Seminarium "Teoria cząstek elementarnych i kosmologia"

Scale hierarchies are required to reliably describe the thermodynamics of cosmological first-order phase transitions using perturbation theory. At finite temperature, such a hierarchy is provided naturally. One can then use this hierarchy to construct a three-dimensional effective field theory (EFT) that systematically includes thermal resummations to all orders.Using this EFT setup, I discuss completing the perturbative program for equilibrium thermodynamics of cosmological first-order phase transitions by determining the finite-temperature effective potential of gauge-Higgs theories at their perturbative limit, reaching next-to-next-to-next-to-next-to-leading order (N4LO) [1].I then explore the limitations of thermal EFTs, discussing their regime of validity and the conditions under which thermally induced higher-dimensional operators become relevant for gravitational-wave predictions. [1] A. Ekstedt, P. Schicho, and T. V. I. Tenkanen, Cosmological phase transitions at three loops: The final verdict on perturbation theory, Phys. Rev. D 110, 096006 (2024), [2405.18349].