By using the hybrid formalism, superstrings in four-dimensional NS-NS plane waves are studied in a manifest supersymmetric manner. This description of the superstring is obtained by a field redefinition of the RNS worldsheet fields and defined as a topological N = 4 string theory. The Hilbert space consists of two types of representations describing short and long strings. We study the physical...

We discuss a particular non-relativistic limit of NS-NS gravity that can be taken at the level action and equations motion, without imposing any geometric constraints by hand. This relies on fact terms diverge in come from Vielbein Einstein-Hilbert term kinetic Kalb-Ramond two-form field cancel against each other. cancelling divergences is target space analogue similar cancellation takes place ...