A Note on Vacuum Polarisation and Hawking Radiation
  We re-examine vacuum polarisation of a scalar field in a quasi-local volume including the horizon. We find that Hawking radiation rate is derived as a pure decay of vacuum due to scalar field interaction with classical gravity exactly in the same way as the origin of vacuum polarisation effect in Electrodynamics. 
Arundhati Dasgupta, Shohreh Rahmati
gr-qc hep-th