Name: Sebastian Halter
 Institution: Max-Planck-Institute for Physics, Munich
 Title: Matter Inflation and Heisenberg Symmetry in Heterotic String Theory
 Key Words: String Inflation, Heterotic Orbifolds, Matter Inflation, Heisenberg Symmetry
 Abstract: We propose a new approach for realizing inflation in the matter sector of Heterotic string theory models. The eta-problem is solved by the Heisenberg symmetry of the Kaehler potential, which mixes a modulus with an untwisted matter field. We discuss a new mechanism to stabilize this modulus during inflation that possibly respects the Heisenberg symmetry and is compatible with stabilization of the dilaton during inflation. The inflaton resides in the matter sector of the theory and inflation ends via the waterfall mechanism of hybrid inflation.