Quantum thermal effect of nonstationary Kerr-Newman black hole

The Hawking radiation and the entropy of non-stationary Kerr-Newman black hole whose metric changes slowly are calculated via the method of Damour etc. and the thin film brick-wall model. First, we obtain the Hawking radiation temperature and the thermal spectrum formula. Second, we get the entropy density at every point of the horizon surface as well as the total entropy of the black hole, which is just the Bekenstein-Hawking entropy and relies on the notion of the local equilibrium crucially that can be met if the evaporation and the accretion of the black hole is negligible. The results show that the temperature of the event horizon depends on the time and the angle, and the entropy of the non-stationary black hole is also proportional to the horizon area with appropriate cutoff relationship as in the case of stationary black holes.