Thermodynamics for higher dimensional rotating black holes with variable Newton constant

Abstract

The extensivity for the thermodynamics of general $D$-dimensional rotating black holes with or without a cosmological constant can be proved analytically, provided the effective number of microscopic degrees of freedom and the chemical potential are given respectively as $N=L^{D-2}/G, \mu= GTI_D/L^{D-2}$, where $G$ is the variable Newton constant, $I_D$ is the Euclidean action and $L$ is a constant length scale. In the cases without a cosmological constant, i.e. the Myers-Perry black holes, the physical mass and the intensive variables can be expressed as explicit macro state functions in the extensive variables in a simple and compact form, which allows for an analytical calculation for the heat capacity. The results indicate that the Myers-Perry black holes with zero, one and $k$ equal rotation parameters are all thermodynamically unstable.