2 00 1 New physics in the charged relativistic Bose gas using zeta - function regularization ? 1

The multiplicative anomaly, recently introduced in QFT, plays a fundamental role in solving some mathematical inconsistencies of the widely used zeta-function regularization method. Its physical relevance is still an open question and is here analyzed in the light of a non-perturbative method. Even in this approach the “different physics” seems to hold and not to be easily removable by renormalization.