Emerging AdS from Extremally Rotating NS5-branes (0812.2234v3)

Abstract: We investigate the near-horizon limit of extremally rotating NS5-branes. The resulting geometry has SL(2,R) \times U(1)^2 isometry. The asymptotic symmetry group contains a chiral Virasoro algebra, and we obtain two different realizations depending on the boundary conditions we impose. When one of the two angular momenta vanishes, the symmetry is enhanced to AdS_3. The entropy of the boundary theory can be estimated from the Cardy formula and it agrees with the Bekenstein-Hawking entropy of the bulk theory. We can embed the extremally rotating NS5-brane geometry in an exactly solvable string background, which may yield microscopic understanding of this duality, especially about the mysterious enhancement of the symmetry from AdS_2 to AdS_3. The construction suggests emerging Virasoro symmetries in the extreme corner of the (1+5) dimensional little string theory.