A "push of a button" bootstrap for quantum dot qubit tuning

Scaling quantum dot (QD) qubits into large arrays requires efficient, reliable, and automated methods for selecting gate voltages to operate each qubit. Traditionally, scientists solve this problem by carefully choosing gate voltages by hand, confining electrons within QDs while forming reservoirs and setting up nearby auxiliary devices, such as single-electron-transistor charge sensors. In this talk, we present a software framework, FrEQuENTS, that automates this process and enables a “single push of a button” tuning. We demonstrate its use to automatically place a three-channel QD qubit device into the proper operating regime starting from zero electron accumulation – a truly cold start. FrEQuENTS provides a software architecture to keep track of the numerous interactions between all the parts of a functional QD qubit device: the gates, the ohmic contacts, and the two-dimensional electron gas. The framework follows a modular design; as each stage finishes, the device is in a specific and well-defined state, independent of gate-specific information such as individual tuning parameter values. FrEQuENTS also enables a full assessment of the performance of specific gates in the device as the software bootstraps it from no accumulation to the launching point for a qubit-specific tune-up.