Quantum computing is booming, but is it a bubble? At a gathering of experts on this technology in California last week, nobody seemed to know how, or even if, it will turn out to be useful. The race for quantum supremacy may be over, but the race for a useful quantum computer is still on.
Quantum supremacy refers to the point at which a quantum computer can solve a problem that no classical computer could in a reasonable amount of time – a feat Google said it had achieved in October with an algorithm proving that strings of bits were random.
While that problem has no real practical value, it was a great demonstration that quantum computers can work. What most people are still waiting for is quantum advantage – the point at which these computers are better than classical computers for performing a useful task. A mix of researchers and investors in quantum computing gathered in December at the Q2B Practical Quantum Computing conference in San Jose, California, to discuss when and how that might happen.
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The conference has more than doubled in size since its first event three years ago, now attracting more than 500 people. Announcements during the gathering of link-ups between quantum computing companies and firms like Ford and investment bank Goldman Sachs also point to rapidly growing interest in the field in the wider world.
But listening to the speakers, it wasn’t clear what anyone expects from this boom. Many discussed how quantum computers are expected to be able to simulate molecules and chemistry better than classical machines, which could result in new materials and drugs. Others spoke of optimising stock portfolios and other big-data problems in the financial sector. Whether we will be able to build a quantum computer that is actually significantly better than a classical computer at doing any of that is still up in the air.
That isn’t deterring investors from jumping on the bandwagon though. “If you wait for żěè¶ĚĘÓƵ or someone to say we’re now at quantum advantage before you start looking into quantum computing, it could take two years before you’re ready to take advantage of it,” says Bill Hartnett at investment bank Citi. “There’s a sort of insurance aspect to it.”
Oliver Wick, who leads BMW’s quantum computer group, has a similar view. “It’s like a 100-metre race. We have to get ready, because if we aren’t ready for the race, then when it begins we will have a hard time getting started,” he says. “I don’t have a business case, it’s just about readiness.”
But researchers at Q2B also spoke about avoiding hype and the idea that quantum computing will solve every type of computing problem. “Quantum computers are not general-purpose devices,” said IBM’s Katie Pizzolato. “They will always be best when they are applied to the right problems.”
For now, though, it isn’t clear what the right problems will be. “It may be that we’ll find useful applications, but we can’t guarantee it,” said John Preskill at the California Institute of Technology. “I think we have reason to be optimistic about quantum technology having a transformative effect on society eventually, but that may take decades of hard work and investment.”
How long it takes will depend on whether the current appetite for funding quantum computing holds up. “There is a real risk of running out of goodwill and funding in the mean time,” said Google’s Ryan Babbush. If that happens, we may never learn what quantum computing is really good for.
