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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…

General Relativity and Quantum Cosmology · Physics 2009-04-10 Marco Valerio Battisti

We analyze the semiclassical polymer dynamics of the inhomogeneous Mixmaster model by choosing the cubed scale factor as the discretized configurational variable, while the anisotropies remain pure Einsteinian variables. Such a modified…

General Relativity and Quantum Cosmology · Physics 2019-02-06 Stefano Antonini , Giovanni Montani

I investigate spacetime singularities from the point of view of the wavefunction of the universe. In order to extend the classical notion of geodesic incompleteness one has to include the proper time of an observer as a degree of freedom in…

General Relativity and Quantum Cosmology · Physics 2025-11-14 Federico Piazza

We study the anisotropic Bianchi I and Bianchi II models in vacuum in the framework of deformed commutation relations (DCRs). Working in a parametrisation of the spatial metric by a volume and two anisotropy variables, we propose modified…

General Relativity and Quantum Cosmology · Physics 2025-10-29 Gabriele Barca , Steffen Gielen

We show that the quantization ambiguities of loop quantum cosmology, when considered in wider generality, can be used to produce discretionary dynamical behavior. There is an infinite dimensional space of ambiguities which parallels the…

General Relativity and Quantum Cosmology · Physics 2023-05-03 Lautaro Amadei , Alejandro Perez , Salvatore Ribisi

In this paper, in an extended theory of gravity, we have presented bouncing cosmological model at the backdrop of an isotropic, homogeneous space-time, in presence of general relativistic hydrodynamics (GRH). The scale factor has been…

General Relativity and Quantum Cosmology · Physics 2023-03-29 A. Y. Shaikh , Sankarsan Tarai , S. K. Tripathy , B. Mishra

The present work deals with a FLRW cosmological model with spatial curvature and minimally coupled scalar field as the matter content. The curvature term behaves as a perfect fluid with the equation of state parameter w_K = -1/3 Using…

General Relativity and Quantum Cosmology · Physics 2024-07-09 Soumya Chakraborty , Sudip Mishra , Subenoy Chakraborty

A bouncing universe is a viable candidate to solve the initial singularity problem. Here we consider bouncing solutions in the context of $f(R,\mathcal{G})$ gravity by using an order reduction technique which allows one to find solutions…

General Relativity and Quantum Cosmology · Physics 2020-06-24 Bruno J. Barros , Elsa M. Teixeira , Daniele Vernieri

In this paper we explore how far the post-Newtonian theory goes in overcoming the difficulties associated with anisotropic homogeneous cosmologies in the Newtonian approximation. It will be shown that, unlike in the Newtonian case, the…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Tamath Rainsford

By quantizing the background as well as the perturbations in a simple one fluid cosmological model, we show that there exists an ambiguity in the choice of relevant variables, potentially leading to incompatible observational physical…

General Relativity and Quantum Cosmology · Physics 2022-03-09 Jaime de Cabo Martin

The singularity and inflationary problems have posed significant challenges for understanding the universe's origin and evolution. Bouncing cosmology has emerged as a promising alternative to standard cosmological models, offering a…

General Relativity and Quantum Cosmology · Physics 2025-07-28 A. Zhadyranova , M. Koussour , V. Zhumabekova , N. Zhusupova , S. Muminov , J. Rayimbaev

The present work analyzes the various conditions in which there can be a bouncing universe solution in f(R) gravity. In the article an interesting method, to analyze the bouncing FRW solutions in a spatially flat universe using f(R) gravity…

General Relativity and Quantum Cosmology · Physics 2014-12-09 Niladri Paul , Saikat Nil Chakrabarty , Kaushik Bhattacharya

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

We explore the possibility of realizing a non-singular bounce in the early universe within the framework of modified gravity with spacetime torsion. In Einstein Cartan theory, torsion is embedded in the spacetime by adding an antisymmetric…

General Relativity and Quantum Cosmology · Physics 2026-01-21 Sonej Alam , Somasri Sen , Soumitra Sengupta

Differences in pressure during expansion and contraction stages in cosmic evolution can result in a hysteresis-like phenomena in non-singular cyclic models sourced with scalar fields. We discuss this phenomena for spatially closed isotropic…

General Relativity and Quantum Cosmology · Physics 2020-04-22 John L. Dupuy , Parampreet Singh

In this paper we study quantum dynamics of the bouncing cosmological model. We focus on the model of the flat Friedman-Robertson-Walker universe with a free scalar field. The bouncing behavior, which replaces classical singularity, appears…

General Relativity and Quantum Cosmology · Physics 2013-06-12 Jean Pierre Gazeau , Jakub Mielczarek , Wlodzimierz Piechocki

In order to investigate if the anisotropy of the spacetime may induce future singularities at a finite value of the cosmic time on the evolution of cosmological models, we study vacuum and non-vacuum Bianchi type I spacetimes exhibiting…

General Relativity and Quantum Cosmology · Physics 2016-11-30 Mauricio Cataldo , Antonella Cid , Pedro Labraña , Patricio Mella

We provide an analytical solution to the quantum dynamics of a flat Friedmann-Lema\^itre- Robertson-Walker model with a massless scalar field in the presence of a small and positive cosmological constant, in the context of Loop Quantum…

General Relativity and Quantum Cosmology · Physics 2020-02-06 Mercedes Martín-Benito , Rita B. Neves

A class of $k$-Essence cosmological models, with a power law kinetic term, is quantised in the mini-superspace. It is shown that for a specific configuration, corresponding to a pressureless fluid, a Schr\"odinger-type equation is obtained…

General Relativity and Quantum Cosmology · Physics 2016-12-28 C. R. Almeida , J. C. Fabris , F. Sbisá , Y. Tavakoli

We analyze the dynamics of a Bianchi I cosmology in the presence of a viscous fluid, causally regularized according to the Lichnerowicz approach. We show how the effect induced by shear viscosity is still able to produce a matter creation…

General Relativity and Quantum Cosmology · Physics 2017-09-13 Giovanni Montani , Marta Venanzi