Inclusion of matter in inhomogeneous loop quantum cosmology

TL;DR

This paper develops a hybrid loop quantum cosmology model for inhomogeneous Gowdy $T^3$ universes with a scalar field, demonstrating singularity resolution and enabling the study of inhomogeneity back-reaction on quantum cosmological backgrounds.

Contribution

It introduces a hybrid quantization approach combining loop and Fock methods for inhomogeneous cosmologies with matter, extending previous models to include matter fields.

Findings

Resolution of cosmological singularity in the model

Modeling of inhomogeneities propagating in quantum cosmological backgrounds

Framework for studying quantum back-reaction effects

Abstract

We study the hybrid quantization of the linearly polarized Gowdy $T^3$ model with a massless scalar field with the same symmetries as the metric. For simplicity, we quantize its restriction to the model with local rotational symmetry. Using this hybrid approach, the homogeneous degrees of freedom of the geometry are quantized \`a la loop, leading to the resolution of the cosmological singularity. A Fock quantization is employed both for the matter and the gravitational inhomogeneities. Owing to the inclusion of the massless scalar field this system allows us to modelize flat Friedmann-Robertson-Walker cosmologies filled with inhomogeneities propagating in one direction, providing a perfect scenario to study the quantum back-reaction of the inhomogeneities on the polymeric homogeneous and isotropic background.