My research lies at the intersection of particle physics, cosmology and astrophysics. I have worked on a variety of topics in early Universe physics, including leptogenesis and inflation. In recent years much of my work has focussed on astroparticle probes of fudnamental physics, including superradiance, neutron stars, and axions/ALPs and in particular dark matter. Much of my work focusses on using non-equilibrium field theory to solve challenging problems in astroparticle physics.  More recnetly I have developed an interest in high-frequency gravitational waves.