Speaker
Description
Theories beyond the Standard Model (BSM) with classical scale invariance predict an intriguing thermal history of the early Universe. Due to the absence of dimensionful terms at tree level in these models, the electroweak phase transition (EWPT) can be significantly delayed, inducing a period of thermal inflation supercooling the Universe. As the SM quarks may remain massless at the QCD scale, the exit from this supercooled state can be triggered via a strong, first-order QCD chiral phase transition. I will discuss how the QCD phase transition can be studied with effective Polyakov loop models, with a particular focus on the impact of thermal inflation on the strongly coupled dynamics. Finally, I will present the expected gravitational wave (GW) spectra which are considerably enhanced in a supercooled Universe. This enhancement implies promising observational prospects at future GW detectors.