Flow of Geometries and Instantons on the Null Orbifold
  We study condensation of twisted sector states in the null orbifold geometry. As the singularity is time-dependent, we probe it using D-Instantons. We present evidence that the null-orbifold flows to the $Z_N$ orbifold. We also comment on the subtleties of quantizing the closed superstring in this background. 
Micha Berkooz, Zohar Komargodski, Dori Reichmann, Vadim Shpitalnik