Particle tunnels from Garfinkle-Horne black hole and Horowitz-Strominger black hole

When the black hole radiates particles, it losses energy and shrinks, it is the contraction of the horizon that sets the tunnelling barrier. This article extents the work of M. Parikh to CH black hole and HS black hole. Applying WKB approximation, we calculate the rate of Hawking radiation and found that the rate of tunnelling equals precisely the exponent of the difference of the entropy of the black hole before and after emission. We also obtain the result that the energy spectrum of radiation deviates from the exact thermality.