A Worldsheet Dual for the Symmetric Orbifold
Abstract:
We will argue that superstring theory on AdS_3xS^3xT^4 with the smallest amount of NS-NS flux
("k=1") is dual to the spacetime CFT given by the large N limit
of the free symmetric product orbifold Sym^N(T^4). The worldsheet theory, at k=1, is
defined using the hybrid formalism in which the AdS_3xS^3 part is described by a psu(1,1|2)_1 WZW model
(which is well defined).
Unlike the case for k\geq 2, it turns out that the string spectrum
at k=1 does not exhibit a long string continuum, and perfectly
matches with the large N limit of the symmetric product. The fusion
rules of the symmetric orbifold are also reproduced from the
worldsheet perspective.
This proposal therefore affords a tractable worldsheet description of
a tensionless limit in string theory.