Noam Levi (Tel Aviv)”Cosmological Phase Transitions – From Fundamental Theory to Detectable Signals”

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Abstract: 

Detecting a Stochastic Gravitational Wave Background (SGWB) signal from cosmological phase transitions could provide insights into the early epochs of the universe. However, connecting measurements to underlying theories is challenging due to various models producing similar GW signals. In this talk, I will discuss an example of mapping UV theory to expected signals, specifically the parametric scaling of supercooled phase transitions typical of theories with mainly spontaneously broken conformal symmetry. In these setups, the fate of the flat direction depends on its coupling strength to other states, which must be within a specific window for supercooling to be viable. We derive the supercooling window for well-known models and demonstrate that relevant deformations away from conformality can shrink or enlarge the supercooling window for weakly coupled theories. At strong coupling, we revise standard bounds on the number of de-confined degrees of freedom allowing supercooling. 

Reference: http://arxiv.org/abs/2212.08085.