  In the conventional scenario, the Hawking radiation is believed to be a
tunneling process at the event horizon of the black hole. In the quantum field
theoretic approach the Schwinger's mechanism is generally used to give an
explanation of this tunneling process. It is the decay of quantum vacuum into
particle anti-particle pairs near the black hole surface. However, in a
reference frame undergoing an uniform accelerated motion in an otherwise flat
Minkowski space-time geometry, in the non-relativistic approximation, the
particle production near the event horizon of a black hole may be treated as a
kind of Fowler-Nordheim field emission, which is the typical electron emission
process from a metal surface under the action of an external electrostatic
field. This type of emission from metal surface is allowed even at extremely
low temperature. It has been noticed that in one-dimensional scenario, the
Schr$\ddot{\rm{o}}$dinger equation satisfied by the created particle
(anti-particle) near the event horizon, can be reduced to a differential form
which is exactly identical with that obeyed by an electron immediately after
the emission from the metal surface under the action of a strong electrostatic
field. The mechanism of particle production near the event horizon of a black
hole is therefore identified with Schwinger process in relativistic quantum
field theory, whereas in the non-relativistic scenario it may be interpreted as
Fowler-Nordheim emission process, when observed from an uniformly accelerated
frame.
