Collapse of simple harmonic universe

TL;DR

This paper demonstrates that certain classically stable oscillating and static universe models are quantum-mechanically unstable and can undergo collapse via tunneling, also providing instanton solutions for universe nucleation from nothing.

Contribution

It reveals the quantum instability of previously stable universe models and introduces instanton solutions for universe nucleation from nothing.

Findings

Classically stable universes are quantum-mechanically unstable.

Universes can collapse through quantum tunneling.

Instantons describe universe nucleation from nothing.

Abstract

In a recent paper Graham et al constructed oscillating and static universe models which are stable with respect to all classical perturbations. Here we show that such universes are quantum-mechanically unstable and can collapse by quantum tunneling to zero radius. We also present instantons describing nucleation of oscillating and static universes from nothing.