Frequency Windows of Absolute Negative Conductance in Josephson Junctions

TL;DR

This paper investigates anomalous conductance phenomena in Josephson junctions driven by combined ac and dc currents, revealing frequency-dependent windows of absolute negative conductance where voltage and current directions oppose.

Contribution

It demonstrates the existence of frequency windows of absolute negative conductance in Josephson junctions under combined ac and dc driving, a novel observation in this context.

Findings

Identification of frequency windows with negative conductance

Demonstration of voltage-current opposition in specific regimes

Analysis of conductance behavior under combined ac and dc currents

Abstract

We report on anomalous conductance in a resistively and capacitively shunted Josephson junction which is simultaneously driven by ac and dc currents. The dependence of the voltage across the junction on the frequency of the ac current shows windows of absolute negative conductance regimes, i.e. for a positive (negative) dc current, the voltage is negative (positive).