Higgs vacuum metastability in primordial inflation, preheating, and reheating

TL;DR

This paper examines the stability of the Higgs vacuum during cosmic inflation, preheating, and reheating, highlighting the challenges posed by quantum and thermal fluctuations at high energy scales and proposing mechanisms to mitigate these effects.

Contribution

It analyzes Higgs vacuum stability across different early universe stages and evaluates the effectiveness of nonminimal couplings in preventing destabilization at high inflation scales.

Findings

Higgs vacuum destabilization is likely at GUT-scale inflation without protective couplings.

Nonminimal Higgs-gravity or inflaton-Higgs couplings can suppress vacuum fluctuations during inflation.

Vacuum stability requires the inflation energy scale to be well below the GUT scale.

Abstract

Current measurements of the Higgs boson mass and top Yukawa coupling suggest that the effective Higgs potential develops an instability below the Planck scale. If the energy scale of inflation is as high as the GUT scale, inflationary quantum fluctuations of the Higgs field can easily destabilize the standard electroweak vacuum and produce a lot of AdS domains. This destabilization during inflation can be avoided if a relatively large nonminimal Higgs-gravity or inflaton-Higgs coupling is introduced. Such couplings generate a large effective mass term for the Higgs, which can raise the effective Higgs potential and suppress the vacuum fluctuation of the Higgs field. After primordial inflation, however, such effective masses drops rapidly and the nonminimal Higgs-gravity or inflaton-Higgs coupling can cause large fluctuations of the Higgs field to be generated via parametric resonance, thus producing AdS domains in the preheating stage. Furthermore, thermal fluctuations of the Higgs field cannot be neglected in the proceeding reheating epoch. We discuss the Higgs vacuum fluctuations during inflation, preheating, and reheating, and show that the Higgs metastability problem is severe unless the energy scale of the inflaton potential is much lower than the GUT scale.