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We investigate quantum cosmological models in an n-dimensional anisotropic universe in the presence of a massless scalar field. Our basic inspiration comes from Chodos and Detweiler's classical model which predicts an interesting behaviour…

General Relativity and Quantum Cosmology · Physics 2018-02-14 F. A. P. Alves-Júnior , M. L. Pucheu , A. B. Barreto , C. Romero

The use of quantum field theory to understand astrophysical phenomena is not new. However, for the most part, the methods used are those that have been developed decades ago. The intervening years have seen some remarkable developments in…

High Energy Astrophysical Phenomena · Physics 2019-11-11 Daniel J. Burger , Raúl Carballo-Rubio , Nathan Moynihan , Jeff Murugan , Amanda Weltman

We introduce the notion of background independent quantum field theory. The distinguishing feature of this theory is that the dynamics can be formulated without recourse to a background metric structure. We show in a simple model how the…

High Energy Physics - Theory · Physics 2007-05-23 Olaf Dreyer

Assuming the existence of a scalar field which undergoes "ghost condensation" and which has a suitably chosen potential, it is possible to obtain a non-singular bouncing cosmology in the presence of regular matter and radiation. The…

High Energy Physics - Theory · Physics 2011-04-20 Chunshan Lin , Robert H. Brandenberger , Laurence Perreault Levasseur

The cosmological constant problem can be understood as the failure of the decoupling principle behind effective field theory, so that some quantities in the low-energy theory are extremely sensitive to the high-energy properties. While this…

High Energy Physics - Theory · Physics 2015-12-01 Carlos Barceló , Raúl Carballo-Rubio , Luis J. Garay

The use of techniques from loop quantum gravity for cosmological models may solve some difficult problems in quantum cosmology. The solutions under a number of circumstances have been well studied. We will analyse the behaviour of solutions…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Daniel Green , William G. Unruh

Inflationary cosmology has, in the last few years,received a strong dose of support from observations. The fact that the fluctuation spectrum can be extracted from the inflationary scenario through an analysis that involves quantum field…

General Relativity and Quantum Cosmology · Physics 2009-07-24 Daniel Sudarsky , Adolfo De Unanue

We study the impact of effective interactions onto relationally evolving GFT condensates based on real-valued fields. In a first step we show that a free condensate configuration in an isotropic restriction settles dynamically into a…

General Relativity and Quantum Cosmology · Physics 2017-03-08 Andreas G. A. Pithis , M. Sakellariadou

Cosmological models arising from a generalized compactification of Einstein gravity are derived. It is shown that a redefinition of the moduli fields reduces the system to a set of massless fields and a single field with a single…

Astrophysics · Physics 2009-10-31 Anne M. Green , James E. Lidsey

We review recent literature on the connection between quantum entanglement and cosmology, with an emphasis on the context of expanding universes. We discuss recent theoretical results reporting on the production of entanglement in quantum…

General Relativity and Quantum Cosmology · Physics 2015-03-20 Eduardo Martin-Martinez , Nicolas C. Menicucci

We discuss the cosmological constant problem in the light of dilatation symmetry and its possible anomaly. For dilatation symmetric quantum theories realistic asymptotic cosmology is obtained provided the effective potential has a…

High Energy Physics - Theory · Physics 2017-11-13 C. Wetterich

We study the cosmological evolution of the field equations in the context of Einstein-Aether cosmology by including a scalar field in a spatially flat Friedmann--Lema\^{\i}tre--Robertson--Walker spacetime. Our analysis is separated into two…

General Relativity and Quantum Cosmology · Physics 2020-01-17 Andronikos Paliathanasis , G. Papagiannopoulos , Spyros Basilakos , John D. Barrow

We study the cosmological sector of the Lorentzian Barrett-Crane (BC) model coupled to a free massless scalar field in its Group Field Theory (GFT) formulation, corresponding to the mean-field hydrodynamics obtained from coherent condensate…

General Relativity and Quantum Cosmology · Physics 2022-01-31 Alexander F. Jercher , Daniele Oriti , Andreas G. A. Pithis

It has long been a primary objective of cosmology to understand the apparent isotropy in our universe and to provide a mathematical formulation for its evolution. A school of thought for its explanation is quiescent cosmology, which already…

General Relativity and Quantum Cosmology · Physics 2010-01-19 Philipp A Hoehn , Susan M Scott

We revisit here the problem of generalized cosmology using renormalization group approach. A complete analysis of these cosmologies, where specific models appear as asymptotic fixed-points, is given here along with their linearized…

General Relativity and Quantum Cosmology · Physics 2008-11-26 J. Ibanez , S. Jhingan

A theory of gravitation is constructed in which all homogeneous and isotropic solutions are nonsingular, and in which all curvature invariants are bounded. All solutions for which curvature invariants approach their limiting values approach…

General Relativity and Quantum Cosmology · Physics 2009-10-22 R. Brandenberger , V. Mukhanov , A. Sornborger

In this paper, we study a triad of inhomogeneous scalar fields, known as "solid", as a source of homogeneous but anisotropic dark energy. By using a dynamical system approach, we find that anisotropic accelerated solutions can be realized…

General Relativity and Quantum Cosmology · Physics 2021-04-22 J. Motoa-Manzano , J. Bayron Orjuela-Quintana , Thiago S. Pereira , César A. Valenzuela-Toledo

Corrections are computed to the classical static isotropic solution of general relativity, arising from non-perturbative quantum gravity effects. A slow rise of the effective gravitational coupling with distance is shown to involve a…

High Energy Physics - Theory · Physics 2008-11-26 Herbert W. Hamber , Ruth M. Williams

In this paper we construct a model for group field cosmology. The classical equations of motion for the non-interactive part of this model generate the Hamiltonian constraint of loop quantum gravity for a homogeneous isotropic universe…

General Relativity and Quantum Cosmology · Physics 2015-06-11 Mir Faizal

The last decades have witnessed an unprecedented advancement in our knowledge of the large scale universe. In particular, increasingly accurate cosmological observations have allowed us to discover a form of "dark energy", which presently…

General Relativity and Quantum Cosmology · Physics 2022-04-11 Eduardo Amancio Barbosa Oliveira