Tuning methods for semiconductor spin--qubits

TL;DR

This paper introduces fast, reliable, and easily adaptable methods for characterizing and tuning semiconductor spin qubits, crucial for scalable quantum computing architectures, with a focus on GaAs double quantum dots.

Contribution

It develops efficient, automated tuning procedures for semiconductor spin qubits that are quick, easy to analyze, and adaptable to various quantum-dot systems, facilitating scalability.

Findings

Characterization of inter-dot tunnel coupling within seconds.

Identification of fast initialization points efficiently.

Methods are adaptable to different quantum-dot systems.

Abstract

We present efficient methods to reliably characterize and tune gate-defined semiconductor spin qubits. Our methods are designed to target the tuning procedures of semiconductor double quantum dot in GaAs heterostructures, but can easily be adapted to other quantum-dot-like qubit systems. These tuning procedures include the characterization of the inter-dot tunnel coupling, the tunnel coupling to the surrounding leads and the identification of the various fast initialization points for the operation of the qubit. Since semiconductor-based spin qubits are compatible with standard semiconductor process technology and hence promise good prospects of scalability, the challenge of efficiently tuning the dot's parameters will only grow in the near future, once the multi-qubit stage is reached. With the anticipation of being used as the basis for future automated tuning protocols, all measurements presented here are fast-to-execute and easy-to-analyze characterization methods. They result in quantitative measures of the relevant qubit parameters within a couple of seconds, and require almost no human interference.