How large are curvature perturbations from slow first-order phase transitions? A gauge-invariant analysis
Abstract
When strongly supercooled cosmological first-order phase transitions (FOPTs) are sufficiently slow, super-horizon inhomogeneities can be generated. We compute these super-horizon curvature perturbations by employing a gauge-invariant, multi-fluid formalism. By resolving the gauge ambiguities inherent in conventional separate-universe simulations, we demonstrate that Primordial Black Holes are unlikely to be produced by these super-horizon inhomogeneities. We also derive a fitting formula for the resulting curvature perturbations and discuss potential observational constraints on FOPTs imposed by limits on primordial curvature perturbations and associated scalar-induced gravitational waves.
Keywords
Cite
@article{arxiv.2601.14412,
title = {How large are curvature perturbations from slow first-order phase transitions? A gauge-invariant analysis},
author = {Xiao Wang and Csaba Balázs and Ran Ding and Chi Tian},
journal= {arXiv preprint arXiv:2601.14412},
year = {2026}
}
Comments
10 pages, 6 figures and 1 table. Comments are welcome