Non-Existence of New Quantum Ergosphere Effect of a Vaidya-Type Black Hole

Hawking evaporation of Dirac particles and scalar fields in a Vaidya-type black hole is investigated by the method of generalized tortoise coordinate transformation. It is shown that Hawking radiation of Dirac particles does not exist for P₁, Q₂ components but for P₂, Q₁ components in any Vaidya-type black holes. Both the location and the temperature of the event horizon change with time. The thermal radiation spectrum of Dirac particles is the same as that of Klein-Gordon particles. We demonstrate that there is no new quantum ergosphere effect in the thermal radiation of Dirac particles in any spherically symmetry black holes.