Entanglement production through a cosmological bounce

TL;DR

This paper investigates how matter-gravity entanglement evolves during a cosmological bounce, revealing entropy dynamics that challenge the notion of a Second Law in quantum cosmology.

Contribution

It demonstrates that matter-gravity entanglement entropy behaves non-monotonically during a bounce, providing new insights into quantum cosmological models with Gaussian initial states.

Findings

Entanglement entropy rises rapidly during the bounce.

Entropy declines and approaches a steady-state post-bounce.

No evidence of a Second Law of entanglement entropy in this scenario.

Abstract

In quantum cosmology, it is expected that the Big Bang singularity is resolved and the universe undergoes a bounce. We find that for Gaussian initial states, matter-gravity entanglement entropy rises rapidly during the bounce, declines, and then approaches a steady-state value following the bounce. These observations suggest that matter-gravity entanglement is a feature of the macroscopic universe and that there is no Second Law of entanglement entropy.