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The existence of a quantum bounce in isotropic spacetimes is a key result in loop quantum cosmology (LQC), which has been demonstrated to arise in all the models studied so far. In most of the models, the bounce has been studied using…

General Relativity and Quantum Cosmology · Physics 2017-06-20 Peter Diener , Brajesh Gupt , Parampreet Singh

A lattice version of quantum nonlinear Schrodinger (NLS) equation is considered, which has significantly simple form and fullfils most of the criteria desirable for such lattice variants of field models. Unlike most of the known lattice…

High Energy Physics - Theory · Physics 2009-10-28 A Kundu , Orlando Ragnisco

We investigate the application of efficient recursive numerical integration strategies to models in lattice gauge theory from quantum field theory. Given the coupling structure of the physics problems and the group structure within lattice…

High Energy Physics - Lattice · Physics 2021-12-10 Tobias Hartung , Karl Jansen , Frances Y. Kuo , Hernan Leövey , Dirk Nuyens , Ian H. Sloan

This paper presents solutions to Einstein's equation -- and the numerical methods used to construct them -- that describe simple cosmological models on manifolds with compact non-orientable spatial slices. These solutions have been…

General Relativity and Quantum Cosmology · Physics 2026-04-28 Fan Zhang , Lee Lindblom

Applications of Riemannian quantum geometry to cosmology have had notable successes. In particular, the fundamental discreteness underlying quantum geometry has led to a natural resolution of the big bang singularity. However, the precise…

General Relativity and Quantum Cosmology · Physics 2011-05-05 Abhay Ashtekar , Martin Bojowald , Jerzy Lewandowski

We consider a class of Fuchsian equations that, for instance, describes the evolution of compressible fluid flows on a cosmological spacetime. Using the method of lines, we introduce a numerical algorithm for the singular initial value…

General Relativity and Quantum Cosmology · Physics 2021-03-17 Florian Beyer , Philippe G. LeFloch

We establish an algorithm that produces a new solution to the Einstein field equations, with an anisotropic matter distribution, from a given seed isotropic solution. The new solution is expressed in terms of integrals of known functions,…

General Relativity and Quantum Cosmology · Physics 2007-05-23 S. D. Maharaj , M. Chaisi

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

The improved dynamics of loop quantum cosmology is extended to include the Bianchi type II model. Because these space-times admit both anisotropies and non-zero spatial curvature, certain technical difficulties arise over and above those…

General Relativity and Quantum Cosmology · Physics 2010-01-07 Abhay Ashtekar , Edward Wilson-Ewing

We have recently constructed a numerical code that evolves a spherically symmetric spacetime using a hyperbolic formulation of Einstein's equations. For the case of a Schwarzschild black hole, this code works well at early times, but…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Mark A. Scheel , Thomas W. Baumgarte , Gregory B. Cook , Stuart L. Shapiro , Saul A. Teukolsky

We consider quantum (unitary) continuous time evolution of spins on a lattice together with quantum evolution of the lattice itself. In physics such evolution was discussed in connection with quantum gravity. It is also related to what is…

Mathematical Physics · Physics 2015-06-26 V. A. Malyshev

Building on hybrid quantum lattice gas algorithm, we revisit the possibilities of this quantum lattice model. By deriving a correction to the predicted viscosity, we provide analytical and numerical results that refine original formulation.…

Quantum Physics · Physics 2026-02-20 Niccoló Fonio , Pierre Sagaut , Giuseppe Di Molfetta

The quantum evolution equation of Loop Quantum Cosmology (LQC) -- the quantum Hamiltonian constraint -- is a difference equation. We relate the LQC constraint equation in vacuum Bianchi I separable (locally rotationally symmetric) models…

General Relativity and Quantum Cosmology · Physics 2013-01-25 Christine C. Dantas

We consider a broad class of static, spherically symmetric generalized Schwarzschild-like solutions with multiple non-interacting anisotropic fluid sources and derive the coordinate transformation from Schwarzschild-like (curvature) to…

General Relativity and Quantum Cosmology · Physics 2026-03-24 Zeyu Zeng , Elena Kopteva

The second Bianchi identity can be recast as an evolution equation for the Riemann curvatures. Here we will report on such a system for a vacuum static spherically symmetric spacetime. This is the first of two papers. In the following paper…

General Relativity and Quantum Cosmology · Physics 2013-05-30 Leo Brewin

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 interior of a Schwarzschild black hole is investigated at the level of phenomenological dynamics with the discreteness corrections of loop quantum geometry implemented in two different improved quantization schemes. In one scheme, the…

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

The loop quantization of the conformal Brans-Dicke cosmology is explored in the spatially flat and Bianchi-I setting. The scalar and conformal constraints governing the canonical model are quantized using the loop techniques. The physical…

General Relativity and Quantum Cosmology · Physics 2023-12-29 Chun-Yen Lin , Xiangjing Liu , Yongge Ma , Cong Zhang

We describe quantization schemes for scalar field cosmology in the metric variables with fundamental discreteness imposed with a lattice. The variables chosen for quantization determine the lattice, and each lattice produces distinct…

General Relativity and Quantum Cosmology · Physics 2025-07-18 Mustafa Saeed , Viqar Husain

We study the "improved dynamics" for the treatment of spherically symmetric space-times in loop quantum gravity introduced by Chiou {\em et al.} in analogy with the one that has been constructed by Ashtekar, Pawlowski and Singh for the…

General Relativity and Quantum Cosmology · Physics 2020-10-28 R. Gambini , J. Olmedo , J. Pullin