New funding from NSERC and UK Research and Innovation (UKRI) will advance several U of T Engineering projects related to quantum communication networks, quantum computing and more. 

Professor Li Qian (ECE) is a key principal investigator on three of the newly funded projects. Her overarching goal is to make quantum communication more practical and accessible.  

“Whether it’s about protecting banking information or safeguarding the signals that control critical infrastructure, there is a lot of interest in secure communication these days,” says Qian. 

“In quantum communication, we leverage phenomena from quantum physics to ensure that nobody can listen in or alter the message. But establishing quantum links over very large distances poses special challenges, and that’s particularly relevant for a geographically large country like Canada.” 

Establishing a quantum link typically involves creating photons that are interrelated via a quantum phenomenon known as entanglement. 

Once two or more photons are entangled, their quantum properties match in a way that can’t be altered. Measuring or attempting to copy one of the photons instantly affects the photon as well as its entangled partner, rendering any attempt to listen in on the signal detectable. 

But sending entangled photons through traditional optical communications networks is far from straightforward. 

“Optical fibres are the best technology we know of for long-distance communication, because the losses are very low,” says Qian. 

“But at the same time, the losses are not zero, so by the time you have gone a hundred kilometres, you’ve lost 99% of the photons. 

“With classical signals, that’s not a problem, because you can add amplifiers along the way that boost the signal as it degrades. But if you’re only sending single photons, which is the case in quantum communication, that is very hard to do.” 

Qian is an expert in creating sources of entangled and hyperentangled photons. Two of the newly-funded projects involve collaborations with Canadian researchers and companies to create long-distance quantum links for secure communications, particularly in the area of defence. 

In the UKRI project, she is working with researchers at the University of Bristol to study how principles and paradigms from classical optical networks can be adapted for quantum networks. 

“My collaborators know a lot about how to package signals, or how to dynamically reconfigure the network to deal with high-traffic situations,” says Qian. 

“We are looking at how you approach these challenges differently once you start sending entangled photons.” 

Qian is also part of a collaboration between Canadian and European researchers known as HyperSpace, which aims to use satellites to establish trans-continental quantum networks. 

“As in any industry, customers want a range of solutions to meet their various needs,” says Qian. 

“If we can reduce its cost, expand its range and enhance its reliability, we can make secure quantum communication a practical reality for many different kinds of users.” 

Qian’s projects are among several across U of T Engineering that will share more than $7.5 million in funding from several NSERC Alliance programs, as well as $800,000 more from NSERC and UKRI via the UK-Canada Quantum for Science Research Collaboration. 

The full list of U of T Engineering projects and principal investigators includes: 

• Advanced QUAntum applications via complex states in integrated and meta optics (AQUA) — Stewart Aitchison (ECE) 

• Dynamic metropolitan-scale entanglement distribution networks and beyond — Li Qian (ECE) 

• QuantaMole: Consortium on quantum molecular technologies — Amr Helmy (ECE) and Alan Aspuru-Guzik (Department of Chemistry) 

• Quantum dot photonics for large-scaled Entanglement — Li Qian (ECE) 

• Quantum software centre — Hans-Arno Jacobsen (ECE) 

• Twin Fields: From secure quantum communication to quantum sensing networks — Li Qian (ECE)