Spacetime Dynamics of a Higgs Vacuum Instability During Inflation

TL;DR

This paper investigates how Higgs vacuum instability during inflation can lead to black hole formation and explores the implications for the stability of our universe, using numerical simulations and probabilistic modeling.

Contribution

It provides a detailed numerical analysis of Higgs fluctuations during inflation and establishes a link between observable cosmological parameters and Higgs potential stability.

Findings

Formation of true vacuum patches leads to black holes incompatible with our universe

Black hole horizons can become highly elongated, violating the hoop conjecture

A correlation between tensor-to-scalar ratio and Higgs potential stabilization scale

Abstract

A remarkable prediction of the Standard Model is that, in the absence of corrections lifting the energy density, the Higgs potential becomes negative at large field values. If the Higgs field samples this part of the potential during inflation, the negative energy density may locally destabilize the spacetime. We use numerical simulations of the Einstein equations to study the evolution of inflation-induced Higgs fluctuations as they grow towards the true (negative-energy) minimum. These simulations show that forming a single patch of true vacuum in our past light cone during inflation is incompatible with the existence of our Universe; the boundary of the true vacuum region grows outward in a causally disconnected manner from the crunching interior, which forms a black hole. We also find that these black hole horizons may be arbitrarily elongated---even forming black strings---in violation of the hoop conjecture. By extending the numerical solution of the Fokker-Planck equation to the exponentially suppressed tails of the field distribution at large field values, we derive a rigorous correlation between a future measurement of the tensor-to-scalar ratio and the scale at which the Higgs potential must receive stabilizing corrections in order for the Universe to have survived inflation until today.