Quantum microwave transmitters show their potential

How will quantum mechanics influence tomorrow’s industry? What if the applications of these technologies reside in a future much closer than one can imagine? Jérôme Bourassa, associate professor at the Department of Physics at the Université de Sherbrooke and member of the Institut quantique (IQ), is working on the design of a quantum technology that shows great potential.

Between January 2016 and 2017, the National Research Council of Canada (NRC) and the Department of National Defence (DND) contacted the research group of which Jérôme is part of to study the potential of quantum technologies for surveillance and remote sensing in the field of quantum microwaves. From this work came a publication in Applied Physics Letters: Quantum-Enhanced Noise Radar, in January 2019.

From Traditional to Quantum Technologies

The article highlights the possibilities of using the nature of quantum states of light in the microwave field. The ultimate goal? To see if the use of superconducting circuit technology is possible to develop new remote sensing, telemetry, and imaging tools. The basis of these technologies is a quantum transmitter of tangled microwave signals, that is, they have more correlations than signals from traditional conventional transmitters. With the gain made possible with quantum correlations, the new quantum transmitter could increase the sensitivity and precision of measures made with microwaves. For example, it could allow the update of radar systems capable of detecting stealth targets, or even medical imaging systems that deliver lower doses of microwave radiation to the patient.

The realization of such a transmitter is a major technological challenge. Indeed, the fragile quantum signals are generated in a cryogenic system at a temperature near absolute zero, which is highly isolated from the outside world. To make them useful for measurements, these signals must be brought outside of the cryogenic system while maintaining their original correlations as much as possible.

Jérôme Bourassa sees an interest. “I saw the potential. I was very excited to take signals that are typically confined in an excessively cold system and take out those quantum signals that are, by definition, fragile, and use them in the open, warm, noisy environment,” explains Jérôme.

“During the project, I took care of the theoretical calculations, forecasts, optimization, and I also determined the technical feasibility of everything, hoping to have a tangible gain compared to traditional, classic technologies,” shares Jérôme. With this work, Jérôme and the team he is part of were able to determine a first concept for a functional microwave quantum transmitter. With his collaborator, Professor Christopher Wilson of the Institute for Quantum Computing at the University of Waterloo, the concept was realized in a laboratory. The results of this work, published in Applied Physics Letters, demonstrated the great potential of the technology.

A New Business to Implement Fundamental Physics

The team’s research on quantum microwave transmitters for the publication has had positive and conclusive results. In order to exploit the applications offered by this technology, Jérôme founded a new company, Qubic, in partnership with his collaborators. “Our first goal is to design this quantum microwave transmitter that can operate at room temperature. We’re the first company in the world dedicated to the development of quantum microwave technologies for remote sensing and imaging,” explains Jérôme.

At this time, microwaved-based medical imaging systems are used to detect breast cancer. However, there is still concern about microwave radiation on human tissue. Qubic wants to improve these systems so that they are more precise, and, above all, less intense in terms of microwave radiation. “Our transmitter could decrease the radiation dose to have images as clear as those obtained with traditional technologies,” he confirms.

In addition, the quantum microwave transmitter that Qubic designs could be used in telemetry and remote sensing systems. “These systems can be used to detect objects that are smaller or further away, or that would be more difficult to detect due to conditions that aren’t favorable for standard systems.” This technology could notably be used for DND and civil aviation.

“Our transmitter could be used for advanced quantum communication systems. One could imagine a more robust microwave communication link at its interception and during data decrypting compared to messages sent by traditional communications. We’re not talking about quantum encryption here, but rather providing a quantum advantage to conventional protocols in order to make them more robust.” In other words, the quantum microwave transmitters could inspire new classical quantum-inspired protocols.

Next Steps for Qubic

“For the next year, we plan to improve the prototype that we have developed to date, in order to demonstrate its potential in a specific application.” In addition to developing a pre-commercial prototype, the company also wants to attract the attention of potential collaborators and investors to bring this technology to a more advanced level of maturity to carry out field tests.