### 06.02.2019 (Wednesday)

#### A Worldsheet Dual for the Symmetric Orbifold

Triangular Seminar Rajesh Gopakumar (ICTS-TIFR)

 at: 16:30 City U.room BG03 abstract: We will argue that superstring theory on ${\rm AdS}_3\times {\rm S}^3\times \mathbb{T}^4$ 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 $\mathrm{Sym}^N(\mathbb{T}^4)$. The worldsheet theory, at $k=1$, is defined using the hybrid formalism in which the ${\rm AdS}_3\times {\rm S}^3$ part is described by a $\mathfrak{psu}(1,1|2)_1$ 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.