Crunch from AdS bubble collapse in unbounded potentials

TL;DR

This paper demonstrates that in a scalar field theory with an unbounded potential, an AdS bubble embedded in flat spacetime typically collapses into a space-like singularity before reaching the true vacuum, regardless of potential bounds.

Contribution

It provides evidence that AdS bubbles in unbounded potentials undergo inevitable collapse into singularities, expanding understanding of vacuum decay and bubble dynamics in such theories.

Findings

AdS bubbles with zero total energy collapse into singularities.

Collapse occurs before the true vacuum is reached.

Lower bounds on the potential are not necessary for collapse.

Abstract

We consider a scalar field theory with a Minkowski false vacuum and an unbounded (or very deep) true vacuum. We show compelling evidence that an AdS bubble of vanishing total energy, embedded in asymptotically flat spacetime, generically undergoes a spherical collapse which leads to a space-like curvature singularity after the formation of trapped surfaces and apparent horizons. The crunch singularity, which is hided behind an apparent horizon, occurs before the true vacuum is reached, and the existence of a lower bound of the scalar field potential is not a necessary condition for its formation.