Four Quantum Conservation Laws for Black Hole Stationary Equilibrium   Radiation Processes
  The classical first law of thermodynamics for a Kerr-Newman black hole (KNBH) is generalized to a law in quantum form on the event horizon. Then four quantum conservation laws on the KNBH equilibrium radiation process are derived. The Bekenstein-Hawking relation ${\cal{S}}={\cal{A}}/4$ is exactly established. It can be inferred that the classical entropy of black hole arises from the quantum entropy of field quanta or quasi-particles inside the hole. 
S. Q. Wu, X. Cai