Modern theoretical cosmology is concerned with the application of new theories of particle physics and gravitation to understanding the evolution of the Universe from the earliest time to the present day. There are two important reasons for doing this: (i) to understand the Universe we observe around us today and (ii) to test new particle physics theories and gravity theories against observation.

Astroparticle Physics (also known as Particle Cosmology) relies on the fact that different theories make different predictions about the evolution of the Universe and therefore about the present-day state of the Universe. One in effect uses the Universe as a 'cosmic collider', with the telescopes used by astronomers and underground experiments used to detect dark matter playing the role of the particle detectors of collider experiments. The results of Astroparticle Physics complement those of colliders such as the CERN Large Hadron Collider. The 'cosmic collider' reaches energies vastly larger than those that can be reached by any Earth-bound collider.

Lancaster has been at the leading edge of research in theoretical cosmology and astroparticle physics since it became an established field in the early 1980's.

A major part of the group's research is focused on the origin and nature of the primordial density perturbation, which serves as the "seed" for the cosmic microwave background temperature fluctuations and the large-scale cosmological structures we observe in the Universe today. The group has made important contributions to inflation theory, which accounts for the primordial density perturbation, in particular via the development of scalar and vector inflaton and curvaton models, inflation models based on weakly-interacting dark matter particles, and supersymmetric inflation models. It has also made fundamental contributions to dark matter and baryogenesis, the cosmology of supersymmetric particle theories, Q-balls in supersymmetric cosmology, primordial magnetic fields, and many other topics in modern cosmology and astroparticle physics.

Key Research

  • Inflation Theory and Primordial Perturbations
  • Scalar and Vector Curvaton Theory
  • Dark Matter and Baryogenesis
  • Cosmology of Supersymmetry