FLUX TUBES AND THEIR INTERACTION IN U(1) LATTICE GAUGE-THEORY

We investigate singly and doubly charged flux tubes in U(1) lattice ga uge theory. By simulating the dually transformed path integral we are able to consider large flux tube lengths, low temperatures, and multip ly charged systems without loss of numerical precision. We simulate fl ux tubes between static sources as well as periodically closed flux tu bes, calculating flux tube profiles, the total field energy and the fr ee energy. Our main results are that the string tension in both three and four dimensions scales proportionally to the charge - which is in contrast to previous lattice results - and that in four-dimensional U( 1) there is an attractive interaction between flux tubes for beta appr oaching the phase transition. (C) 1998 Elsevier Science B.V.