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A matter bouncing entropy-corrected cosmological model has been suggested. The model allows only positive curvature with negative pressure and no violation of the null energy condition. The result obtained in this paper is supported by some…

General Relativity and Quantum Cosmology · Physics 2022-10-12 Nasr Ahmed , Tarek M. Kamel , Mohamed I Nouh

In this article we review recent developments of cyclic cosmology. A typical non-singular cyclic model within General Relativity requires a non-conventional fluid with negative effective energy density, in order to cancel the matter…

General Relativity and Quantum Cosmology · Physics 2012-01-24 Yi-Fu Cai , Emmanuel N. Saridakis

In isotropic loop quantum cosmology, non-perturbatively modified dynamics of a minimally coupled scalar field violates weak, strong and dominant energy conditions when they are stated in terms of equation of state parameter. The violation…

General Relativity and Quantum Cosmology · Physics 2010-11-05 Golam Mortuza Hossain

Possible analogies between vacuum state and quantum fluid provide a model to study vacuum energy density induced by thermal corrections, space-time curvature, boundary conditions and quantum back-reaction. We find that vacuum energy density…

High Energy Physics - Theory · Physics 2012-06-19 J. A. Sanchez-Monroy , C. J. Quimbay

In this paper we study dynamics of the closed FRW model with holonomy corrections coming from loop quantum cosmology. We consider models with a scalar field and cosmological constant. In case of the models with cosmological constant and…

General Relativity and Quantum Cosmology · Physics 2009-11-19 Jakub Mielczarek , Orest Hrycyna , Marek Szydlowski

Using the improved quantization technique to the mini-superspace approximation of loop quantum gravity, we study the evolution of black holes supported by a cosmological constant. The addition of a cosmological constant allows for classical…

General Relativity and Quantum Cosmology · Physics 2009-11-06 J. Brannlund , S. Kloster , A. DeBenedictis

We discuss how a cyclic model for the flat universe can be constructively derived from Loop Quantum Gravity. This model has a lower bounce, at small values of the scale factor, which shares many similarities with that of Loop Quantum…

General Relativity and Quantum Cosmology · Physics 2017-06-13 Francesco Cianfrani , Jerzy Kowalski-Glikman , Giacomo Rosati

Quantum reduced loop gravity is designed to consistently study symmetry reduced systems within the loop quantum gravity framework. In particular, it bridges the gap between the effective cosmological models of loop quantum cosmology and the…

General Relativity and Quantum Cosmology · Physics 2018-12-05 Emanuele Alesci , Aurélien Barrau , Gioele Botta , Killian Martineau , Gabriele Stagno

As an alternative to the paradigm of slow roll inflation, we propose an extended scenario of the matter bounce cosmology in which the Universe has experienced a quasi-matter contracting phase with a variable background equation of state…

General Relativity and Quantum Cosmology · Physics 2015-09-04 Jaume de Haro , Yi-Fu Cai

We consider the matter bounce scenario in Loop Quantum Cosmology (LQC) for physical potentials that at early times provide a nearly matter dominated Universe in the contracting phase, having a reheating mechanism in the expanding phase,…

General Relativity and Quantum Cosmology · Physics 2015-06-19 Jaume Haro , Jaume Amorós

$Circuit~ Complexity$, a well known computational technique has recently become the backbone of the physics community to probe the chaotic behaviour and random quantum fluctuations of quantum fields. This paper is devoted to the study of…

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

In an expanding universe the vacuum energy density \rho_{\Lambda} is expected to be a dynamical quantity. In quantum field theory in curved space-time \rho_{\Lambda} should exhibit a slow evolution, determined by the expansion rate of the…

High Energy Physics - Phenomenology · Physics 2015-06-04 Harald Fritzsch , Joan Sola

Quantum treatment of physical reference frame leads to the Ricci flow of quantum spacetime, which is a quite rigid framework to quantum and renormalization effect of gravity. The theory has a low characteristic energy scale described by a…

General Relativity and Quantum Cosmology · Physics 2023-04-27 M. J. Luo

The five-dimensional loop quantum Kaluza-Klein cosmology is constructed based on the symmetric reduction of the connection formulation of the full theory. Through semiclassical analysis, the effective scalar constraint for the cosmological…

General Relativity and Quantum Cosmology · Physics 2026-02-20 Shengzhi Li , Yongge Ma , Faqiang Yuan , Xiangdong Zhang

The discrete quantum geometric effects play an important role in dynamical evolution in the loop quantum cosmology. These effects which are significant at the high energies lead to the quadratic energy density modifications to the Friedmann…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Parampreet Singh

In contrast to scalar and tensor modes, vector modes of linear perturbations around an expanding Friedmann--Robertson--Walker universe decay. This makes them largely irrelevant for late time cosmology, assuming that all modes started out at…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Martin Bojowald , Golam Mortuza Hossain

The energy density of the universe today may be dominated by the vacuum energy of a slowly rolling scalar field. Making a quantum expansion around such a time dependent solution is found to break fundamental symmetries of quantum field…

High Energy Physics - Phenomenology · Physics 2008-11-26 Pankaj Jain , Subhadip Mitra

The dynamics of expansion of the Universe and evolution of scalar perturbations are studied for the quintessential scalar fields $Q$ with the classical Lagrangian satisfying the additional condition $w=const$ or $c^2_a=0$. Both…

Astrophysics · Physics 2009-08-10 B. Novosyadlyj , O. Sergijenko

Loop quantum cosmology (LQC) is very powerful to deal with the behavior of early universe. And the effective loop quantum cosmology gives a successful description of the universe in the semiclassical region. We consider the apparent horizon…

General Relativity and Quantum Cosmology · Physics 2010-04-15 Li-Fang Li , Jian-Yang Zhu
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