Big-Bounce cosmology in the presence of Immirzi field

TL;DR

This paper explores a loop quantum cosmology model with a dynamic Immirzi field, demonstrating how quantum effects can resolve the classical Big Bang singularity in a flat isotropic universe.

Contribution

It introduces a scalar Immirzi field into the Hamiltonian framework and applies a loop quantum cosmology approach to show singularity resolution.

Findings

Quantum effects remove the initial singularity

Immirzi field can serve as a relational time

Classical singularity is replaced by a quantum bounce

Abstract

The Immirzi parameter is promoted to be a scalar field and the Hamiltonian analysis of the corresponding dynamical system is performed in the presence of gravity. We identified some SU(2) connections, generalizing Ashtekar-Barbero variables, and we rewrite the constraints in terms of them, setting the classical formulation suitable for loop quantization. Then, we consider the reduced system obtained when restricting to a flat isotropic cosmological model. By mimicking loop quantization via an effective semiclassical treatment, we outline how quantum effects are able to tame the initial singularity both in synchronous time and when the Immirzi field is taken as a relational time.