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Related papers: The Dapor-Liegener model of Loop Quantum Cosmology…

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We study the quantum dynamics of de Sitter space formulated as a minisuperspace model with flat spatial hypersurfaces in unimodular gravity, both in the Wheeler-DeWitt approach and in loop quantum cosmology (LQC). Time evolution is defined…

General Relativity and Quantum Cosmology · Physics 2025-07-14 Steffen Gielen , Rita B. Neves

This introductory review is addressed to beginning researchers. Some of the distinguishing features of loop quantum gravity are illustrated through loop quantum cosmology of FRW models. In particular, these examples illustrate: i) how…

General Relativity and Quantum Cosmology · Physics 2010-11-11 Abhay Ashtekar

We present a detailed investigation of the cosmological dynamics based on $\exp (-R/{\Lambda})$ gravity. We apply the dynamical system approach to both the vacuum and matter cases and obtain exact solutions and their stability in the finite…

General Relativity and Quantum Cosmology · Physics 2008-11-26 M. Abdelwahab , S Carloni , P K. S. Dunsby

A new cosmic scenario with gravitationally induced particle creation is proposed. In this model the Universe evolves from an early to a late time de Sitter era, with the recent accelerating phase driven only by the negative creation…

General Relativity and Quantum Cosmology · Physics 2015-06-22 J. A. S. Lima , L. L. Graef , D. Pavón , S. Basilakos

A bouncing scenario of a flat homogeneous and isotropic universe is explored by using the reconstruction technique for the power-law parametrization of the Hubble parameter in a modified gravity theory with higher-order curvature and trace…

General Relativity and Quantum Cosmology · Physics 2023-04-03 J. K. Singh , Harshna Balhara , Kazuharu Bamba , J. Jena

We investigate a particular type of classical nonsingular bouncing cosmology, which results from general relativity if we allow for degenerate metrics. The simplest model has a matter content with a constant equation-of-state parameter and…

General Relativity and Quantum Cosmology · Physics 2019-10-23 F. R. Klinkhamer , Z. L. Wang

For the Poincare gauge theory of gravity we consider the dynamical scalar torsion mode in a cosmological context. We explore in particular the possibility of using dynamical torsion to explain the current state of the accelerating Universe.…

Astrophysics · Physics 2008-11-26 Hwei-Jang Yo , James M. Nester

At the level of heuristic effective dynamics, we investigate the cosmological inflation with holonomy corrections of loop quantum cosmology (LQC) in the $k=0$ Friedmann-Robertson-Walker model with a single inflaton field subject to a simple…

General Relativity and Quantum Cosmology · Physics 2010-04-29 Dah-Wei Chiou , Kai Liu

A union of matter bounce and Ekpyrotic scenarios is often studied in an attempt to combine the most promising features of these two models. Since non-perturbative quantum geometric effects in loop quantum cosmology (LQC) result in natural…

General Relativity and Quantum Cosmology · Physics 2021-03-31 Bao-Fei Li , Sahil Saini , Parampreet Singh

A new cosmological model based on the de Sitter gravity is investigated by dynamical analysis and numerical discussions. Via some transformations, the evolution equations of this model can form an autonomous system with 8 physical critical…

Cosmology and Nongalactic Astrophysics · Physics 2011-11-01 Xi-chen Ao , Xin-zhou Li , Ping Xi

Recent astronomical observations strongly indicate that the current Universe is undergoing an accelerated phase of expansion. The discovery of this fact was unexpected and resulted in the comeback of cosmological constant. The conception of…

General Relativity and Quantum Cosmology · Physics 2015-10-30 Marek Szydlowski , Pawel Tambor

We investigate the gravitational particle production in the bounce phase of Loop Quantum Cosmology (LQC). We perform both analytical and numerical analysis of the particle production process in a LQC scenario with Bunch-Davies vacuum…

General Relativity and Quantum Cosmology · Physics 2020-08-21 Leila L. Graef , Rudnei O. Ramos , Gustavo S. Vicente

I present a streamlined review of how the separate universe approach to cosmological perturbation theory can be used to study the dynamics of long-wavelength scalar perturbations in loop quantum cosmology, and then use it to calculate how…

General Relativity and Quantum Cosmology · Physics 2016-08-03 Edward Wilson-Ewing

Understanding the emergence of classical behavior from a quantum theory is vital to establishing the quantum origin for the temperature fluctuations observed in the Cosmic Microwave Background (CMB). We show that a real-space approach can…

General Relativity and Quantum Cosmology · Physics 2024-02-12 S. Mahesh Chandran , Karthik Rajeev , S. Shankaranarayanan

To derive loop quantum cosmology from loop quantum gravity, I apply the model given in \cite{lin1} to a system with coupled gravitational and matter fields. The matter sector consists of a scalar field $phi$ serving as a cosmological clock,…

General Relativity and Quantum Cosmology · Physics 2018-07-23 Chun-Yen Lin

Qualitative dynamics of three different loop quantizations of spatially flat isotropic and homogeneous models is studied using effective spacetime description of the underlying quantum geometry. These include the standard loop quantum…

General Relativity and Quantum Cosmology · Physics 2018-10-03 Bao-Fei Li , Parampreet Singh , Anzhong Wang

In the standard inflationary paradigm the inhomogeneities observed in the CMB arise from quantum fluctuations of an initially homogeneous and isotropic vacuum state. This picture suffers from two well-known weaknesses. First, it assumes…

General Relativity and Quantum Cosmology · Physics 2026-01-21 Gabriel R. Bengochea , Gabriel Leon , Alejandro Perez

We investigate the quantum Ricci curvature, which was introduced in earlier work, in full, four-dimensional quantum gravity, formulated nonperturbatively in terms of Causal Dynamical Triangulations (CDT). A key finding of the CDT approach…

High Energy Physics - Theory · Physics 2020-12-02 N. Klitgaard , R. Loll

Loop quantum cosmology is a symmetry-reduced application of loop quantum gravity. The theory predicts a bounce for the universe at the Planck scale and resolves the singularity of standard cosmology. The dynamics is also governed by an…

General Relativity and Quantum Cosmology · Physics 2024-06-27 Abolhassan Mohammadi

In this Letter, we study analytically the evolutions of the flat Friedmann-Lemaitre-Robertson-Walker (FLRW) universe and its linear perturbations in the framework of {\em the dressed metric approach} in loop quantum cosmology (LQC).…

General Relativity and Quantum Cosmology · Physics 2017-09-21 Tao Zhu , Anzhong Wang , Klaus Kirsten , Gerald Cleaver , Qin Sheng