Speaker
Description
Gravitational waves (GWs) open a new window onto physics beyond the Standard Model (BSM). Many BSM theories predict a first-order phase transition (FOPT) in the early Universe, during which bubble dynamics in the primordial plasma source a stochastic GW background (SGWB) within reach of future detectors such as the Laser Interferometer Space Antenna (LISA). Predicting this signal reliably requires control over physics across vastly different scales: the microscopic nucleation of bubbles, the dynamics of their walls, and the macroscopic motion of the plasma. I review the dynamics of a FOPT and discuss recent progress on uncertainties arising from the treatment of infrared divergences in finite-temperature field theory. These uncertainties can exceed the projected experimental precision, making state-of-the-art thermal effective field theory essential for a robust interpretation of a future signal.