Josephson junction chains with long-range interactions: Phase slip proliferation versus Kosterlitz-Thouless transition
Abstract
The role of long range badly screened Coulomb interactions in a one-dimensional chain of Josephson junctions is studied. Correlation functions for the phase correlator are obtained as a function of the Josephson coupling energy, the short range part of Coulomb repulsion and its long range component. Though quasi-long range order is no longer possible and the usual Kosterlitz-Thouless transition no longer exists, there are remnants of it. As an application, we calculate the I-V curves for Andreev reflexion when a normal metal is placed in contact with the chain. Formally, there is always an offset voltage V0 below which no current can flow, however, in some regimes V0 can be negligible. Contrary to what happens without long-range interactions, the Andreev current, as a function of applied voltage, increases faster than any power law. Signatures of long range interactions and phase slips appear in the I-V curves. Possible application for quasi one-dimensional thin superconducting wires is outlined.