Tuning the Josephson diode response with an ac current

TL;DR

This paper theoretically investigates how alternating current bias can tune the response of Josephson diodes, revealing regimes where they act as ideal diodes and analyzing dissipation effects.

Contribution

It introduces a theoretical framework for tuning Josephson diode responses with ac currents, identifying conditions for ideal diode behavior and residual dissipation.

Findings

Slow driving leads to ideal diode behavior with zero-voltage dc current in one direction.

Fast driving allows tunable diode efficiency but not ideal behavior.

Residual dissipation remains small across different driving regimes.

Abstract

Josephson diodes are superconducting elements that show an asymmetry in the critical current depending on the direction of the current. Here, we theoretically explore how an alternating current bias can tune the response of such a diode. We show that for slow driving there is always a regime where the system can only carry zero-voltage dc current in one direction, thus effectively behaving as an ideal Josephson diode. Under fast driving, the diode efficiency is also tunable, although the ideal regime cannot be reached in this case. We also investigate the residual dissipation due to the time-dependent current bias and show that it remains small. All our conclusions are solely based on the critical current asymmetry of the junction, and are thus compatible with any Josephson diode.