Effective AdS3/CFT2

A bstract In [1], it was pointed out that superstring theory on AdS 3 with ( NS , NS ) B -field background and R AdS / l s = $$ \sqrt{k} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>k</mml:mi> </mml:msqrt> </mml:math> &lt; 1 is dual to a symmetric product CFT deformed by an operator in the ℤ 2 twisted sector. We generalize the analysis of [1] to k &gt; 1, and show that the resulting picture matches that discussed in the bosonic case in [2]. We argue that in the critical case, k = 1 [3], the ℤ 2 twisted deformation remains non-trivial. This resolves some confusions in the literature.