Effective Boundary Field Theory for a Josephson Junction Chain with a Weak Link
arXiv:cond-mat/0501378 · doi:10.1016/j.nuclphysb.2005.01.037
Abstract
We show that a finite Josephson Junction (JJ) chain, ending with two bulk superconductors, and with a weak link at its center, may be regarded as a condensed matter realization of a two-boundary Sine-Gordon model. Computing the partition function yields a remarkable analytic expression for the DC Josephson current as a function of the phase difference across the chain. We show that, in a suitable range of the chain parameters, there is a crossover of the DC Josephson current from a sinusoidal to a sawtooth behavior, which signals a transition from a regime where the boundary term is an irrelevant operator to a regime where it becomes relevant.
30 pages, 1 .eps figure