Abstract:
Gravitational waves (GW) from cosmological phase transitions bear huge discovery
potential and can be probed by planned future space-based GW observatories.
Complementary to current and future collider experiments, such GW signatures can
offer a powerful probe for beyond the Standard Model physics. Predictions for
stochastic GW spectrum of a cosmological origin are often plagued by large
theoretical uncertainties related to low-order perturbative computation of
thermodynamic properties of a phase transition. In this talk, I will discuss how the
most accurate predictions to date -- that reduce theoretical uncertainties by orders
of magnitude -- have been obtained, in terms of effective field theory methods in
high temperature field theory. Despite these improvements, computation of
thermodynamic properties should still be improved in order to make reliable
predictions for GW spectrum. I will discuss pertubative expansion of thermal
parameters, and an ambitious task to push perturbation theory to its limits, by
computing all first few available orders, before expansion becomes non-perturbative
due to the Linde's Infrared Problem.