QUANTUM computing has hit the big time. In a paper leaked online just over a month ago, Google said it had performed the first quantum computation that was beyond an ordinary machine, a milestone known as quantum supremacy. Since then, the headlines have been breathless.
Google鈥檚 achievement has been heralded as doing everything from breaking the internet to solving the climate crisis. But let鈥檚 stop and breathe. Quantum computing鈥檚 true potential is still decades away and hitting peak quantum now may scupper the whole endeavour.
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Part of the excitement came from the secretive nature of the reveal. Despite the leak, Google refused to comment until the paper鈥檚 official publication in Nature last week. This led to a build-up of buzz usually reserved for the likes of a new iPhone.
In truth, the hype has been growing for more than a decade. For most of that time, quantum computing has felt as elusive as other forever-around-the-corner tech, such as nuclear fusion. The media and industry have played up its virtually limitless potential: these devices will be able to model new drugs and materials, simulate the climate and financial systems in unprecedented detail, break cryptography, and much more.
鈥淭he real excitement about quantum is that the universe fundamentally works in a quantum way, so you will be able to understand nature better,鈥� Google鈥檚 CEO, Sundar Pichai, told MIT Technology Review.
Well, not with this computer. From an engineering perspective, the result is impressive. Quantum systems are hard to control and manipulate even for a fraction of a second. But Google鈥檚 quantum device does nothing useful.
John Preskill at the California Institute of Technology, who coined the term quantum supremacy, has pointed out that Google deliberately chose a narrow task that a quantum computer would be good at and a classical computer is bad at.
The 鈥渟upremacy鈥� part also suggests that quantum computers outperform classical ones across the board, which isn鈥檛 true. Classical computers are likely to remain better than quantum machines for most everyday tasks. Sorry, but you won鈥檛 get a quantum laptop.
Pichai has compared his company鈥檚 achievement to the Wright brothers鈥� first flight 鈥� an apt analogy. Orville Wright flew for 12 seconds, which was a stunning proof of concept but little more. It took years of work before there were reliable, long-distance flights, and decades more before passenger jets made a difference to the average person鈥檚 life.
Pichai also said that he thinks quantum computing will be as important as artificial intelligence, which may be the better comparison. Wild claims about AI have brought disappointments. There is even a name for it: AI winter. When reality fails to live up to people鈥檚 expectations, funding dries up and researchers move on.
To avoid a quantum winter, we should dial down the hype. A lot of companies are chasing a quantum pay-off, but it is a gamble. Can we make chips that scale up and are accurate enough to do anything useful? If practical devices prove elusive, will firms keep at it or veer off to easier wins? Google in particular has a reputation for killing projects it loses interest in.
It has taken Google 13 years to get this far. Without a profitable device, research could dry up. It happened with the Apollo programme. It has happened at times with AI.
Ultimately, quantum supremacy is a waypoint, not the destination. It is quantum advantage 鈥� showing that computers can do something useful that others cannot 鈥� that will be truly exciting. Just don鈥檛 hold your breath.
