Where we are with quantum computing

A lot has already been written about the burgeoning field of quantum technology, but a three-page "Field Guide to Quantum Tech" in the Business section of today's Globe and Mail is as good a summary as I have see of what quantum technology is, its promise and its challenges, and where we are with it (we, the World, and we, Canada). 

Thankfully, you don't need to know the details of quantum theory to understand its potential. Suffice it to say, quantum mechanics, the theory,  was developed in Europe in the 1920s, and it was so revolutionary that we are still trying to come to grips with it a century later. Despite its difficult concepts - Schrodinger's cat, spooky action at a distance, "if you think you understand quantum mechanics, you don't understand quantum mechanics", all that - it has proven to be a remarkably robust and comprehensive model of our real-world physical reality.

The main technology envisaged for quantum technology is quantum computing. At its simplest, while a conventional computer uses billions of microelectronic switches to manipulate the 1s and 0s ("bits") that computers use for even their most complex operations, a quantum computer can take advantage of "qubits", which may be in the form of tiny superconducting circuits, ions trapped in electromagnetic fields, or beams of light orientated in different ways. What makes them special, though, is that, according to quantum theory, they can exist in two possible states (á la Schrodinger's cat), so that they can represent 1s and 0s, but also a mix of both. Under QM, particles can be in more than one place at the same time, and can act as though they are connected even when separated by large distances.

When many qubits are linked together, they can make quantum computers incredibly fast, capable of calculations that would take conventional computers literally millions of years to complete. Not all computer tasks can be accelerated in this way, but potential applications include cryptography (the current model of RSA cryptography, derived by multiplying together two massive prime numbers, would be child's play for a quantum computer - that's also part of the challenge it represents), but also modelling financial risks, optimizing traffic flow or factory production lines, simulating the behaviour of molecules to discover new medicines or better batteries, unspecified military applications, and many other things we probably haven't even thought of yet.

That, at least, is the promise. However, qubits are hard to work with. They typically have to be isolated from the slightest disturbance, often in cryogenic facilities to minimize vibrations and maintain them at temperatures colder than deep space. In order to be "fault-tolerant", quantum systems need to dedicate many more (orders of magnitude more) qubits to protecting and keeping a check on those doing the actual calculating.

Challenges notwithstanding, many, even most, countries are ploughing oodles of money into quantum research (China, of course, is way out in front), and many important breakthroughs have already been achieved. Big hitters like IBM, Google, Microsoft, Amazon and Nvidia are investing heavily, although new discoveries (quantum leaps?) are just as likely to come from startups like Quantinuum, IonQ, PsiQuantum and Rigetti Computing in the USA, Photonics, Two Small Fish Ventures, D-Wave Quantum and Xanadu in Canada, or any number of lavishly state-funded outfits in China.

Either way, quantum computers are currently still far from operating at a commercial scale. We may be 5-10 years away from that, or it may be decades. It's not clear when quantum tech might yield big returns, or if it EVER will. A US government competition aims to determine if reliable and cost-effective quantum computers can be developed by 2033, which is seen as a moderately ambitious date (although don't be surprised if that competition gets cancelled by the anti-science Trump administration).

Canada is considered a reasonably major player globally, even if the financial investment in the country is small compared to players like Japan, Britain, USA, Germany, and of course China, whose quantum research and commercialization commitments almost matches the rest of the world combined. Within Canada, quantum research is mainly located in hotspots like the Kitchener-Waterloo- Cambridge triangle in Ontario, British Columbia's Lower Mainland, the University of Sherbrooke in Quebec, and the university of Calgary in Alberta.

Even if AI continues to develop to the extent that it too can immensely speed up numerical calculations and simulations, as some suggest, quantum computers can't be ignored, even if only because they have to potntial to render conventional cybersecurity obsolete. Some warn that encrypted data is already being harvested by nefarious agents for later unlocking by quantum computers.

And computing is not the only application the quantum revolution is affecting: the quantum sensing sector is already up and running. For example, quantum effects can be used to improve our measurement and modelling of the Earth's magnetic field, which is crucially used by navigation systems and smartphones. 

Quantum information systems are also already in use for communication and surveillance. For example, there is a form of quantum radar that can spot interlopers without revealing its own presence like conventional radar systems do. Countries across the world are exploring other military potentials for quantum tech.

Quantum stocks took off in 2024, thanks to some high-profile advances in the technology, and many private investors are keen to get in early for the Next Big Thing. In fact, as happened with AI, some analysts are warning that we are probably already in bubble territory, as people are investing on hype alone, without a deep understanding of the technology involved and its potential pitfalls.

We are still coming to grips with artificial intelligence (AI), learning what it can do, dealing with its abuse. It seems a stretch to be thinking about quantum technology too. But it is coming, either slowly or all of a sudden, and we need to be ready for it.