A Note on kappa-Diagonal Surface States
  We classify all twist-even squeezed states in string field theory which are diagonal in the kappa-basis and simultaneously surface states. For this purpose, we derive a consistency condition for the maps defining kappa-diagonal surface states. It restricts these maps to a two-parameter family of Jacobi sine functions. Not all of them are admissible maps for surface states; standard requirements single out two one-parameter families containing the generalized butterfly states and the wedge states. 
Sebastian Uhlmann (MIT)