The Cosmology of String and M-theory

My research will be in the field of particle cosmology. This is an area of physics that is in the overlap between our knowledge of the very small and the very large. When the universe was small and hot the properties of fundamental particles determined how it will evolve towards the cool state it is in today. By looking at the radiation left from that time we can extract information about the physics of the early universe. From these kind of observations we know that the universe must have gone through a phase of rapid expansion, that we term inflation, and that its expansion is still accelerating today due to an unknown source of energy that we term dark energy. In the field of fundamental physics string theory forms the best candidate for a description of physics at high energies and so it is natural to ask if string theory can account for inflation and dark energy. It is this question that my research will address and in particular I will look for explicit, generic situations in string theory that have a cosmology resembling our current observations. The key words here are explicit and generic. By explicit I mean that instead of using a model that fits observations and then arguing that it could theoretically be embedded in string theory I will consider set-ups that have a solid basis in string theory and look at their associated cosmology. This will lead to verifiable predictions from particular models. And by generic I mean that I will attempt to solve the problem of having to fine-tune the parameters in the theory. The motivation for this is that we should not only ask for a model that can explain inflation or dark energy but also ask that it can be realised naturally.