  This paper presents a critical review of particle production in an uniform
electric field and Schwarzchild-like spacetimes. Both problems can be reduced
to solving an effective one-dimensional Schrodinger equation with a potential
barrier. In the electric field case, the potential is that of an inverted
oscillator -x^2 while in the case of Schwarchild-like spacetimes, the potential
is of the form -1/x^2 near the horizon. The transmission and reflection
coefficients can easily be obtained for both potentials. To describe particle
production, these coefficients have to be suitably interpreted. In the case of
the electric field, the standard Bogoliubov coefficients can be identified and
the standard gauge invariant result is recovered. However, for
Schwarzchild-like spacetimes, such a tunnelling interpretation appears to be
invalid. The Bogoliubov coefficients cannot be determined by using an
identification process similar to that invoked in the case of the electric
field. The reason for such a discrepancy appears to be that, in the tunnelling
method, the effective potential near the horizon is singular and symmetric. We
also provide a new and simple semi-classical method of obtaining Hawking's
result in the (t,r) co-ordinate system of the usual standard Schwarzchild
metric. We give a prescription whereby the singularity at the horizon can be
regularised with Hawking's result being recovered. This regularisation
prescription contains a fundamental asymmetry that renders both sides of the
horizon dissimilar. Finally, we attempt to interpret particle production by the
electric field as a tunnelling process between the two sectors of the Rindler
metric.
