Dual CFT on a dyonic Kerr-Sen black hole and its gauged and ultraspinning counterparts
Muhammad F. A. R. Sakti, Piyabut Burikham
Abstract
We demonstrate strong evidence of entropy matching that rotating dyonic black holes in Einstein-Maxwell-Dilaton-Axion theory is holographically dual to a 2D conformal field theory (CFT). We first investigate the duality on a dyonic Kerr-Sen black hole with nonvanishing dilaton and axion charges. The near-horizon geometry of extremal dyonic Kerr-Sen spacetime possesses the $SL(2,R)\ifmmode\times\else\texttimes\fi{}U(1)$ isometry where the asymptotic symmetry group method can be used to find the corresponding central charge. We find two different branches of masses which correspond to CFT with two different central charges, ${c}_{L}=12a{m}_{+}$ and ${c}_{L}=12a{m}_{\ensuremath{-}}$. The exact agreement between the Bekenstein-Hawking entropy and entropy from CFT is then found also in two different branches of extremal entropy. Furthermore, we demonstrate that this duality is robust insofar for nonzero anti--de Sitter (AdS) length. The duality holds for both dyonic Kerr-Sen--AdS black hole and its ultraspinning counterpart. In both cases, we obtain the expected entropy from CFT which matches exactly with the Bekenstein-Hawking entropy. Since dyonic and axion charges are proportional to $1/m$, we note that there are possibly more than two branches of the central charge for nonzero AdS length in terms of mass. When we turn off dyonic charge, the axion charge vanishes, giving the results of Kerr-Sen--AdS black hole. Moreover, when we assume the equal electromagnetic charges, it recovers the results when the dilaton charge vanishes. Lastly, we compare the results of a dyonic Kerr-Sen--AdS black hole and its ultraspinning counterpart to those of the dyonic Kerr-Newman--AdS black hole and the ultraspinning counterpart. Depending on the dyonic charge parameters, it is found that an extremal ultraspinning dyonic Kerr-Sen--AdS black hole is not always superentropic.