What can quantum computing do for us?

Vancouver-based 1QBit is one of the World Economic Forum’s 2015 class of Technology Pioneers. The company creates software for quantum processors that can address real-world challenges involving difficult computational problems. Co-founders Landon Downs and Andrew Fursman discuss what quantum computing can do now and where it is headed.

Can you briefly explain the background of quantum computing?

People first started thinking in the 1980s that you could build a computer that uses the quantum properties of matter to perform calculations much more quickly than traditional computers. All computers today work with “bits”, which are either on or off. But a quantum equivalent of a bit, a “qubit”, could be simultaneously on and off, because of the peculiar way matter behaves at the quantum level. Physicists like Richard Feynman and David Deutsch theorized that, if you could replace a computer’s bits with qubits, this behaviour could be harnessed to make computation orders of magnitude quicker.

However, getting from theory to practice proved depressingly difficult: it took years of research to get from creating one qubit up to a system using three qubits. And computers have billions of bits. So people started to move away from the ambition of using qubits to build a universal computer, and instead focus on whether there were other ways to use quantum effects to perform a more limited range of specific types of computation.

It’s like the difference between calculators and computers. If you’re old enough to remember pocket calculators, they couldn’t do everything your smartphone can do now – but they could do a limited number of things very well, far better than the alternative of working out with a pencil and paper. That’s where we are now – “quantum calculator” would probably be a better description than “quantum computer” for the processor on which our software runs. Its domains are relatively narrow, but within those domains it enables exciting applications.

What kinds of problems are susceptible to a quantum processing approach?

In general, problems that involve looking for the best solutions among a vast array of possible options. There are two ways you can approach this kind of problem. One is to consider all the options in turn, and see which one is best. But pretty quickly that becomes impractical. If you imagine just 250 questions that can be answered with either yes or no, you already have more possible combinations than there are atoms in the observable universe.

So the alternative is to use heuristics – tricks and techniques that have evolved over hundreds of years for situations when you’re not realistically hoping to find the best possible answer, but an acceptably good answer in an acceptably short time frame. The quantum behaviour of matter allows these processors to quickly arrive at optimal answers through a process known as quantum annealing. The aim is to get answers that are closer to what you’d get from an exhaustive search, in the same timescale it takes to run heuristics.

What are some real-world examples of applications that could use this power?

One example of software we recently built and patented is a tool to compare multidimensional structures and decide which are most similar to each other. Among the likely applications is drug development – if you have a completely new molecule and want to predict what effect it will have on the body, one way to do so is to compare it to a database of molecules with known effects. Is it more similar to a molecule that’s known to cure cancer or to cause heart disease?

But you could just as well apply this software to anything that can be conceived of as a collection of nodes and edges – what in mathematics are known as graphs. In finance, for example, you could represent various possible portfolios as graphs and compare them. Computational finance is an area we’re working in because there are obvious benefits to reaching better answers in limited time frames about, say, the optimal combination of financial instruments for a portfolio.

Graph comparison is only one of a number of software tools we are developing that can run on today’s quantum processors. And as those processors get larger and larger chips, the applications we build on these kernels of software will become more and more powerful.

What quantum processor does your software run on?

A system produced by our partner D-Wave. To get quantum behaviour from the qubits, the processors are in a vacuum, shielded from the Earth’s magnetic field and supercooled close to absolute zero. In terms of the scale of equipment required to do this, you can compare it to the first mainframe computers from the 1960s rather than the personal computers of today.

Is the D-Wave the only quantum processor or are there others?

D-Wave is currently the only commercial entity producing a quantum processor you can buy. But there’s nice work being done by lots of groups – in start-ups, academia and tech giants like Google, Microsoft and IBM. Some of this work is being done on super-conducting systems like the D-Wave, and some is much more exotic and experimental.

To what extent are these different groups able to keep on top of the work the others are doing?

Research in academia constantly gets published, and we’re involved in various working groups – both formal and informal – including a D-Wave users group, which includes NASA, Lockheed Martin, Google and the Universities Space Research Association. We try to keep abreast of what each other are doing, guide each other and understand what looks promising. There’s not much competitiveness, as we know that the more momentum the field itself generates, the better it is for all of us.

Is it possible to predict where quantum computing will be in one, five, ten or twenty years?

Both the short and the long time frame are easier to answer with confidence. There’s been a fairly consistent trend of the number of qubits doubling each year, and D-Wave has just announced the release of the first processor that has more than 1,000 qubits. So, in a year, we’d expect to have a processor with over 2,000 qubits. And almost everyone agrees that, in 20 years, we will have developed the more general purpose, universal quantum computers envisaged by the likes of Richard Feynman back in the 1980s.

What’s uncertain is what happens in the intermediate time frames, because there are a million different paths we could take to get there from here. Our prediction ‒ and certainly our hope ‒ is that progress is driven by broadening access to the technology. In the future, we want to build software for other developers to build on, enabling people to play around with quantum processing in the same way they now play around with Android phones. When that happens, we believe we will see all kinds of exciting new applications develop.

Full details on all of the Technology Pioneers 2015 can be found here. 

Authors: Landon Downs and Andrew Fursman, Co-Founders, 1QBit

Image: A silicon wafer is pictured during the media presentation of the Guardian Angels project in one of the low particle pollution nanofabrication clean rooms of the Swiss Federal Institute of Technology (EPFL) in Ecublens, near Lausanne May 16, 2011.REUTERS/Valentin Flauraud