Characteristics of Quantum Radiation of Slowly Varying Nonstationary Kerr-Newman Black Holes

Quantum radiative characteristics of slowly varying nonstationary Kerr-Newman black holes are investigated by using the method of generalized tortoise coordinate transformation. It is shown that the temperature and the shape of the event horizon of this kind of black holes depend on the time and the angle. Further, we reveal a previously ignored relationship between thermal radiation and nonthermal radiation, which is that the chemical potential in the thermal radiation spectrum is equal to the highest energy of the negative energy state of particles in nonthermal radiation for slowly varying nonstationary Kerr-Newman black holes. Also, we show that the deduced general results can be degenerated to the known conclusion of stationary Kerr-Newman black holes.