativity and Quantum Cosmology · Physics 2009-11-06 William Nelson , Mairi Sakellariadou

Loop quantum cosmology homogeneous models with a massless scalar field show that the big-bang singularity can be replaced by a big quantum bounce. To gain further insight on the nature of this bounce, we study the semi-discrete loop quantum…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Pablo Laguna

The detailed formulation for loop quantum cosmology (LQC) in the Bianchi I model with a scalar massless field has been constructed. In this paper, its effective dynamics is studied in two improved strategies for implementing the LQC…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Dah-Wei Chiou

In this work we study the dynamics of the axisymmetric Bianchi IX cosmological model with a term of quantum potential added. As it is well known this class of Bianchi IX models are homogeneous and anisotropic with two scale factors, $A(t)$…

General Relativity and Quantum Cosmology · Physics 2010-05-25 G. C. Corrêa , T. J. Stuchi , S. E. Jorás

In this paper, we investigate anisotropic cosmological solutions within the framework of Born-Infeld-f(R) gravity, a modification of general relativity that incorporates higher-order curvature invariants. Specifically, we focus on the…

General Relativity and Quantum Cosmology · Physics 2025-01-06 Salih Kibaroğlu

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

In this paper we introduce a numerical approximation technique to obtain pre-classical solutions to models of loop quantum gravity. In particular, we apply the technique to vacuum Bianchi I cosmological models and recover known solutions.…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Seth Connors , Gaurav Khanna

We introduce a new framework for loop quantum gravity: mimicking the spinfoam quantization procedure we propose to study the symmetric sectors of the theory imposing the reduction weakly on the full kinematical Hilbert space of the…

General Relativity and Quantum Cosmology · Physics 2015-06-12 Emanuele Alesci , Francesco Cianfrani

This paper is a study of the effects of anisotropic matter sources on the qualitative evolution of spatially homogenous cosmologies of Bianchi type VIII. The analysis is based on a dynamical system approach and makes use of an anisotropic…

General Relativity and Quantum Cosmology · Physics 2015-06-04 Gernot Heißel

We consider a Bianchi type III axisymmetric geometry in the presence of an electromagnetic field. A first result at the classical level is that the symmetry of the geometry need not be applied on the electromagnetic tensor $F_{\mu\nu}$; the…

General Relativity and Quantum Cosmology · Physics 2018-04-04 A. Karagiorgos , T. Pailas , N. Dimakis , Petros A. Terzis , T. Christodoulakis

The observational evidence regarding the present cosmological aspects tells us about the presence of very little anisotropy in the universe on a large scale. Here, in this paper, we attempt to study locally rotationally symmetric (LRS)…

General Relativity and Quantum Cosmology · Physics 2022-11-02 N. S. Kavya , V. Venkatesha , Sanjay Mandal , P. K. Sahoo

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…

General Relativity and Quantum Cosmology · Physics 2017-08-02 Riccardo Moriconi , Giovanni Montani

We study the scalar modes of linear perturbations in loop quantum cosmology. This is done on a lattice where each cell is taken to be homogeneous and isotropic and can be quantized via standard homogeneous loop quantum cosmology techniques.…

General Relativity and Quantum Cosmology · Physics 2015-06-05 Edward Wilson-Ewing

In the loop quantum cosmology effective dynamics for the vacuum Bianchi type I and type IX space-times, a non-singular bounce replaces the classical singularity. The bounce can be approximated as an instantaneous transition between two…

General Relativity and Quantum Cosmology · Physics 2020-01-08 Edward Wilson-Ewing

Loop Quantum Cosmology (LQC), mainly due to Bojowald, is not the cosmological sector of Loop Quantum Gravity (LQG). Rather, LQC consists of a truncation of the phase space of classical General Relativity to spatially homogeneous situations…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Johannes Brunnemann , Thomas Thiemann

The loop quantum cosmology of the Bianchi type II string cosmological model in the presence of a homogeneous magnetic field is studied. We present the effective equations which provide modifications to the classical equations of motion due…

General Relativity and Quantum Cosmology · Physics 2015-05-01 Victor Rikhvitsky , Bijan Saha , Mihai Visinescu

Due to the numerical complexities of studying evolution in an anisotropic quantum spacetime, in comparison to the isotropic models, the physics of loop quantized anisotropic models has remained largely unexplored. In particular, robustness…

General Relativity and Quantum Cosmology · Physics 2017-04-14 Peter Diener , Anton Joe , Miguel Megevand , Parampreet Singh