We calculate the entropies of the system of classical particles and a quantum scalar field by using the brick wall method in thermal bath in a charged Kerr black hole spacetime. Their leading terms at Hartle-Hawking temperature $T_H = \kappa/(2 \pi) $ are given by $ S_{ cl} \approx N \ \ln \left( \frac{ A_b}{ \epsilon^2} \right)$, and $S \approx N' \frac{ A_H}{ \epsilon^2}$, where $A_b$ and $A_H$ are the area of the box and the horizon respectively.
Categories: hep-th