title: Persistent tunneling currents and magnetic-field effects in glasses.
abstract: Recent experiments on insulating glasses showed an unexpected variation of the dielectric constant with a static magnetic field and, in particular, oscillations with an apparent flux quantum of about 10(-5)h/e. We propose an explanation for these phenomena in terms of a model based on pairs of two-level systems. A weak interaction is shown to give rise to quantum states with a net circular current and a linear field dependence of the energy levels. Under experimental conditions, the dynamic susceptibility shows oscillatory behavior, with an effective flux quantum of the order of 10(-5)h/e.
authors.affiliation: Université Bordeaux 1, CPMOH, 351 cours de la Libération, 33405 Talence, France.
authors.forename: Alois
authors.initials: A
authors.lastname: Würger