Physical principles and predictions of a string theory based cosmology.

A wide range of features of the world we observe find their ultimate explanation in the physical laws that govern the early universe. String theory is a rigid mathematical structure, based on a simple set of physical principles, that provides a unifying framework of the physical laws that sould apply in the early universe. The principal goal of this project is to work towards a physical cosmology that is based on string theory. Such a 'string cosmology' would not only deepen our understanding of some of the most profound questions one might ask about our universe, but it would also further establish the early universe as a prime testing ground of fundamental high-energy physics. Concretely, this involves the study of the quantum dynamics near the big bang and, in particular, how our usual classical notions of space and time emerge in string theory, starting from a precise formulation of the theory in terms of a holographic field theory. We also investigate how a precise meaning can be given to the quantum state of the universe in a string theory cosmology, and we develop techniques to extract its observational consequences. The quantum state acts as a cosmological measure that selects the universe we observe from the set of all possible universes in string theory and therefore plays a key role in the observational verification of the theory.

Keywords:String theory, Cosmology

Disciplines:Astronomy and space sciences