Document Type

Article

Publication Date

4-15-2020

Abstract

Difference in pressure during expansion and contraction stages of the cosmic evolution can result in a hysteresislike phenomenon in nonsingular cyclic models sourced with a massive scalar field. We discuss this phenomenon for spatially closed isotropic spacetimes in loop quantum cosmology (LQC) for a quadratic and a coshlike potential, with and without a negative cosmological constant using an effective spacetime description of the underlying quantum geometry. Two inequivalent loop quantizations are investigated-one based on holonomies of the Ashtekar-Barbero connection using closed loops, and another based on the connection operator. Due to the underlying quantum geometric effects, both of the models avoid classical singularities, but unlike the holonomy based quantization, the connection based quantization results in two quantum bounces. In spite of the differences in nonsingular effective dynamics of both of the models, the phenomena of hysteresis is found to be robust for the φ2 potential. Quasiperiodic beats exist for the coshlike potential, irrespective of the nature of the classical recollapse whether by the spatial curvature, or a negative cosmological constant. An interplay of the negative cosmological constant and the spatial curvature in the presence of potentials results in rich features such as islands of cluster of bounces separated by an accelerated expansion and a universe which either undergoes a steplike expansion with multiple turnarounds or quasiperiodic beats depending on a "tuning" of the steepness parameter of the potential.

Publication Source (Journal or Book title)

Physical Review D

Download

Share

COinS