Creating universes with thick walls

TL;DR

This paper investigates the dynamics of false vacuum bubbles with thick walls in scalar field theories, providing numerical solutions for quantum tunneling processes and challenging previous thin-wall approximations.

Contribution

It introduces numerical solutions for thick-wall vacuum bubbles and refutes the significance of zero mass solutions in the FGG tunneling process.

Findings

Lower bound on ADM mass is a significant fraction of scalar field mass

Zero mass solutions are artifacts of thin wall approximation

Thick wall analysis supports the physicality of FGG tunneling

Abstract

We study the dynamics of a spherically symmetric false vacuum bubble embedded in a true vacuum region separated by a "thick wall", which is generated by a scalar field in a quartic potential. We study the "Farhi-Guth-Guven" (FGG) quantum tunneling process by constructing numerical solutions relevant to this process. The ADM mass of the spacetime is calculated, and we show that there is a lower bound that is a significant fraction of the scalar field mass. We argue that the zero mass solutions used to by some to argue against the physicality of the FGG process are artifacts of the thin wall approximation used in earlier work. We argue that the zero mass solutions should not be used to question the viability of the FGG process.