Cosmology with quantum matter and a classical gravitational field

TL;DR

This paper explores a hybrid cosmological model combining classical gravity with a quantized scalar field, using an ensemble formalism as an alternative to semiclassical gravity, and discusses a solution similar to the Einstein universe.

Contribution

It introduces a novel hybrid approach to cosmology with classical and quantum fields using ensembles on configuration space, providing new insights beyond traditional semiclassical methods.

Findings

Develops a formalism for classical-quantum interaction in spherically symmetric gravity.

Proposes a specific solution analogous to the Einstein universe.

Offers an alternative framework to semiclassical gravity for cosmological models.

Abstract

I consider a hybrid cosmological model with a classical gravitational field and a quantized massive scalar field in spherically symmetric gravity. The interaction between classical and quantum fields is described using the formalism of ensembles on configuration space, an approach that provides an alternative to semiclassical gravity. After giving an outline of the formulation as it applies to spherically symmetric gravity, I discuss a particular solution that is analogous to the Einstein universe of classical relativity.