Ontario Innovators: A quantum leap in computer technology
Q&A: University of Waterloo’s David Cory on a new generation of computers that could help scientists understand the nature of the universe and custom-design new materials
Quantum computers are difficult to understand — probably because they rely on the principles of quantum mechanics, a branch of physics that is excruciatingly confusing to almost anyone who isn’t a physicist.
Prime Minister Justin Trudeau has come about as close as anyone to an explanation of quantum computers that a non-scientist can understand. But it’s arguably less important to understand how quantum computers would work than why so many people across the world are trying to build them.
University of Waterloo recently received $76 million from the federal government to research the application of quantum principles to advance computing, communications and sensor technology. According to David Cory, head of the university’s Transformative Quantum Technologies program, quantum computers could be, well, transformative.
What are some things that a quantum computer would be able to do that a regular computer can’t?
Let me preface this by saying there are many things that a quantum computer doesn’t improve [compared to a classical computer]. But the fun thing is of course to talk about what it does improve. If I want to search an unordered list, for instance, I can do that more efficiently with a quantum computer.
The old example would be to say if I had a phone number and I wanted to find [the corresponding] name I would have had to leaf through a phone book. A quantum computer could do that [much faster] than a classical computer would do it. The quantum computer can take logarithms exponentially faster, which is how we break the [computer security] encryption schemes that we use today.
For a quantum computer, today’s most exciting thing is that it allows us to simulate, understand and design better materials. We’re trying to find materials that are better at energy harvesting. We’re trying to find materials that are better at energy transmission. We’re trying to find materials that allow us to compute based upon the magnetic state of electrons rather than their charge. If we could do that, it would increase the efficiency of your laptop by nearly a factor of 1,000.
So quantum computers could help us design more efficient products that reduce our energy footprint?
That’s right. New materials have great impact. Today’s new materials are often discovered by accident. And it would be lovely to turn the corner and have new materials by design. And quantum mechanics gives the promise of that.
Another avenue of research is quantum communication. How would that be different from conventional communication?
What quantum communication does is it gives you the ability to hide a secret. So imagine that you wanted to buy some information from some website. Using quantum communication you would be able to purchase content. The person that owns the content would know that you purchased the content, would know that you are happy with the content, would know that you had paid for the content — but would have no idea and no way of ever knowing what content you actually bought. It gives back an ability to individuals to control their information.
What do you hope your team will accomplish in the next 10 years?
A few things. One, it will have a 50- to 100-qubit quantum computer: [sufficient calculating power to] be able to use it to explore physics, new materials and use it to start down this path of engineering the next generation of the quantum computer. We will have quantum sensors that society will be using. They’ll use them in health, they’ll use them in medicine, they’ll use them in exploration. [A quibit is the quantum equivalent of a classical bit.]
There are many people that are trying to reach this next level of quantum computing. The 50- to 100- qubit level you’ve mentioned — what would it mean if your team was the first?
Science proceeds by the world being able to do more. Science doesn’t proceed by one lab being first. I know other scientists like this vision that we’re racing and there’s some national pride on the line. It doesn’t work for me. I want to see science progress. I want to see all of us being able to do more.
This interview has been edited for length and clarity.