Physical Aspects of Unitary evolution of Bianchi-I Quantum Cosmological Model

TL;DR

This paper investigates the unitary evolution of the Bianchi-I quantum cosmological model, analyzing volume behavior, anisotropy, and wavefunction interpretations for different fluid parameters, revealing non-singular evolution and potential phase transitions.

Contribution

It provides a detailed analysis of the physical aspects of unitary evolution in Bianchi-I quantum cosmology, including wavefunction interpretations and phase transition phenomena for various fluid parameters.

Findings

Expectation value of volume avoids singularity

Wavefunction as superposition of collapsing and expanding universes

Possible phase transition for different fluid parameters

Abstract

In this work, we study some physical aspects of unitary evolution of Bianchi-I model. In particular, we study the behavior of the volume and the scale factor as a function of time for the Bianchi-I universe with ultra-relativistic fluid ($\alpha=1$). The expectation value of volume is shown not to hit any singularity. We elucidate on the anisotropic nature of the solution and physically interpret the wavefunction as a superposition of collapsing universe and expanding universe mimicking Hartle-Hawking type wavefunction. The same analysis has been done for $\alpha\neq 1$ as well. The work also comments on how to obtain Vilenkin type wavefunction representing an expanding universe without that being superposed with a solution representing a collapsing universe. We also point at a possible phase transition phenomenon for $\alpha\neq1$ case with existence of a critical parameter.