Particle Physics Seminar : The supercooling window at weak and strong coupling

Abstract:

We clarify the parametric scaling of supercooled phase transitions which are typical of theories where conformal symmetry is (mainly) spontaneously broken. In these setups the fate of the flat direction depends on the strength of its coupling to the other states. The latter needs to be in a particular window such that supercooling is viable. The upper bound on the coupling arises from forbidding nucleation before the vacuum energy overcomes the radiation one, while the lower bound requires nucleation during a finite inflationary period. At weak coupling, if thermal fluctuations dominate the tunneling rate, we show how the lower bound depends on the spin-statistics of the thermal states coupled to the flat direction. In particular, we find that bosonic states enlarge the supercooling window compared to fermionic ones because of the thermally induced cubic. At strong coupling, we revise standard bounds on the number of deconfined d.o.fs allowing supercooling.

Seminar Organizers: Dr. Michael Geller & Dr. Adi Ashkanzi