O(ALPHA) RADIATIVE CORRECTION TO THE CASIMIR ENERGY FOR PENETRABLE MIRRORS

The leading radiative correction to the Casimir energy for two paralle l penetrable mirrors (realized by delta-function potentials) is calcul ated within QED perturbation theory. It is found to be of order ct lik e the known radiative correction for ideally reflecting miners from wh ich it differs, for a mirror distance much larger than the electron Co mpton wavelength, only by a monotonic, powerlike function of the frequ ency at which the mirrors become transparent. This shows that the O(al pha(2)) radiative correction calculated recently by Kong and Ravndal f or ideally reflecting mirrors on the basis of effective field theory m ethods remains subleading even for the physical case of penetrable mir rors. [S0031-9007(98)07449-3].