Microwave metrology for superconducting quantum circuits

Computers utilising quantum effects can process certain types of data far quicker than classical computers and the Strategic Research Agenda for Metrology in Europe has identified the need for further fundamental metrology in this area.

Quantum operations rely on materials that become ‘super conducting’ at cryogenic (millikelvin) temperatures. Developing quantum computers will require the integration of microwave components inside such cryogenic systems. However, no established technology can perform accurate microwave waveform generation and detection, and no SI traceability exists for components, at such extremely low temperatures.

Quantum sensors and quantum arrays (SQUID) made of either high- or low-temperature superconductors have been fabricated and employed for sensing applications but the use of such circuits for metrological applications at very low power levels have not been investigated.

This project will address this using a combination of different technologies including superconductors, microwaves, semiconductors, optics and plasmonics. Validated techniques for the generation and detection of ultrafast opto-electronic waveforms will be established for components exceeding 100 GHz at cryogenic temperatures with traceability to the SI. New quantum sensor technologies for measuring microwave power, waveforms and microwave electric fields in the frequency range 1-12 GHz will be modelled, developed and validated. The performance of these sensors will be assessed at low temperatures and compared to the current state of the art measurement techniques.

This work will establish the foundations of a ‘microwave toolbox’ in Europe, providing enhanced measurements and standards for the emerging quantum industry and sectors such as telecommunications, cryogenic systems for QT, and medical imaging.