Automated Calibrations in 6-Qubit Quantum Dot Spin Devices in Silicon*

Quantum Inspire is a cloud platform giving access to quantum computers based on superconducting and semiconducting qubits. Structured tune-up and automated calibration techniques are vital for keeping these systems available online. In this talk, we will discuss the tune-up and automated calibration techniques utilized in our new six-qubit device [1] based on electron spins in silicon. The qubits are hosted in a linear array of six quantum dots in a SiGe/²⁸Si/SiGe heterostructure grown inhouse at QuTech [2]. Readout is done using Pauli Spin Blockade (PSB), single qubit operation through EDSR, and two-qubit gates are symmetric CZ gates.

Automated calibrations are performed using a directed acyclic graph to keep our qubits up and running. Nodes in the graph represent different calibration steps starting from tuning the charge sensor up to compensating for qubit crosstalk. We will go through the different calibration steps needed to keep a spin qubit device online. Finally, we will show some of the latest performance metrics on single and two-qubit gates reached by automated calibration and elaborate on our future plans.

References:

[1] S. G. J. Philips, M. T. Mądzik, S. V. Amitonov, S. L. de Snoo, M. Russ, N. Kalhor, C. Volk, W. I. L. Lawrie, D. Brousse, L. Tryputen, B. Paquelet Wuetz, A. Sammak, M. Veldhorst, G. Scappucci and L. M. K. Vandersypen, "Universal control of a six-qubit quantum processor in silicon," Nature 609, 919 (2022).

[2] D. D. Esposti, B. P. Wuetz, V. Fezzi, M. Lodari, A. Sammak and G. Scappucci, "Wafer-scale low-disorder 2DEG in 28Si/SiGe without an epitaxial Si cap," Applied Physics Letters, vol. 120, no. 18, p. 184003, 2022.