Black hole radiation with high frequency dispersion - art. no. 084023

We consider one model of black hole radiation in which the equation of moti on of a matter field is modified to cut off high frequency modes. The spect rum in the model has already been analytically derived in the low frequency range, which has resulted in the Planckian distribution of the Hawking tem perature, On the other hand, it has been numerically shown that its spectru m deviates from the thermal one in the high frequency range. In this paper, we analytically derive the form of the deviation in the high frequency ran ge. Our result can qualitatively explain the nature of the numerically calc ulated spectrum. The origin of the deviation is clarified by a simple discu ssion.