Speaker
Description
Cosmological first-order phase transitions may have generated a gravitational wave background detectable by LISA, offering a unique window into physics beyond the Standard Model. A crucial step in predicting this background is the reliable computation of bubble nucleation rates. In this talk, we overview the current state of perturbative calculations based on effective field theories and Boltzmann equations. We also introduce a recent approach to nucleation based on Wigner functions, which provides a solid quantum-mechanical foundation for these existing frameworks. In addition, it allows for including further quantum effects to the rate, thereby extending the validity to lower temperatures, and enabling higher precision. We conclude by discussing remaining open questions in perturbative approaches, highlighting directions for future developments.