Gravitational waves from the sound shell model: direct and inverse phase transitions in the early Universe

Barni, Giulio; Vanvlasselaer, Miguel; Madge, Eric; Blasi, Simone

Preprint

PUBDB-2025-04531

Gravitational waves from the sound shell model: direct and inverse phase transitions in the early Universe

Barni, G. ; Blasi, S.DESY* ; Madge, E. (Corresponding author) ; Vanvlasselaer, M.

2026

This record in other databases:

Report No.: DESY-25-144; IFT-UAM/CSIC-25-118; arXiv:2510.21439

Abstract: Cosmological first order phase transitions are a frequent phenomenon in particle physics beyond the Standard Model, and the corresponding gravitational wave signal offers a key probe of new physics in the early Universe. Depending on the underlying microphysics, the transition can exhibit either direct or inverse hydrodynamics, leading to a different phenomenology. Most studies to date have focused on direct transitions, where the cosmic fluid is pushed or dragged by the expanding vacuum bubbles. In contrast, inverse phase transitions are characterized by fluid profiles where the plasma is sucked in by the expanding bubbles.Using the sound shell model, we derive and compare the gravitational wave spectra from sound waves for direct and inverse phase transitions, providing new insights into the potential observable features and the possibility of discriminating among the various fluid solutions in gravitational wave experiments.

Keyword(s): cosmological phase transitions ; gravitational waves / sources ; primordial gravitational waves (theory)

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