Near-Extremal Black Hole Thermodynamics from AdS2/CFT1 Correspondence in The Low Energy Limit of 4D Heterotic String Theory

We compute the asymptotic symmetry group of the four dimensional near-extremal Kerr-Sen black hole within an AdS2/CFT1 correspondence. We do this by performing a Robinson-Wilczek two dimensional reduction and construct a quantum theory of the remaining field content. The resulting energy momentum tensor generates an asymptotic Virasoro algebra, to s-wave, with a calculable central extension. This center in conjunction with the proper regularized lowest Virasoro eigen-mode yields the near-extremal Kerr-Sen entropy via the statistical Cardy formula. Finally we analyze quantum holomorphic fluxes of the dual CFT giving rise to a finite Hawking temperature weighted by the central charge of the near-extremal Kerr-Sen metric.
Comment: 16 pages, references added, revised for clarity. To appear in JHEP