Earlier this year, we participated in the “AI for Quantum Calibration Challenge”, which was jointly issued by Quantum Machines and Rigetti and hosted at the Israeli Quantum Computing Center (IQCC). The goal of the Challenge was to calibrate a 9-qubit Rigetti Novera QPU integrated with Quantum Machines' OPX1000 control system and NVIDIA's DGX Quantum system.

The 9-qubit QPU consists of a 3×3 array of flux-tuneable transmon qubits connected by tuneable transmon-based couplers. High-fidelity single-qubit gates require precise tuning of the qubit frequencies to effectively decouple them from one another and eliminate unwanted interactions. In contrast, two-qubit gates rely on carefully controlling the interactions between specific qubit pairs, a process facilitated by the tuneable couplers. The ability to seamlessly transition between high-fidelity 1- and 2-qubit gates demands careful tuning of the flux applied to each qubit and coupler.

Using QruiseOS, our advanced AI-driven model learning software, we leveraged the full capabilities of Quantum Machines’ hardware to rapidly tune up the QPU. Most notably, QruiseOS was able to reproducibly tune all 9 qubits and 12 couplers simultaneously – a task which must be performed daily – in under 45 minutes. This marks a significant improvement from the several hours or days typically required for manual calibration from even the most experienced engineers. This resulted in a mean randomised benchmarking (RB) single-qubit gate fidelity of 99.52% with zero qubit-qubit coupling ($g = 0$ for all 12 couplers).

Leveraging our modelling and simulation tools, we’re also able to successfully calibrate two-qubit gates, such as iSWAP and CZ. This is made possible by the extensive experiment management tools in QruiseOS, which automate a series of single- and two-qubit gate experiments to rapidly calibrate the qubit parameters. In these experiments, we saw strong population exchange indicative of high two-qubit gate fidelity.

These achievements underscore the seamless integration of Qruise’s cutting-edge software with Quantum Machines’ OPX1000 control system, Rigetti’s 9-qubit Novera QPU, and NVIDIA's DGX Quantum. We’re absolutely delighted to have demonstrated rapid, fully-parallelised bring-up using these pioneering systems and look forward to continuing to collaborate with these leading quantum hardware companies. Together, we endeavour to overcome the growing challenge of scaling quantum systems by optimising calibration processes while ensuring exceptional fidelities.

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