THERMAL PARTITION-FUNCTION OF PHOTONS AND GRAVITONS IN A RINDLER WEDGE

The thermal partition function of photons in any covariant gauge;and g ravitons in the harmonic gauge, propagating in a Rindler wedge, are co mputed using a local zeta-function regularization approach. The correc t Planckian leading order temperature dependence T-4 is obtained in bo th cases. For the photons, the existence of a surface term giving a ne gative contribution to the entropy is confirmed, as earlier obtained b y Kabat, but this term is shown to be gauge dependent in the four-dime nsional case and, therefore, is discarded. It is argued that similar t erms could appear dealing with any integer spin s greater than or equa l to 1 in the massless case and in more general manifolds. Our conject ure is checked in the case of a graviton in the harmonic gauge, where different surface terms also appear, and physically consistent results arise dropping these terms. The results are discussed in relation to the quantum corrections to the black hole entropy.