On the Cosmological Stability of the Higgs Instability

TL;DR

This paper investigates the stability of the Higgs potential during cosmological inflation, suggesting that Higgs instabilities might not threaten our universe and could even aid in ending inflation and reheating.

Contribution

It introduces a novel cosmological perspective on Higgs instability, proposing that collapsing Higgs bubbles could be harmless and facilitate universe reheating.

Findings

Higgs bubbles may collapse harmlessly due to backreaction.

Higgs instability could provide a mechanism to end inflation.

The bound on the Hubble rate during inflation may be relaxed.

Abstract

The Standard Model Higgs potential becomes unstable at large Higgs field values where its quartic coupling becomes negative. While the tunneling lifetime of our current electroweak vacuum is comfortably longer than the age of the universe, quantum fluctuations during inflation might push the Higgs over the barrier, forming patches which might be lethal for our universe. We study the cosmological evolution of such regions and find that, at least in the thin wall approximation, they may be harmless as they collapse due to the backreaction of the Higgs itself. The presence of the Standard Model Higgs instability can provide a novel mechanism to end inflation and to reheat the universe through the evaporation of the black holes left over by the collapse of the Higgs bubbles. The bound on the Hubble rate during inflation may be therefore relaxed.