Optical approach for the thermal partition function of photons

The optical manifold method to compute the one-loop effective action in a static space-time is extended from the massless scalar field to the Maxwell field in any Feynman-like covariant gauge. The method is applied to the case of the Rindler space obtaining the same results as the point-splitting procedure. The result is free from Kabat’s surface terms which instead affect the ζ-function or heat-kernel approaches working directly in the static manifold containing conical singularities. The relation between the optical method and the direct ζ-function approach on the Euclidean Rindler manifold is discussed both in the scalar and the photon cases. Problems with the thermodynamic selfconsistency of the results obtained from the stress tensor in the case of the ∗Electronic address: [email protected] †Electronic address: [email protected]