Hawking radiation via tunneling from Kerr black holes

In this paper, Parikh's recent work, which treats Hawking radiation as a tunneling process in a spherically symmetric spacetime, is extended to the stationary axisymmetric Kerr spacetime. A generalized Painleve coordinate system (Painleve-Kerr coordinates) is introduced. The new coordinates are well-behaved at the event horizon. Constant-time slices are just flat Euclidean space in radial and satisfy Landau's condition of clock synchronization. The tunneling process across the Kerr black hole event horizon is investigated and the correctd radiation spectrum is obtained. The result is consistent with an underlying unitary theory.