Our research covers a range of early-universe phenomena. We aim to formulate models of the early universe based on contemporary ideas in fundamental physics, including string theory and M-theory. Testing these models against astronomical observation gives clues to the nature of physics at high energies, which are complementary to those provided by particle colliders such as the LHC.
The group is especially strong in the inflationary scenario.
Inflation is our best candidate for the origin of primordial density perturbation which is believed to have seeded the formation of structure in the universe, including stars, galaxies and ourselves. This perturbation is known from observation to be almost Gaussian.
In the last few years it has become clear that small departures from Gaussianity encode information about the inflationary era, and this has become an area of very active research. Our work includes an exploration of the possible signals in inflationary models, together with foundational work on the mechanisms which can give rise to non-Gaussian effects. This work is complemented by our expertise in comparing models with observation.
In collaboration with the theoretical particle physics group, we are interested in the consequences of cosmological phase transitions such as the one which may have ended inflation. These transitions can lead to formation of cosmic strings or other topological defects, which may be detectable through their influence on the cosmic microwave background.