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We analyze the big bounce transition of the quantum FRW model in the setting of the nonstandard loop quantum cosmology (LQC). Elementary observables are used to quantize composite observables. The spectrum of the energy density operator is…

General Relativity and Quantum Cosmology · Physics 2011-03-28 Przemyslaw Malkiewicz , Wlodzimierz Piechocki

Since there are quantization ambiguities in constructing the Hamiltonian constraint operator in isotropic loop quantum cosmology, it is crucial to check whether the key features of loop quantum cosmology are robust against the ambiguities.…

General Relativity and Quantum Cosmology · Physics 2010-04-14 Jinsong Yang , You Ding , Yongge Ma

This article presents an "in-a-nutshell" yet self-contained introductory review on loop quantum gravity (LQG) -- a background-independent, nonperturbative approach to a consistent quantum theory of gravity. Instead of rigorous and…

General Relativity and Quantum Cosmology · Physics 2014-12-30 Dah-Wei Chiou

We discuss the effects of a (possibly) negative $(1+z)^6$ type contribution to the Friedmann equation. No definite answer can be given as to the presence and magnitude of a particular mechanism, because any test using the general relation…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Tomasz Stachowiak , Marek Szydlowski

We analyze the big bounce transition of the quantum FRW model in the setting of the nonstandard loop quantum cosmology (LQC). Elementary observables are used to quantize compound observables. The spectrum of the energy density operator is…

General Relativity and Quantum Cosmology · Physics 2015-05-20 Wlodzimierz Piechocki

One of the qualitatively distinct and robust implication of Loop Quantum Gravity (LQG) is the underlying discrete structure. In the cosmological context elucidated by Loop Quantum Cosmology (LQC), this is manifested by the Hamiltonian…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Kinjal Banerjee , Ghanashyam Date

We study the effective cosmological dynamics, emerging as the hydrodynamics of simple condensate states, of a group field theory model for quantum gravity coupled to a massless scalar field and reduced to its isotropic sector. The quantum…

General Relativity and Quantum Cosmology · Physics 2016-11-23 Daniele Oriti , Lorenzo Sindoni , Edward Wilson-Ewing

In this article, we study the equations driving the dynamics of a Bianchi-I universe described by holonomy corrected effective loop quantum cosmology. We derive the LQC-modified generalized Friedmann equation, which is used as a guide to…

General Relativity and Quantum Cosmology · Physics 2014-07-28 Linda Linsefors , Aurelien Barrau

Despite its great successes in accounting for the current observations, the so called `standard' model of cosmology faces a number of fundamental unresolved questions. Paramount among these are those relating to the nature of the origin of…

General Relativity and Quantum Cosmology · Physics 2008-02-29 Martin Bojowald , Reza Tavakol

We develop a Gauss-Bonnet extension of Loop Quantum Cosmology, by introducing holonomy corrections in modified $F(\mathcal{G})$ theories of gravity. Within the context of our formalism, we provide a perturbative expansion in the critical…

General Relativity and Quantum Cosmology · Physics 2015-12-16 J. Haro , A. N. Makarenko , A. N. Myagky , S. D. Odintsov , V. K. Oikonomou

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

The first-order loop quantum gravity correction of the simplest, classical general-relativistic Friedmann Hamiltonian constraint, emerging from a holomorphic spinfoam cosmological model peaked on homogeneous, isotropic geometries, is…

General Relativity and Quantum Cosmology · Physics 2015-07-02 Christian Röken

The primordial Universe can be used as a laboratory to set constraints on quantum gravity. In the framework of Loop Quantum Cosmology, we show that such a proposal for quantum gravity not only solves for the big bang singularity issue but…

General Relativity and Quantum Cosmology · Physics 2012-06-08 Julien Grain

The big bounce (BB) transition within a flat Friedmann-Robertson-Walker model is analyzed in the setting of loop geometry underlying the loop cosmology. We solve the constraint of the theory at the classical level to identify physical phase…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Piotr Dzierzak , Przemyslaw Malkiewicz , Wlodzimierz Piechocki

We compute second-order quantum corrections, as quantum dispersions and correlations, to a cosmological model coupling a single scalar perturbation mode to a bouncing background within Loop Quantum Cosmology (LQC). Using an effective…

General Relativity and Quantum Cosmology · Physics 2026-05-19 Héctor Hernández Hernández , Hugo Morales Técotl , Gustavo Sánchez Herrera

The standard model of cosmology assumes a homogeneous and isotropic universe that undergoes a period of exponential expansion very early on, named inflation. This stretches quantum fluctuations from the onset of inflation to cosmological…

General Relativity and Quantum Cosmology · Physics 2024-10-22 Rita B. Neves

We examine Friedmann-Lema\^itre-Robertson-Walker cosmology, incorporating quantum gravitational corrections through the functional renormalization group flow of the effective action for gravity. We solve the Einstein equation with quantum…

General Relativity and Quantum Cosmology · Physics 2025-10-15 Chiang-Mei Chen , Rituparna Mandal , Nobuyoshi Ohta

We study the loop quantum cosmology of a flat Friedmann-Lemaitre-Robertson-Walker space-time with a Maxwell field. We show that many of the qualitative properties derived for the case of a massless scalar field also hold for a Maxwell…

General Relativity and Quantum Cosmology · Physics 2015-01-07 Tomasz Pawlowski , Roberto Pierini , Edward Wilson-Ewing

The effective approach in Loop Quantum Cosmology (LQC) has provided means to obtain predictions for observable quantities in LQC models. While an effective dynamics in LQC has been extensively considered in different scenarios, a robust…

General Relativity and Quantum Cosmology · Physics 2022-08-11 Gustavo S. Vicente , Rudnei O. Ramos , Leila L. Graef

An exactly solvable bounce model in loop quantum cosmology is identified which serves as a perturbative basis for realistic bounce scenarios. Its bouncing solutions are derived analytically, demonstrating why recent numerical simulations…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Martin Bojowald
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