QSimFP FVD Seminar: Bubble nucleation for cosmological phase transitions

Abstract: First-order phase transitions proceed via bubble nucleation. This is true regardless of whether the transition is happening in your kettle or on a cosmological scale in the very early universe. For the latter, bubble collisions would produce a stochastic background of gravitational waves which may be observed today. This could yield quantitative information on physics beyond the Standard Model which is complementary to collider searches. Yet to realise this potential requires improving our understanding of bubble nucleation, as presently there are still huge theoretical uncertainties in the amplitude of the gravitational wave signal. I will give an overview of our present understanding of this signal, and of the tools that have been developed to compute it. Effective field theory has been at the forefront of this development, and I will outline how it can be used to solve a number of long-standing theoretical problems, with a focus on the bubble nucleation rate.

Bio: Oliver Gould is a proleptic lecturer and Royal Society Dorothy Hodgkin Fellow at the University of Nottingham. Before joining the University of Nottingham, he worked as a postdoctoral researcher at Helsinki University, and he completed his PhD at Imperial College London. In the past few years his work has focused on the theory of cosmological phase transitions, with the aim to make reliable predictions of their gravitational wave signals.