Photon propagation in space-time with a compactified spatial dimension

The one-loop effects of vacuum polarization induced by untwisted fermions i n QED in a nonsimply connected space-time with topology S-1 x R-3 are inves tigated. It is found that photon propagation in this system is anisotropic, appearing several massive photon modes and a superluminal transverse mode. For small compactification radius a, the superluminal velocity increases l ogarithmically with a. At low energies the photon masses lead to an effecti ve confinement of the gauge fields into a (2 + I)-dimensional manifold tran sverse to the compactified direction. The system shows a topologically indu ced directional superconductivity. (C) 2001 Elsevier Science B.V. All right s reserved.