Fermion analysis of IR modified Hořava–Lifshitz gravity: tunneling and perturbation perspectives

Abstract

In this paper, we investigate the fermion Hawking radiation and quasinormal (QN) modes in infrared (IR) modified Hořava–Lifshitz (HL) gravity under tunneling and perturbation perspectives. Firstly, through the fermion tunneling in IR modified HL gravity, we obtain the Hawking radiation emission rate, tunneling temperature and entropy for the Kehagias–Sfetsos black hole. It is found that the results of fermion tunneling are consistent with the thermodynamics results obtained by calculating surface gravity. Secondly, we numerically calculate the low-lying QN mode frequencies of fermion perturbations by using WKB formulas including the third-order and sixth-order approximations simultaneously. It turns out that the actual frequency of fermion perturbation is larger than that in the Schwarzschild case, and the damping rate is smaller than that for the pure Schwarzschild. The results of fermion perturbation suggest the QN modes could live longer in HL gravity.