Driven superconducting proximity effect in interacting quantum dots

TL;DR

This paper develops a theoretical framework for the non-equilibrium superconducting proximity effect in interacting quantum dots, highlighting how time-dependent coupling induces resonant states and enables control over quantum superpositions.

Contribution

It introduces a novel theory for the driven proximity effect in interacting quantum dots and proposes methods to generate and manipulate quantum superpositions via pulsed couplings.

Findings

Proximity effect occurs at gate-voltage-dependent resonance conditions.

Tunneling current into a normal lead reveals the proximity effect.

Pulsed couplings can generate and control superpositions of quantum-dot states.

Abstract

We present a theory of non-equilibrium superconducting proximity effect in an interacting quantum dot induced by a time-dependent tunnel coupling between dot and a superconducting lead. The proximity effect, that is established when the driving frequency fulfills a gate-voltage-dependent resonance condition, can be probed through the tunneling current into a weakly-coupled normal lead. Furthermore, we propose to generate and manipulate coherent superpositions of quantum-dot states with electron numbers differing by two, by applying pulsed oscillatory variations to the couplings between dot and superconductors.