The Kerr black hole is regarded as a thermodynamical system composed by two subsystems, the outer horizon (event horizon) and the inner horizon (Cauchy horizon). The black hole entropy is contributed by both the area of oilier horizon and the minus area of inner horizon. The entropy satisfies Nernst theorem.
Based on Glaubers theory, a single spin transition critical dynamics is presented. The distinguishing features of this theory are that it is suitable for arbitrary spin systems, the transition probability can be determined by a universal expression and the indefinite constant in Glaubers theory is eliminated.
