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Simulation results for an interacting pair of resistively shunted Josephson junctions

Philipp Werner·Gil Refael·Matthias Troyer
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Abstract

Using a new cluster Monte Carlo algorithm, we study the phase diagram and critical properties of an interacting pair of resistively shunted Josephson junctions. This system models tunneling between two electrodes through a small superconducting grain, and is described by a double sine-Gordon model. In accordance with theoretical predictions, we observe three different phases and crossover effects arising from an intermediate coupling fixed point. On the superconductor-to-metal phase boundary, the observed critical behavior is within error-bars the same as in a single junction, with identical values of the critical resistance and a correlation function exponent which depends only on the strength of the Josephson coupling. We explain these critical properties on the basis of a renormalization group (RG) calculation. In addition, we propose an alternative new mean-field theory for this transition, which correctly predicts the location of the phase boundary at intermediate Josephson coupling strength.

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Philipp Werner, Gil Refael, Matthias Troyer. 2005-08-05. Simulation results for an interacting pair of resistively shunted Josephson junctions. https://doi.org/10.1088/1742-5468%2F2005%2F12%2Fp12003

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