Cornering the unphysical vertex

Understand

In the classical pure spinor worldsheet theory of AdS5xS5 there are some vertex operators which do not correspond to any physical excitations.

• We study their flat space limit.
• We find that the BRST operator of the worldsheet theory in flat space-time can be nontrivially deformed without deforming the worldsheet action.
• Some of these deformations describe the linear dilaton background.