Sound velocity effects on the phase transition gravitational wave spectrum in the sound shell model

TL;DR

This paper investigates how variations in sound velocities during a cosmological first-order phase transition affect the gravitational wave spectrum, emphasizing the importance of realistic sound velocity values for accurate predictions.

Contribution

It introduces the effect of different sound velocities in symmetric and broken phases on gravitational wave spectra within the sound shell model, enhancing prediction accuracy.

Findings

Different sound velocities significantly alter peak frequency and amplitude.

Realistic sound velocities are crucial for precise gravitational wave predictions.

The study improves understanding of acoustic gravitational wave signals from phase transitions.

Abstract

A cosmological first-order phase transition gravitational wave could provide a novel approach to studying the early Universe. In most cases, the acoustic gravitational wave from the sound wave mechanism is dominant. Considering different sound velocities in symmetric and broken phases, we study sound velocity effects on the acoustic phase transition gravitational wave spectra in the sound shell model. We demonstrate that different sound velocities could obviously modify the peak frequency and peak amplitude of the gravitational wave power spectra. Therefore, taking more realistic sound velocities might provide more accurate predictions for various gravitational wave experiments.