thousand years and your conventional computer still couldn’t do what a quantum computer will do,” enthuses Hensinger, who, worryingly for laypeople, calls it all “mind-boggling”. The upshot could be profound, for example, in the rapid development of new materials or of new drugs; in machine learning and AI; or, as Hensinger has demonstrated in a recent paper, in advancing high nitrogen fertilizer production, which could, in turn, radically improve global food supply. It’s a small wonder then that the world outside of quantum physics – chemical and pharmaceutical industries, banking and investing, security and intelligence – are quickly waking up to this potential. This year IonQ became the first dedicated quantum computer developer to be listed on the New York Stock Exchange; it quickly gained a market capitalization of $3 billion. “I’m not sure how much of the public understands the exoticism behind any approach to quantum computing, or whether it really needs to, I mean, how many of us know how our cellphones work?” asks Christopher Monroe, atomic physicist and IonQ’s co-founder. “But the listing does make a statement that there’s an appetite for investing in quantum computing now, that there’s an expectation that it will produce value.” “It’s been a victory story for universities being allowed to do fundamental research, in the same way that understanding nuclear physics was purely academic before applications were found,” explains Wim van Dam, professor of computer science at the University of California, Santa Barbara, and one of the pioneer thinkers 25 years ago in the then decidedly esoteric field of quantum computing. “Attitudes are changing. It’s rather like people talking of building a big bridge - you can hear it described, or see some drawings, but it only really becomes understandable when you see an architect’s model. For people outside of the field of quantum mechanics it was all ‘blah blah equations blah blah’. Now it’s starting to feel real.” That said, we’re still at the dawn of this quantum age. Hensinger compares it to being back in the 1940s with conventional computers – long established in theory, but only then finding the first practical applications, notably in the breaking of the German Enigma code. “And much as then, people had no idea that computers might become what they are today, it would be a mistake to assume we will know what quantum computing will be capable of for decades,” he stresses. Of course, there remain major challenges: there’s what’s called ‘noise’, those environmental factors like vibrations and electromagnetic waves, that a quantum computers’ delicate state doesn’t like at all. And, as Hensinger notes, “you can’t just run Windows on a quantum computer.” Finessing
“ I’m not sure how much of the public understands the exoticism behind quantum computing, or whether it really needs to.”
the software’s bespoke algorithms is, for instance, as big a challenge as developing the hardware. And yet, recent years have seen massive leaps forward in bringing practicable quantum computers to life, with the development work of a handful of leaders in the field, each tackling the various operational hurdles that need to be overcome for quantum computing to necessarily scale up. Hensinger’s Ion Quantum Technology Group, for example, has devised a way of holding those qubits stably in place not by use of lasers – the ‘standard’ if less mature approach today – but with microwaves. His company, which also has a means of realizing a fully modular quantum computer in the pipeline, now has serious venture capital funding. Likewise, Rigetti, a start-up in Berkeley, has worked out how to forcibly reset qubits for re-use some 30 times faster, thus removing valuable latency from the system, while IonQ has shown a path away from using what are, essentially, pimped-up solid state platforms for quantum computing (with all of the variations that can upset quantum processes) towards what is known as a ‘trapped ion’ system; it uses individual, perfectly replicable fundamental particles assembled by nature. If most quantum computing hardware requires massively expensive super-cooling to almost absolute zero, IonQ’s can be operated at room temperature. “But what’s important is that really none of the hurdles are problems in physics, so much as problems in engineering, albeit serious ones,” says Monroe. “And [in the end] the different approaches to quantum computing will probably coalesce, as happened in the development of conventional computers.” When that occurs, who knows what quantum leaps might follow? “Whenever we get something fundamentally new in processing information – the printing press, connecting computers online, etc. – it’s always revolutionary,” says Van Dam, who predicts a major breakthrough within five years. “And given how ubiquitous processing information is now, if quantum computing can fundamentally change that, the consequences will be considerable. We just don’t know what those consequences will be yet. It’s going to take a while, but they’re going to be big.”
