Phenomenological dynamics of loop quantum cosmology in Kantowski-Sachs spacetime

TL;DR

This paper explores how loop quantum cosmology modifies Kantowski-Sachs spacetime, resolving classical singularities into quantum bounces through phenomenological dynamics with two quantization schemes.

Contribution

It extends loop quantum cosmology to anisotropic and curved Kantowski-Sachs spacetime, demonstrating singularity resolution via quantum bounces in two quantization schemes.

Findings

Classical singularities replaced by quantum bounces.

Bouncing scenarios analogous to Bianchi I model.

Symmetries suggest a link between spatial and temporal scales.

Abstract

The fundamental theory and the semiclassical description of loop quantum cosmology (LQC) have been studied in the Friedmann-Robertson-Walker and Bianchi I models. As an extension to include both anisotropy and intrinsic curvature, this paper investigates the cosmological model of Kantowski-Sachs spacetime with a free massless scalar field at the level of phenomenological dynamics with the LQC discreteness corrections. The LQC corrections are implemented in two different improved quantization schemes. In both schemes, the big bang and big crunch singularities of the classical solution are resolved and replaced by the big bounces when the area or volume scale factor approaches the critical values in the Planck regime measured by the reference of the scalar field momentum. Symmetries of scaling are also noted and suggest that the fundamental spatial scale (area gap) may give rise to a temporal scale. The bouncing scenarios are in an analogous fashion of the Bianchi I model, naturally extending the observations obtained previously.