Detectability of Gravitational Waves from Phase Transitions

TL;DR

This paper explores the potential for detecting gravitational waves generated by early universe phase transitions, providing semi-analytic spectra models and identifying detectable parameter regions for future observatories.

Contribution

It introduces semi-analytic models for gravitational wave spectra from early universe phase transitions and assesses their detectability with upcoming gravitational wave detectors.

Findings

Electroweak phase transition signals are detectable over a wide parameter range.

Semi-analytic expressions for gravitational wave spectra from various sources are provided.

Detection prospects depend on phase transition properties and detector sensitivities.

Abstract

Gravitational waves potentially represent our only direct probe of the universe when it was less than one second old. In particular, first-order phase transitions in the early universe can generate a stochastic background of gravitational waves which may be detectable today. We briefly summarize the physical sources of gravitational radiation from phase transitions and present semi-analytic expressions for the resulting gravitational wave spectra from three distinct realistic sources: bubble collisions, turbulent plasma motions, and inverse-cascade helical magnetohydrodynamic turbulence. Using phenomenological parameters to describe phase transition properties, we determine the region of parameter space for which gravitational waves can be detected by the proposed Laser Interferometer Space Antenna. The electroweak phase transition is detectable for a wide range of parameters.