Interplay of Pauli blockade with electron-photon coupling in quantum dots

TL;DR

This paper develops a theoretical framework to analyze how a double quantum dot interacts with a microwave resonator during Pauli blockade, enabling inference of current leakage and microscopic parameters from resonator signals.

Contribution

The work introduces a generalized input-output theory to connect microwave resonator responses with transport properties in Pauli blockade regimes, including effects of valley degeneracy and back-action.

Findings

Resonator output can reveal leakage current details.

Valley quasi-degeneracy limits measurement schemes.

Resonator response can estimate unknown DQD parameters.

Abstract

Both quantum transport measurements in the Pauli blockade regime and microwave cavity transmission measurements are important tools for spin-qubit readout and characterization. Based on a generalized input-output theory we derive a theoretical framework to investigate how a double quantum dot (DQD) in a transport setup interacts with a coupled microwave resonator while the current through the DQD is rectified by Pauli blockade. We show that the output field of the resonator can be used to infer the leakage current and thus obtain insight into the blockade mechanisms. In the case of a silicon DQD, we show how the valley quasi-degeneracy can impose limitations on this scheme. We also demonstrate that a large number of unknown DQD parameters including (but not limited to) the valley splitting can be estimated from the resonator response simultaneous to a transport experiment, providing more detailed knowledge about the microscopic environment of the DQD. Furthermore, we describe and quantify a back-action of the resonator photons on the steady state leakage current.