A quantum computing startup tries to live up to the hype

Bloomberg

Few corners of the tech industry are as tantalising or complex as quantum computing. For years evangelists have promised machines capable of breaking the most impenetrable coded messages, unlocking the secret properties of the physical world and putting supercomputers to shame.
But Rigetti Computing, one of the most prominent and well-funded startups in the field, would just like to lower everyone’s expectations.
Right now, Rigetti’s challenge for itself is this: Can it solve one, single problem with a quantum computer that a conventional machine cannot? Even if it just meant answering a question more quickly or cheaply than a supercomputer, the team of physicists and mathematicians at the startup’s Berkeley, California, office would be overjoyed.
So far, no such luck. Today, your laptop can solve pretty much everything one of the startup’s quantum computers can do, just as quickly. The conundrum isn’t Rigetti’s alone. Neither IBM nor Google, which boast more powerful quantum computers, have said they’ve achieved “quantum advantage.” The ominous-sounding term refers to the theoretical moment when a quantum computer can do something more effectively than a traditional computer. It’s the industry’s equivalent of a singularity-esque breakthrough moment but even more nerdy and obscure.
“Right now, what we’re focussed on is the pursuit of quantum advantage,” said Chad Rigetti, the company’s eponymous founder.
Rigetti, the man, has spent his entire adult life fixated on a still-unrealised computational theory. After spending seven years earning a Ph.D. in applied physics from Yale University in 2009, he toiled away for a brief time as a researcher in International Business Machines Corp.’s quantum computing group. He started Rigetti Computing in 2013 at the age of 34.
Rigetti & Co., the company’s corporate name, has come a long way by startup standards. It employs former top researchers from NASA, Raytheon Co. and the universities of Berkeley, Stanford and his alma mater. The company built its own quantum computer, without access to the multibillion-dollar R&D budgets of the other companies investing in this effort. But it does have $119 million, more than half of which came in a previously unreported venture capital deal late last year. Rigetti chose to keep the investment quiet until to avoid further heightening expectations.
Now Rigetti, both the man and the company, thinks there may actually be something to brag about—despite the myriad issues that, as he is quick to point out, could still go wrong. The startup has designed a microchip for quantum computers that would have more than six times as many qubits—the basic measure of quantum computing horsepower—as Rigetti’s current machines. That would be more powerful than IBM’s 50-qubit computer and more powerful than Google’s 72-qubit machine. Rigetti is hoping to build a functioning computer with 128 qubits in the next 12 months. If successful, it could be the world’s most powerful quantum computer and just might have a chance of outpacing traditional supercomputers. “We’re making very fast, or exponential, progress on all these different fronts,” said Rigetti. “It’s all moving toward a supernova moment, and that is quantum advantage.”
Quantum computers are, however, far more prone to errors than binary machines. Instead of using electric signals to generate a series of zeros and ones like a conventional computer, quantum computers rely on the real-world, mechanical behaviour of photons, which are packets of microwave energy.