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Cosmic inflation may exhibit stochastic periods during which quantum fluctuations dominate over the semi-classical evolution. Extracting observables in these regimes is a notoriously difficult program as quantum randomness makes them fully…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-27 Baptiste Blachier , Christophe Ringeval

We investigate the $\phi^2$ inflationary model in the Bianchi-I spacetime using effective spacetime description of loop quantum cosmology to understand the issues of the resolution of initial singularity, isotropization, effect of…

General Relativity and Quantum Cosmology · Physics 2013-07-11 Brajesh Gupt , Parampreet Singh

We consider the measure problem in standard slow-roll inflationary models from the perspective of loop quantum cosmology (LQC). Following recent results by Ashtekar and Sloan, we study the probability of having enough e-foldings and focus…

General Relativity and Quantum Cosmology · Physics 2011-05-12 Alejandro Corichi , Asieh Karami

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

In this article we explore the pre-inflationary background dynamics of an FLRW universe sourced by a scalar field with monodromy potential in LQC framework. In particular we calculate the number of e-folds, $N_{inf}$, produced during the…

General Relativity and Quantum Cosmology · Physics 2018-11-15 Manabendra Sharma , M. Shahalam , Wu Qiang , Anzhong Wang

Loop quantum cosmology(LQC) is the symmetric model of loop quantum gravity. In this paper, we generalize the structure of loop quantum cosmology to the theories with arbitrary spacetime dimensions. The isotropic and homogenous cosmological…

General Relativity and Quantum Cosmology · Physics 2016-10-13 Xiangdong Zhang

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 consider a classical field in square torsion theory as a source of torsion for a quantum fermion field in FLRW metric. In the framework of QFT, we obtain vacuum contributions to the energy-momentum tensor and to the axial current that…

High Energy Physics - Theory · Physics 2026-03-20 Antonio Capolupo , Sante Carloni , Luca Fabbri , Simone Monda , Aniello Quaranta , Stefano Vignolo

It is often argued that inflation erases all the information about what took place before it started. Quantum gravity, relevant in the Planck era, seems therefore mostly impossible to probe with cosmological observations. In general, only…

General Relativity and Quantum Cosmology · Physics 2016-06-15 Boris Bolliet , Aurelien Barrau , Julien Grain , Susanne Schander

This paper focuses on the search for a coherent and consistent formulation to describe quantum gravity corrections to Quantum Field Theory. We implement two fundamental ingredients discussed in previous analyses: on one hand, the…

General Relativity and Quantum Cosmology · Physics 2024-10-15 Giulia Maniccia , Giovanni Montani , Marco Tosoni

This work pioneers the quantization of primordial fermion perturbations in hybrid Loop Quantum Cosmology (LQC). We consider a Dirac field coupled to a spatially flat, homogeneous, and isotropic cosmology, sourced by a scalar inflaton, and…

General Relativity and Quantum Cosmology · Physics 2017-09-08 Beatriz Elizaga Navascués , Mercedes Martín-Benito , Guillermo A. Mena Marugán

We study the power spectrum of super-Hubble fluctuations of an inflaton-like scalar field, the "system", coupled to another scalar field, the "environment" during de Sitter inflation. We obtain the reduced density matrix for the inflaton…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-29 D. Boyanovsky

In this paper we study a massless, minimally coupled scalar field in a FLRW spacetime with periods of different constant deceleration parameter. We assume the Bunch-Davies vacuum during inflation and then use a sudden matching approximation…

General Relativity and Quantum Cosmology · Physics 2014-01-29 Drazen Glavan , Tomislav Prokopec , Vasileios Prymidis

We investigate the pre-inflationary dynamics of inflation with the Starobinsky potential, favored by recent data from the Planck mission, using techniques developed to study cosmological perturbations on quantum spacetimes in the framework…

General Relativity and Quantum Cosmology · Physics 2016-03-23 Béatrice Bonga , Brajesh Gupt

Non-perturbative quantum geometric effects in Loop Quantum Cosmology predict a $\rho^2$ modification to the Friedmann equation at high energies. The quadratic term is negative definite and can lead to generic bounces when the matter energy…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Parampreet Singh , Kevin Vandersloot , G. V. Vereshchagin

We use Dirac's method for the quantization of constrained systems in order to quantize a spatially flat Friedmann-Lema\^{i}tre-Robertson-Walker spacetime in the context of $f(Q)$ cosmology. When the coincident gauge is considered, the…

General Relativity and Quantum Cosmology · Physics 2021-10-22 N. Dimakis , A. Paliathanasis , T. Christodoulakis

Warm inflation is analyzed in the context of Loop Quantum Cosmology (LQC). The bounce in LQC provides a mean through which a Liouville measure can be defined, which has been used previously to characterize the a priori probability for…

General Relativity and Quantum Cosmology · Physics 2018-08-01 L. L. Graef , Rudnei O. Ramos

As a contribution to a viable candidate for a standard model of cosmology, we here show that pre-inflationary quantum fluctuations can provide a scenario for the long-sought initial conditions for the inflaton field. Our proposal is based…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-09 I. G. Marian , N. Defenu , U. D. Jentschura , A. Trombettoni , I. Nandori

Unifying the early-universe inflationary paradigm with late-time cosmic acceleration, while resolving the initial Big Bang singularity, remains one of the most profound challenges in modern cosmology. In this paper, we propose a…

General Relativity and Quantum Cosmology · Physics 2026-05-20 Zhiming Shuai , Xiangdong Zhang

We systematically study the preinflationary dynamics of the spatially flat Friedmann-Lemaitre-Robertson-Walker universe filled with a single scalar field that has the generalized $\alpha-$attractor potentials, in the framework of loop…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-29 M. Shahalam , M. Sami , Anzhong Wang
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