Dynamics of Metastable Vacua in the Early Universe

TL;DR

This paper investigates whether metastable vacua are populated during early universe phase transitions, using numerical simulations of a Langevin equation with a Standard Model-inspired potential and non-renormalizable operators, revealing dependence on model parameters.

Contribution

It introduces a numerical approach to study metastable vacuum population in early universe phase transitions considering non-renormalizable operators and temperature effects.

Findings

Metastable vacuum population depends on the parameter eta for small scalar couplings.

For large scalar couplings, the system always ends in the metastable minimum.

The model incorporates finite temperature effects and non-renormalizable operators.

Abstract

We study the question whether a possible metastable vacuum state is actually populated in a phase transition in the early universe, as is usually assumed in the discussion of vacuum stability bounds e.g. for Standard Model parameters. A phenomenological (3+1)-dimensional Langevin equation is solved numerically for a toy model with a potential motivated by the finite temperature 1-loop effective potential of the Standard Model including additional non-renormalizable operators from an effective theory for physics beyond the Standard Model and a time dependent temperature. It turns out that whether the metastable vacuum is populated depends critically on the value of the phenomenological parameter eta for small scalar couplings. For large enough scalar couplings and with our specific form of the non-renormalizable operators the system (governed by the Langevin equation) always ends up in the metastable minimum.