Cosmological phase transitions: from particle physics to gravitational waves, semi-analytically

TL;DR

This paper presents a semi-analytical method to predict gravitational wave spectra from supercooled first order phase transitions in the early universe, enabling efficient exploration of particle physics models and their cosmological signatures.

Contribution

It introduces a semi-analytical pipeline for calculating gravitational wave spectra from cosmological phase transitions, reducing reliance on computationally intensive simulations.

Findings

Accurate semi-analytical predictions of gravitational wave spectra.

Efficient exploration of particle physics models beyond the Standard Model.

Potential to interpret gravitational wave signals in terms of early universe physics.

Abstract

Motivated by the recent evidence of a stochastic gravitational wave background found by pulsar timing array experiments, we focus on one of the prime cosmological explanations, i.e. a supercooled first order phase transition. If confirmed, it would offer a unique opportunity to probe early Universe dynamics and the related physics beyond the Standard Model of particles and interactions. However, the prediction of the gravitational wave spectrum from a given particle physics scenario requires theoretically and computationally demanding methods. While several tools have been put forward to reduce uncertainties and automatize these computations, we study here the possibility to perform the full pipeline of computations semi-analytically in the $4D$ theory, thus avoiding computationally intensive simulations. Our approach yields accurate results that can be used in phenomenological studies and allow for an efficient exploration of the connection between the particle physics models and their cosmological predictions.