Waiting time distributions in a two-level fluctuator coupled to a superconducting charge detector

TL;DR

This paper investigates charge fluctuations in a two-level system coupled to a superconducting charge detector, using waiting time distributions to extract asymmetric tunneling rates, advancing understanding of quantum dot charge dynamics.

Contribution

It introduces a method to analyze waiting time distributions in a two-level fluctuator coupled to a superconducting detector, revealing asymmetric tunneling rates.

Findings

Asymmetric electron tunneling rates were identified.

Waiting time distributions match theoretical predictions.

Charge fluctuation dynamics resemble quantum dot behavior.

Abstract

We analyze charge fluctuations in a parasitic state strongly coupled to a superconducting Josephson-junction-based charge detector. The charge dynamics of the state resembles that of electron transport in a quantum dot with two charge states, and hence we refer to it as a two-level fluctuator. By constructing the distribution of waiting times from the measured detector signal and comparing it with a waiting time theory, we extract the electron in- and out-tunneling rates for the two-level fluctuator, which are severely asymmetric.