Fluxes of higher-spin currents and Hawking radiation from charged black holes

This is an extended version of the previous paper [S. Iso, T. Morita, and H. Umetsu, Phys. Rev. D 75, 124004 (2007).]. Quantum fields near horizons can be described in terms of an infinite set of two-dimensional conformal fields. We first generalize the method of Christensen and Fulling to charged black holes to derive fluxes of energy and charge. These fluxes can be obtained by employing a conformal field theory technique. We then apply this technique to obtain the fluxes of higher-spin currents and show that the thermal distribution of Hawking radiation from a charged black hole can be completely reproduced by investigating transformation properties of the higher-spin currents under conformal and gauge transformations.