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

Understand

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.