Central charges, elliptic genera, and Bekenstein-Hawking entropy in N $$ \mathcal{N} $$ = (2, 2) AdS3/CFT2

Abstract We consider N $$ \mathcal{N} $$ = (2, 2) AdS3/CFT2 dualities proposed in the large central charge limit (c → ∞) by Eberhardt. Here we propose the associated D1-D5 systems to be orbifolds of the standard N $$ \mathcal{N} $$ = (4, 4) systems, thereby elevating the dualities to the finite-c level on the boundary and to the quantum level in the bulk. In particular, we show that our brane systems yield low-energy sigma models whose subleading central charges match earlier predictions from bulk one-loop supergravity computations. In the case involving the Enriques surface, the finite-c sigma model has a non-trivial elliptic genus which we use to microscopically explain both the Bekenstein-Hawking entropy and the subleading logarithmic correction to it for the associated macroscopic black brane.