Heterotic Strings on T3/Z2, Nikulin involutions and M-theory
Ida Zadeh (JGU Mainz)

I will discuss compactification of the heterotic string on the smooth, flat 3-manifold T3/Z2, without supersymmetry. The low energy dynamics of the corresponding ten dimensional heterotic supergravity will be described. The semi-classical theory has both Coulomb and Higgs branches of non-supersymmetric vacua. An exact worldsheet description of the compactification will then be presented using the framework of asymmetric orbifolds of T3, where the orbifold generator involves a Nikulin non-symplectic involution of the even self-dual lattice of signature (19,3). This construction gives a novel conformal field theory description of the semi-classical field theory moduli space and reveals a rich pattern of transitions amongst Higgs and Coulomb branches.