Dynamics of quantum anisotropies in a Taub Universe in the WKB approximation

Abstract

We analyze the dynamics of a Taub cosmological model in the presence of a massless minimally coupled scalar field and a cosmological constant, in the limit when both the Universe volume and the scalar field live in a quasi-classical approximation. By other words, we study the dynamics of a quantum small anisotropy evolving on a de Sitter background and in the presence of a kinetic term of the inflaton field. We demonstrate that the quantum anisotropy exponentially decays during the Universe expansion, approaching a finite and small value. This result suggests that the quantum isotropization of the Universe during a de Sitter phase is much weaker than the corresponding classical evolution, favouring the survival of certain degree of anisotropy to the de Sitter phase. Finally we analyze the case when also the scalar field is considered as quantum variable, by showing how its variance naturally spreads because of no potential term significantly affects its dynamics. This behaviour results to be different from the anisotropy which is subjected to the potential coming out from the spatial curvature.

arXiv comment9 pages, 3 figures

References in corpus (5)

• Quantum Nature of the Big Bang
• Quantum-gravitational effects on gauge-invariant scalar and tensor perturbations during inflation: The de Sitter case
• On the cosmological singularity
• Semiclassical suppression of weak anisotropies of a generic Universe
• Probabilistic interpretation of the wave function for the Bianchi I model

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• A Scenario for a Singularity-free Generic Cosmological Solution
• On the emergence of a classical Isotropic Universe from a Quantum $f(R)$ Bianchi Cosmology in the Jordan Frame
• The role of spatial curvature in constraining the Universe anisotropies across a Big Bounce
• Quantum Gravity Corrections to the inflationary spectrum in a Bohmian approach
• Quantum Isotropic Universe in RQM Analogy: the Cosmological Horizon