On tachyons, gauged linear sigma models, and flip transitions

We study systems of multiple localized closed string tachyons and thephenomena associated with their condensation, in C3/ZN nonsupersymmetricnoncompact orbifold singularities using gauged linear sigma modelconstructions, following hep-th/0406039. Our study reveals close connectionsbetween the combinatorics of nonsupersymmetric flip transitions (betweentopologically distinct resolutions of the original singularity), the physics oftachyons of different degrees of relevance and the singularity structure of thecorresponding residual endpoint geometries. This in turn can be used to studythe stability of the phases of gauged linear sigma models and gain qualitativeinsight into the closed string tachyon potential.Comment: Latex, 38 pages, 7 eps figs. v2. minor modification