Quantum Fluctuations and New Instantons II: Quartic Unbounded Potential

TL;DR

This paper investigates false vacuum decay in a quartic unbounded potential, demonstrating the existence of regularized instantons that facilitate vacuum decay without traditional Coleman instantons.

Contribution

It introduces a new class of regularized instantons for unbounded quartic potentials, expanding understanding of vacuum decay mechanisms beyond classical solutions.

Findings

Regularized instantons exist where Coleman instantons do not.

Quantum fluctuations can regularize singular classical solutions.

Derived decay rates for the new instantons.

Abstract

We study the fate of a false vacuum in the case of a potential that contains a portion which is quartic and unbounded. We first prove that an $O(4)$ invariant instanton with the Coleman boundary conditions does not exist in this case. This, however, does not imply that the false vacuum does not decay. We show how the quantum fluctuations may regularize the singular classical solutions. This gives rise to a new class of $O(4)$ invariant regularized instantons which describe the vacuum instability in the absence of the Coleman instanton. We derive the corresponding solutions and calculate the decay rate they induce.