Unifying The Tunneling And Anomaly Phenomena In Hawking Radiation

In this Letter we have derived the gravitational anomaly leading to the Hawking radiation from a fundamentally different perspective: it emerges due to the complimentary roles played by tunneling and (gravitational) anomaly. We have used the analogy of an early idea [6] of visualizing chiral gauge anomaly as an effect of spectral flow of the energy levels, from the negative energy Dirac sea, across zero energy level in presence of gauge interactions. This was extended to conformal anomaly in [10]. In the present work, we exploit the latter formalism in black hole physics where we interpret crossing the horizon of black hole (the zero energy level) as a spectral flow since it is also accompanied by a change of sign in the energy of the particle. Hence in our formulation the negative energy states below horizon play a similar role as the Dirac sea. We successfully recover the gravitational anomaly. email : subir−[email protected]