Speaker
Antonino Salvino Midiri
(Universite de Geneve (CH))
Description
We study the irrotational velocity spectra induced in a fluid during a first-order phase transition in the radiation-dominated era. Interactions of the scalar broken-phase bubbles with the fluid generate irrotational velocity and enthalpy profiles which are, together with the statistical time distribution of bubble nucleation and collision, predictive of the gravitational wave spectrum produced in the sound-wave phase after bubble collisions. The main result we present is a refined template for the spectrum of the initial fluid perturbations in the acoustic phase in terms of phase transition parameters, showing how its amplitude and spectral shape can be reconstructed from the scales that appear in the single-bubble perturbations.
