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In this paper we investigate tensor modes of perturbations in the universe governed by Loop Quantum Cosmology. We derive the equation for tensor modes and investigate numerically effects of quantum corrections. This investigation reveals…

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

We investigate the consequences of different regularizations and ambiguities in loop cosmological models on the predictions in the scalar and tensor primordial spectrum of the cosmic microwave background using the dressed metric approach.…

General Relativity and Quantum Cosmology · Physics 2020-04-08 Bao-Fei Li , Parampreet Singh , Anzhong Wang

Loop Quantum Gravity is a nonperturbative and background independent program for the quantization of General Relativity. Its underlying formalism has been applied successfully to the study of cosmological spacetimes, both to test the…

General Relativity and Quantum Cosmology · Physics 2021-09-13 Beatriz Elizaga Navascués , Guillermo A. Mena Marugán

We investigate the behaviour of tensor fluctuations in Loop Quantum Cosmology, focusing on a class of scaling solutions which admit a near scale-invariant scalar field power spectrum. We obtain the spectral index of the gravitational field…

Astrophysics · Physics 2009-01-21 E. J. Copeland , D. J. Mulryne , N. J. Nunes , M. Shaeri

In this work, we compute the time-dependent masses that govern the dynamics of scalar and tensor perturbations propagating on an effective flat, homogeneous, and isotropic background within the framework of loop quantum cosmology,…

General Relativity and Quantum Cosmology · Physics 2020-12-10 Alejandro García-Quismondo , Guillermo A. Mena Marugán , Gabriel Sánchez Pérez

In the framework of Loop Quantum Cosmology, inhomogeneous models are usually quantized by means of a hybrid approach that combines loop quantization techniques with standard quantum field theory methods. This approach is based on a…

General Relativity and Quantum Cosmology · Physics 2016-08-23 B. Elizaga Navascués , M. Martín-Benito , G. A. Mena Marugán

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 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

The era of precision cosmology has allowed us to accurately determine many important cosmological parameters, in particular via the CMB. Confronting Loop Quantum Cosmology with these observations provides us with a powerful test of the…

General Relativity and Quantum Cosmology · Physics 2012-04-06 Ivan Agullo , Abhay Ashtekar , William Nelson

We study cosmological perturbations in the framework of Loop Quantum Cosmology, using a hybrid quantization approach and Mukhanov-Sasaki variables. The formulation in terms of these gauge invariants allows one to clarify the independence of…

General Relativity and Quantum Cosmology · Physics 2014-09-17 Laura Castelló Gomar , Mikel Fernández-Méndez , Guillermo A. Mena Marugán , Javier Olmedo

In this paper we consider tensor perturbations produced at a bounce phase in presence of the holonomy corrections. Here bounce phase and holonomy corrections originate from Loop Quantum Cosmology. We re-derive formulas for the corrections…

General Relativity and Quantum Cosmology · Physics 2009-07-09 Jakub Mielczarek

In this paper, we first provide a brief review of the effective dynamics of two recently well-studied models of modified loop quantum cosmologies (mLQCs), which arise from different regularizations of the Hamiltonian constraint and show the…

General Relativity and Quantum Cosmology · Physics 2021-06-25 Bao-Fei Li , Parampreet Singh , Anzhong Wang

We compare the primordial scalar power spectra in the loop cosmological models using the effective dynamics of the hybrid approach to cosmological perturbations in which the background is loop quantized but the perturbations are Fock…

General Relativity and Quantum Cosmology · Physics 2021-01-04 Bao-Fei Li , Javier Olmedo , Parampreet Singh , Anzhong Wang

Together with holonomy corrections, inverse volume terms should be taken into account when studying the primordial universe in loop quantum cosmology. We investigate how the tensor power spectrum is modified with respect to the standard…

General Relativity and Quantum Cosmology · Physics 2013-05-29 J. Grain , A. Barrau , A. Gorecki

Anomaly-free perturbations of loop quantum cosmology with holonomy corrections reveal an $\Omega$ -deformed spacetime structure, $\Omega:=1-2\rho/\rho_c$, where $\Omega<0$ indicates a Euclidean-like space and $\Omega>0$ indicates a…

General Relativity and Quantum Cosmology · Physics 2016-12-21 Long Chen , Jian-Yang Zhu

In the inflationary scenario of loop quantum cosmology in the presence of inverse-volume corrections, we give analytic formulas for the power spectra of scalar and tensor perturbations convenient to compare with observations. Since…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-18 Martin Bojowald , Gianluca Calcagni , Shinji Tsujikawa

We study the evolution of cosmological perturbations, using a hybrid approximation scheme which upgrades the weak-field limit of Einstein's field equations to account for post-Newtonian scalar and vector metric perturbations and for…

Astrophysics · Physics 2007-05-23 Carmelita Carbone , Sabino Matarrese

We provide an exhaustive numerical exploration of the predictions of loop quantum cosmology (LQC) with a post-bounce phase of inflation for the primordial power spectrum of scalar and tensor perturbations. We extend previous analysis by…

General Relativity and Quantum Cosmology · Physics 2015-12-30 Ivan Agullo , Noah A. Morris

Cosmological perturbations in Loop Quantum Cosmology (LQC) are usually studied incorporating either holonomy corrections, where the Ashtekar connection is replaced by a suitable sinus function in order to have a well-defined quantum…

General Relativity and Quantum Cosmology · Physics 2015-06-17 Jaime Haro

In this Essay we investigate the observational signatures of Loop Quantum Cosmology (LQC) in the CMB data. First, we concentrate on the dynamics of LQC and we provide the basic cosmological functions. We then obtain the power spectrum of…

General Relativity and Quantum Cosmology · Physics 2017-11-22 Spyros Basilakos , Vahid Kamali , Ahmad Mehrabi