Cosmic Hysteresis

TL;DR

This paper explores cosmological hysteresis in cyclic universe models, showing how thermodynamic asymmetries can lead to increasing cycle amplitudes and influence universe expansion dynamics.

Contribution

It introduces the concept of cosmological hysteresis in modified gravity models and analyzes its effects on the evolution of cyclic universe scenarios.

Findings

Hysteresis causes amplitude growth in universe cycles.

The sign of the integral of pdV influences expansion behavior.

Conditions for an ever-expanding universe depend on model parameters.

Abstract

Cosmological hysteresis, has interesting and vivid implications in the scenario of a cyclic bouncy universe. This, purely thermodynamical in nature, is caused by the asymmetry in the equation of state parameter during expansion and contraction phase of the universe, due to the presence of a single scalar field. When applied to variants of modified gravity models this phenomenon leads to the increase in amplitude of the consecutive cycles of the universe, provided we have physical mechanisms to make the universe bounce and turnaround. This also shows that the conditions which creates a universe with an ever increasing expansion, depend on the signature of $\oint pdV$ and on model parameters.