The ability to scale quantum circuits to the point where it can be fabricated to large-scale quantum processors is a fundamental requirement for a practical quantum computer. Superconducting quantum circuits are a leading technological platform with a promise to overcome the scalability challenge. Additionally, it is critical to develop new tools that allow rapid and large-scale characterisation of circuits and components. Ensuring reproducibility and uniformity across wafers and minimizing any sample-to-sample variation will directly translate to improvements in performance and reliability of superconducting quantum processors.

At the National Physical Laboratory, we are working on establishing the metrological capability needed to meet these challenges to support the UK’s quantum industry.  Here we will focus on one example of such new capability: a fully automated cryogenic probe station that has been installed at the SuperFab facility at Royal Holloway University of London. This instrument allows for DC- and RF characterization of superconducting quantum circuits across a whole wafer over the full temperature range from room temperature to 4K. This new capability will enable us to help process engineers to optimize processing techniques and provides a new measurement platform for the development of next-generation quantum metrology for quantum information applications.

We acknowledge the support of the UK government Department for Science, Innovation and Technology through the UK national quantum technologies program.

Manognya Acharya, Myunglae Jo, Sebastian de Graaf, Xiaobang Shang, Sang-Hee Shin, Daniel Stokes, Nick Ridler, Vladimir Antonov, Tobias Lindstrom

1. National Physical Laboratory, Hampton Road, Teddington TW11 0LW, United Kingdom  

2. Royal Holloway, University of London, Egham TW20 0EX, United Kingdom