Resonance in the nonadiabatic quantum pumping of the time-dependent Josephson junction

TL;DR

This paper explores how high-frequency driving causes resonances in nonadiabatic quantum transport within a Josephson junction, significantly enhancing supercurrent via Floquet theory analysis.

Contribution

It introduces a detailed Floquet-based analysis of resonance phenomena in nonadiabatic Josephson junctions with time-dependent potentials, revealing phase-dependent quasiparticle bound states.

Findings

Resonances occur when Floquet wavevectors match bound quasiparticle states.

Supercurrent is significantly enhanced at resonance conditions.

Resonance positions depend on the phase difference between superconductors.

Abstract

In this work, we investigated the nonadiabatic transport properties of the one-dimensional time-dependent superconductor-normal metal-superconductor (SNS) Josephson junction biased by a current source and driven by a high-frequency-ac-gate-potential applied to the normal-metal layer. BCS superconductors are considered and treated with the time-dependent Bogoliubov-de Gennes equation. Using Floquet theory, we compute the transmission coefficients and the Wigner-Smith delay times as a function of the incident energy and find that they display resonances when one of the electron or hole Floquet wavevectors coincides with the bound quasiparticle state within the superconducting energy gap. The resonance varies with the phase difference between the two superconductors as a result of the bound quasiparticle level displacement. The supercurrent flowing through the SNS junction is dramatically enhanced by the resonances.