Curvature Perturbations from First-Order Phase Transitions: Implications to Black Holes and Gravitational Waves

Abstract

Understanding whether primordial black holes form during strong first-order phase transition (FOPT) is a crucial open question in cosmology. We address this using a fully covariant formalism to study cosmological perturbations, highlighting previously overlooked gauge dependencies. We show that non-covariant treatments can overestimate primordial black holes and scalar-induced gravitational waves. Once gauge dependencies are accounted for, both signals are strongly suppressed, with direct implications for the FOPT interpretation of the Pulsar Timing Array signal.

Published in PRL (5 pages, 4 figures). Promised companion paper added as Supplemental Material (14 pages, 6 figures). Results reproducible with public code: https://github.com/YannGou/deltaPT2.0

References in corpus (1)

• Implications for Pulsar Timing Arrays of Sub-solar Black Hole Detections: From LVK to Einstein Telescope and Cosmic Explorer

Cited by in corpus (6)

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• Numerical simulations of primordial black hole formation via delayed first-order phase transitions
• Hard thermal contributions to phase transition observables at NNLO
• Investigating a strong first-order electroweak phase transition in the RxSM at future linear $e^{+}{e}^{-}$ colliders and LISA
• The Dark Side of the Moon: Listening to Scalar-Induced Gravitational Waves