Superstrings near the conformal boundary of $\rm AdS_3$

Abstract: We study worldsheet sphere amplitudes, in the RNS formalism, in superstring theory on $\text{AdS}_3\times X$ with pure NS-NS flux using the near-boundary approximation. By computing a number of amplitudes at low-lying spectral flow, we deduce a candidate for a dual CFT for generic $X$. Specialising to $X={\rm S^3}\times \mathbb{T}^4$ and with minimal NS-NS flux, i.e., to the tensionless limit, we explore the effect of the interaction term which we ignore in the near-boundary consideration. We show that amplitudes in the tensionless superstring theory on $\rm AdS_3\times S^3\times\mathbb{T}^4$ do not receive perturbative contributions from such an interaction term.