Probing the early universe with gravitational waves.

Abstract: This talk will focus on the phenomenon of cosmological phase transitions and the possibility of them sourcing an observable gravitational wave background. I will provide an overview of the field, highlighting the active areas of research, going from fundamental physics models, through the dynamics of the phase transition, to modelling gravitational-wave backgrounds. I will explore more closely the computation of the bubble nucleation rate during a first-order phase transition, introducing the theoretical tools needed for precise phenomenological predictions. I will comment on the prospects for future detection of a gravitational-wave background coming from a cosmological phase transition in future detectors, in particular, Laser Interferometer Space Antenna (LISA).