Neutrino quasinormal modes of the Reissner-Nordström black hole

The neutrino quasinormal modes of the Reissner-Nordstr\"om (RN) black holeare investigated using continued fraction approach. We find, for large angularquantum number, that the quasinormal frequencies become evenly spaced and thespacing of the real part depends on the charge of the black hole and that ofthe imaginary part is zero. We then find that the quasinormal frequencies inthe complex $\omega$ plane move counterclockwise as the charge increases. Theyget a spiral-like shape, moving out of their Schwarzschild value and ``loopingin" towards some limiting frequency as the charge tends to the extremal value.The number of the spirals increases as the overtone number increases but itdecreases as the angular quantum number increases. We also find that both thereal and imaginary parts are oscillatory functions of the charge, and theoscillation becomes faster as the overtone number increases but it becomesslower as the angular quantum number increases.Comment: 11 pages, 3 figure