Vacuum bubbles from cosmic ripples
arXiv:2604.01516 · doi:10.1007/JHEP07(2026)263
The paper studies how density perturbations in the early Universe affect vacuum decay, showing that over‑densities can accelerate bubble nucleation while under‑densities suppress it, using both thin‑wall analytic estimates and numerical bounce solutions.
Abstract
We investigate vacuum decays in the early Universe in the presence of curvature perturbations. For sufficiently large perturbations associated with over-densities, we find that the bounce solution develops an oscillating middle stage near the bubble wall. For small perturbations, we analytically show within the thin-wall approximation that an over- (under-) density would enhance (suppress) the vacuum decay rate with a smaller (larger) initial bubble radius. By numerically solving for the bounce solutions and evaluating the corresponding Euclidean action, we further confirm this behaviour in thick-wall cases. Our results indicate that over-densities can generically trigger vacuum decay at an earlier moment.
20 pages, 4 figures, Accepted by JHEP