Speaker
Description
The gravitational wave signal produced by a cosmological phase transition depends strongly on the rate of bubble nucleation. This determines the size of bubbles at collision, and consequently affects both the peak frequency and amplitude of the gravitational wave signal. Making reliable predictions of the nucleation rate is made difficult by its spacetime dependence, and by non-equilibrium aspects. In this talk, I will give an overview of recent developments in the theory of thermal bubble nucleation. I will also present nonperturbative lattice simulations for a simple real scalar theory with a tree-level barrier. The results of these simulations provide an unambiguous benchmark for perturbative calculations of the nucleation rate, and highlight the importance of higher-order corrections. For perturbative predictions, the inclusion of functional determinants is crucial for agreement with lattice results.
