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In this paper we continue a study of cosmological perturbations in the conformal gravity theory. In previous work we had obtained a restricted set of solutions to the cosmological fluctuation equations, solutions that were required to be…

General Relativity and Quantum Cosmology · Physics 2019-05-08 Asanka Amarasinghe , Matthew G. Phelps , Philip D. Mannheim

We consider the symmetric teleparallel $f\left( Q\right) $-gravity in Friedmann--Lema\^{\i}tre--Robertson--Walker cosmology with nonzero spatial curvature. For a nonlinear $f\left( Q\right) $ model there exist always the limit of General\…

General Relativity and Quantum Cosmology · Physics 2023-10-09 Andronikos Paliathanasis

In this paper, we have shown the matter bounce scenario of the Universe in an extended symmetric teleparallel gravity, the f(Q) gravity. Motivated from the bouncing scenario and loop quantum cosmology (LQC), the form of the function $f(Q)$…

General Relativity and Quantum Cosmology · Physics 2023-02-06 A. S. Agrawal , B. Mishra , P. K. Agrawal

In the macroscopic gravity approach to the averaging problem in cosmology, the Einstein field equations on cosmological scales are modified by appropriate gravitational correlation terms. We study the averaging problem within the class of…

General Relativity and Quantum Cosmology · Physics 2008-11-26 A. A. Coley , N. Pelavas

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

We argue that the anomalous power asymmetry observed in the cosmic microwave background (CMB) may have originated in a cosmic bounce preceding inflation. In loop quantum cosmology (LQC) the big bang singularity is generically replaced by a…

General Relativity and Quantum Cosmology · Physics 2015-09-30 Ivan Agullo

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 the evolution of a homogeneous and isotropic spacetime whose spatial sections have three-torus topology, coupled to a massless scalar field with small scalar perturbations within loop quantum cosmology. We consider a proposal for…

General Relativity and Quantum Cosmology · Physics 2014-12-11 Mikel Fernández-Méndez , Guillermo A. Mena Marugán , Javier Olmedo

We discuss the most general field equations for cosmological spacetimes for theories of gravity based on non-linear extensions of the non-metricity scalar and the torsion scalar. Our approach is based on a systematic symmetry-reduction of…

General Relativity and Quantum Cosmology · Physics 2022-01-05 Fabio D'Ambrosio , Lavinia Heisenberg , Simon Kuhn

We study the quantum-gravitational corrections to the power spectrum of a gauge-invariant inflationary scalar perturbations in a closed model of a universe. We consider canonical quantum gravity as an approach to quantizing gravity. This…

General Relativity and Quantum Cosmology · Physics 2023-02-15 Tatevik Vardanyan , Claus Kiefer

This is the fourth paper in a series of four in which we use space adiabatic methods in order to incorporate backreactions among the homogeneous and between the homogeneous and inhomogeneous degrees of freedom in quantum cosmological…

General Relativity and Quantum Cosmology · Physics 2019-09-17 S. Schander , T. Thiemann

The Hamiltonian approach to cosmological perturbations in general relativity in finite space-time is developed, where a cosmological scale factor is identified with spatial averaging the metric determinant logarithm. This identification…

High Energy Physics - Theory · Physics 2009-11-11 B. M. Barbashov , V. N. Pervushin , A. F. Zakharov , V. A. Zinchuk

The relation between standard Loop Quantum Cosmology and full Loop Quantum Gravity fails already at the first nontrivial step: The configuration space of Loop Quantum Cosmology can not be embedded into the configuration space of full Loop…

General Relativity and Quantum Cosmology · Physics 2012-03-13 Johannes Brunnemann , Tim A. Koslowski

This thesis investigates the characteristics of modified teleparallel gravity models that incorporate a scalar field and a trace of the energy-momentum tensor, with particular attention to their cosmological effects, especially regarding…

General Relativity and Quantum Cosmology · Physics 2025-10-06 L K Duchaniya

A simple idea of relating the LQG and LQC degrees of freedom is discussed in context of toroidal Bianchi I model. The idea is an expansion of the construction originally introduced by Ashtekar and Wilson-Ewing and relies on explicit…

General Relativity and Quantum Cosmology · Physics 2015-12-16 Tomasz Pawłowski

We present quantum (and classical) Bianchi I model, with free massless scalar field, of the Universe. Our model may be treated as the simplest prototype of the quantum BKL (Belinskii-Khalatnikov-Lifshitz) scenario. The quantization is done…

General Relativity and Quantum Cosmology · Physics 2011-05-03 Piotr Dzierzak

A model for a flat isotropic universe with a negative cosmological constant $\Lambda$ and a massless scalar field as sole matter content is studied within the framework of Loop Quantum Cosmology. By application of the methods introduced for…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Eloisa Bentivegna , Tomasz Pawlowski

We study one-loop corrections to the two-point correlation function of tensor perturbations in primordial cosmology induced by massless spectator matter fields. Using the Schwinger-Keldysh formalism in cosmological perturbation theory, we…

General Relativity and Quantum Cosmology · Physics 2020-11-02 H. S. Tan

We study the hybrid quantization of the linearly polarized Gowdy $T^3$ model with a massless scalar field with the same symmetries as the metric. For simplicity, we quantize its restriction to the model with local rotational symmetry. Using…

General Relativity and Quantum Cosmology · Physics 2013-03-05 Daniel Martín-de Blas , Mercedes Martín-Benito , Guillermo A. Mena Marugán

We develop a systematic classical framework to accommodate canonical quantization of geometric and matter perturbations on a quantum homogeneous isotropic flat spacetime. The existing approach of standard cosmological perturbations is…

General Relativity and Quantum Cosmology · Physics 2013-06-05 Andrea Dapor , Jerzy Lewandowski , Jacek Puchta
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