Splitting a single Cooper-pair with microwave light

TL;DR

This paper demonstrates real-time observation of Cooper pair breaking and recombination in a superconducting double quantum dot, and shows that microwave photons can induce pair breaking, revealing new insights into superconducting quantum dynamics.

Contribution

It introduces a method to detect single Cooper pair breaking events via quantum capacitance measurements and shows microwave photons can break pairs, a novel control mechanism.

Findings

Real-time detection of Cooper pair dynamics

Microwave photons can break single Cooper pairs

Quantum capacitance depends on Cooper pair state

Abstract

We measure an aluminum superconducting double quantum dot and find that its electrical impedance, specifically its quantum capacitance, depends on whether or not it contains a single broken Cooper pair. In this way we are able to observe, in real time, the thermally activated breaking and recombination of Cooper pairs. Furthermore, we apply external microwave light and break single Cooper pairs by the absorption of single microwave photons.