An extremization principle for the entropy of rotating BPS black holes in AdS$_5$
Seyed Morteza Hosseini, Kiril Hristov, Alberto Zaffaroni
TL;DR
This work identifies an entropy-extremization principle for a class of 1/16 BPS rotating black holes in AdS$_5\times S^5$, showing that the Bekenstein-Hawking entropy can be obtained from the Legendre transform of $E = - i \pi N^2 \frac{\Delta_1\Delta_2\Delta_3}{\omega_1\omega_2}$ under the constraint $\Delta_1+\Delta_2+\Delta_3+\omega_1+\omega_2 = 1$. The extremization reproduces the black hole entropy and reveals a formal similarity to anomaly polynomials and the supersymmetric Casimir energy of ${\cal N}=4$ SYM, hinting at deep field-theory/gravity connections. In the special case of equal angular momenta, a dimensional reduction to four dimensions maps the problem to the well-understood attractor mechanism for static BPS black holes, providing a concrete link between five- and four-dimensional extremization. The results reinforce the idea that black hole entropy in AdS contexts can be captured by extremization principles tied to holographic anomalies and may illuminate the five-dimensional attractor structure for rotating solutions.
Abstract
We show that the Bekenstein-Hawking entropy of a class of BPS electrically charged rotating black holes in AdS$_5\times S^5$ can be obtained by a simple extremization principle. We expect that this extremization corresponds to the attractor mechanism for BPS rotating black holes in five-dimensional gauged supergravity, which is still unknown. The expression to be extremized has a suggestive resemblance to anomaly polynomials and the supersymmetric Casimir energy recently studied for $\mathcal{N}=4$ super Yang-Mills.
