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The cosmological primordial power spectrum is known to be one of the most promising observable to probe quantum gravity effects. In this article, we investigate how the tensor power spectrum is modified by Loop Quantum Gravity corrections.…

General Relativity and Quantum Cosmology · Physics 2010-04-06 J. Grain , T. Cailleteau , A. Barrau , A. Gorecki

In this paper we study possible observational consequences of the bouncing cosmology. We consider a model where a phase of inflation is preceded by a cosmic bounce. While we consider in this paper only that the bounce is due to loop quantum…

General Relativity and Quantum Cosmology · Physics 2014-11-21 Jakub Mielczarek , Michal Kamionka , Aleksandra Kurek , Marek Szydlowski

We study quantum cosmology with conformal matter comprising a perfect radiation fluid and a number of conformally coupled scalar fields. Focusing initially on the collective coordinates (minisuperspace) associated with homogeneous,…

High Energy Physics - Theory · Physics 2016-07-07 Steffen Gielen , Neil Turok

The global dynamics of a homogeneous universe in Loop Quantum Cosmology is viewed as a scattering process of its geometrodynamical equivalent. This picture is applied to build a flexible (easy to generalize) and not restricted just to…

General Relativity and Quantum Cosmology · Physics 2010-04-22 Wojciech Kaminski , Tomasz Pawlowski

This brief article sums up the possible imprints of loop quantum gravity effects on the cosmological microwave background. We focus on semi-classical terms and show that "Big Bounce" corrections, together with the "pre Big Bounce" state,…

General Relativity and Quantum Cosmology · Physics 2018-12-19 Aurelien Barrau

In order to investigate the potential observational signals of different regularization ambiguities in loop quantum cosmological models, we systematically compute and compare the primordial scalar power spectra and the resulting angular…

General Relativity and Quantum Cosmology · Physics 2024-08-30 Bao-Fei Li , Meysam Motaharfar , Parampreet Singh

Cosmological models where the standard big bang is replaced by a bounce have been studied for decades. The situation has, however, dramatically changed in the past years for two reasons: first, because new ways to probe the early Universe…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-17 J. Grain , A. Barrau , T. Cailleteau , J. Mielczarek

Problem of cosmological singularity of general relativity theory is discussed. The possible resolution of this problem in the framework of inflationary cosmology is proposed. Physical conditions leading to bouncing inflationary solutions in…

General Relativity and Quantum Cosmology · Physics 2007-05-23 A. V. Minkevich

Loop Quantum Gravity is a theory that attempts to describe the quantum mechanics of the gravitational field based on the canonical quantization of General Relativity. According to Loop Quantum Gravity, in a gravitational field, geometric…

General Relativity and Quantum Cosmology · Physics 2021-12-16 W. F. Chagas-Filho

We derive the primordial power spectra and spectral indexes of the density fluctuations and gravitational waves in the framework of loop quantum cosmology (LQC) with holonomy and inverse-volume corrections, by using the uniform asymptotic…

General Relativity and Quantum Cosmology · Physics 2015-08-04 Tao Zhu , Anzhong Wang , Gerald Cleaver , Klaus Kirsten , Qin Sheng , Qiang Wu

The investigation of quantum gravity effects in order to avoid the big bang singularity is a requisite, so that the idea of oscillating universes is introduced as an alternative for standard cosmological model. Therefore, the Friedmann…

General Relativity and Quantum Cosmology · Physics 2018-04-18 Amin. Salehi , Mojtaba. Mahmoudi fard

The Pre-Big Bang cosmology inspired generations of cosmologists in attempts to cure the initial Big Bang singularity using a fundamental length scale as proposed by String Theory. The existence of a phase of collapse/inflation with…

General Relativity and Quantum Cosmology · Physics 2022-07-14 V. Bozza

We give a prescription to define in Loop Quantum Gravity the electric field operator related to the scale factor of an homogeneous and isotropic cosmological space-time. This procedure allows to link the fundamental theory with its…

General Relativity and Quantum Cosmology · Physics 2014-11-21 Francesco Cianfrani , Giovanni Montani

We review some recent progress in the extraction of inflationary observables in loop quantum cosmology. Inverse-volume quantum corrections induce a growth of power in the large-scale cosmological spectra and are constrained by observations.

General Relativity and Quantum Cosmology · Physics 2012-05-23 Gianluca Calcagni

Using techniques from loop quantum gravity, the standard theory of cosmological perturbations was recently generalized to encompass the Planck era. We now apply this framework to explore pre-inflationary dynamics. The framework enables us…

General Relativity and Quantum Cosmology · Physics 2015-03-12 Ivan Agullo , Abhay Ashtekar , William Nelson

We study slow-roll inflation driven by a scalar field non-minimally coupled to gravity within the effective framework of Loop Quantum Cosmology (LQC), including inverse-volume corrections. We consider two physically motivated classes of…

General Relativity and Quantum Cosmology · Physics 2026-03-05 Rudranil Roy , Giovanni Otalora , Joel Saavedra , Salvatore Capozziello

We investigate the emergence of a quantum Big-Bounce in the context of an isotropic Universe, filled by a self-interacting scalar field, which plays the role of a physical clock. The bouncing cosmology is the result of a scattering process,…

General Relativity and Quantum Cosmology · Physics 2024-10-04 S. Lo Franco , G. Montani

In this paper we investigate gravitational waves production during the Big Bounce phase inspired by the Loop Quantum Cosmology. We consider the influence of the holonomy corrections to the equation for tensor modes. We show that they act…

General Relativity and Quantum Cosmology · Physics 2014-11-18 Jakub Mielczarek

In this paper we study the flat (k=0) cosmological FRW model with holonomy corrections of Loop Quantum Gravity. The considered universe contains a massless scalar field and the cosmological constant Lambda. We find analytical solutions for…

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

Loop quantum cosmology of the k=0 FRW model (with a massless scalar field) is shown to be exactly soluble if the scalar field is used as the internal time already in the classical Hamiltonian theory. Analytical methods are then used i) to…

General Relativity and Quantum Cosmology · Physics 2010-04-23 Abhay Ashtekar , Alejandro Corichi , Parampreet Singh