Closed string tachyon condensation on twisted circles

Abstract

We study IIA/B string theory compactified on twisted circles. These models possess closed string tachyons and reduce to type-0B/A theory in a special limit. Using methods of gauged linear sigma models and mirror symmetry we construct a conformal field theory which interpolates between these models and flat space via an auxiliary Liouville direction. Interpreting motion in the Liouville direction as renormalization group flow, we argue that the end point of tachyon condensation in all these models (including 0B/A theory) is supersymmetric type-II theory. We also find a zero-slope limit of these models which is best described in a T-dual picture as a type-II NS-NS fluxbrane. In this limit tachyon condensation is an interesting and well posed problem in supergravity. We explicitly determine the tachyon as a fluctuation of supergravity fields, and perform a rudimentary numerical analysis of the relevant flows.