Seminarium "Teoria cząstek elementarnych i kosmologia"

Strongly supercooled phase transitions generically lead to strong, observable gravitational-wave signals. At their beginning, the scalar field typically transitions to a value well below the minimum of its potential. In this talk, I will discuss particle production caused by the subsequent evolution of the field. Because some modes feature temporarily tachyonic masses, they can be efficiently produced, and a significant fraction of the energy density released in the phase transition can get converted to particles rather than gradient energy. This can have wide-ranging consequences for the gravitational-wave spectrum and the bubble expansion velocity.