Closed string tachyons in a smooth curved background
  Closed string tachyon condensation has been studied in orbifolds C^2/Z_{N,p} of flat space, using the chiral ring of the underlying N=2 conformal field theory. Here we show that similar phenomena occur in the curved smooth background obtained by adding NS5-branes, such that chiral tachyons are localised on lens submanifolds SU(2)/Z_{N,p}. We find a level-independent subring which coincides with that of C^2/Z_{N,p}, corresponding to condensation processes similar to those of hep-th/0111154. We also study level-dependent chiral tachyons. 
Pedro Bordalo