TRANSPORT IN JOSEPHSON JUNCTION WITH TIME DELAY AND COUPLING BETWEEN NOISE TERMS

Abstract

The transport of a spatially periodic system with time delayed feedback driven by coupled noise terms is investigated. A general approximate equation of the current is derived. For the superconduction Josephson junction, it is found that suitable time delay can enhance the current in the system. In the presence of the coupling between noise terms, the current direction is determined by the sign of the coupling. The negative coupling can induce positive current, while the positive coupling can induce negative current. The absolute value of the current is a peaked function of the additive noise but a monotonically increasing function of the multiplicative noise. Numerical simulations are in good agreement with the approximate theoretical results.