Oxford University, Oxford, UK

String Theory and the First Half of the Universe

Abstract:  The period between inflation and nucleosynthesis can last for thirty orders of magnitude
of time and represent half the lifetime of the universe
on a logarithmic scale. But yet, there are minimal  observational constraints on this epoch. String cosmologies motivate a rich set of modifications
from the standard radiation-dominated post-inflationary assumption of Lambda CDM. In particular, string cosmology suggests the likelihood of moduli-dominated cosmologies through kination, tracker and matter epochs. I review the possible scenarios and observational possibilities, including a novel percolation scenario for formation of cosmic string networks.