Quasiclassical model of inhomogeneous cosmology

TL;DR

This paper extends static quasiclassical space-time models to dynamical ones, showing that quantum fluctuations in both metric components are essential for maintaining general covariance in early-universe cosmology.

Contribution

It introduces a dynamical quasiclassical model of inhomogeneous cosmology with two metric components, emphasizing the importance of individual quantum moments for covariance.

Findings

Quantum fluctuations in both metric components are necessary for covariance.

Quantum correlations between components are less critical.

The model describes the evolution of 1D space with quantum corrections.

Abstract

Fluctuation terms and higher moments of a quantum state imply corrections to the classical equations of motion that may have implications in early-universe cosmology, for instance in the state-dependent form of effective potentials. In addition, space-time properties are relevant in cosmology, in particular when combined with quantum corrections required to maintain general covariance in a consistent way. Here, an extension of previous investigations of static quasiclassical space-time models to dynamical ones is presented, describing the evolution of 1-dimensional space as in the classical Lemaitre--Tolman--Bondi models. The corresponding spatial metric has two independent components, both of which are in general subject to quantum fluctuations. The main result is that individual moments from both components are indeed required for general covariance to be maintained at a semiclassical level, while quantum correlations between the components are less relevant.