what’s next for quantum computing?

what’s next for quantum computing?

Quantum-computing companies have been grabbing headlines since Jensen Huang, chief executive of tech giant Nvidia, reportedly told market analysts on 7 January that he couldn’t see quantum computers becoming “truly useful” for another two decades. The day after, the share prices of firms IonQ, Quantum Computing, Rigetti Computing and D-Wave crashed — although they have since partially bounced back.

This stock-market volatility follows major ups and downs for these firms in recent years. In late 2024, their stocks reached record highs following announcements by Google in December, including that its Willow quantum chip had achieved a milestone in lowering the error rate of calculations, a breakthrough in the quest to build useful quantum computers. Quantum computing promises to harness quantum physics to perform some calculations — such as the details of chemical reactions, or finding the prime factors of large numbers — that would take a classical computer longer than the age of the Universe to complete.

Are these companies’ stocks as fragile as the quantum states of the qubits they are designing? And are the swings justified by technological and scientific breakthroughs — or setbacks?

Industry optimism

Global Quantum Intelligence (GQI), a company that tracks the quantum market, doesn’t think so. “Although the quantum technology has continued to make steady progress in 2024, and will continue to do so in 2025 and beyond, we feel the stock market has overreacted to all these announcements,” says Doug Finke, a computer scientist in Orange County, California, who is GQI’s chief content officer.

“The industry has kept up a steady pace of progress, and optimism prevails,” says Maria Schuld, a physicist who works for the quantum-computing start-up Xanadu and is based in Durban, South Africa.

To many observers, the biggest surprise was that Huang didn’t say anything that most quantum-computing specialists hadn’t been saying publicly for decades. Building a full-scale quantum computer is “a lot harder than people think”, says John Martinis, the physicist who led Google’s quantum-computing team during its 2019 breakthrough — the achievement of ‘quantum advantage’, or performing a calculation that is beyond the capabilities of any current classical computer. He has since left and co-founded a quantum-computing start-up called Qolab in Santa Barbara, California.

Perhaps one clear sign that the race is still in its early stages is that none of the many quantum-computer platforms — the methods used to physically embody qubits — has yet clearly pulled ahead of its competitors. “I would have thought we would have had a clear winner by now, but we don’t,” Scott Aaronson, a theoretical computer scientist at the University of Texas at Austin, told the Q2B24 conference in December.

Competing technologies

Two technologies are seen as leading the pack. The one favoured by Google, IBM, Rigetti and Qolab, among others, represents quantum states as currents in superconducting loops. The other, pushed by firms including IonQ, Quantinuum and Alpine Quantum Technologies, uses individual ions suspended in a vacuum. Quantum Computing, PsiQuantum and Xanadu, meanwhile, are aiming to do quantum computing with photons.

New entrants are joining the race all the time. These include Silicon Quantum Computing’s silicon quantum dots and QuEra’s neutral atoms. Further down the line, Microsoft is betting on ‘topological’ qubits, which have yet to be demonstrated in the laboratory but could bring substantial advantages by being less error-prone.

Nvidia CEO Jensen Huang gives the first Keynote speech of CES 2025 in Las Vegas.

Jensen Huang, chief executive of Nvidia, said this month that he couldn’t see quantum computers becoming “truly useful” for another two decades.Credit: Travis P Ball/Sipa USA via Alamy

Researchers say that each approach has pros and cons, and that all will require substantial improvements before these machines could start to fulfil some of the long-held expectations for quantum technology. Doing so will require improving the reliability of individual qubits, and packing in at least a million qubits into one machine. A crucial step is to combine several qubits into collective quantum states that are more resilient than are those in a single qubit, using methods researchers call quantum error correction. One result Google announced in December showed that adding more qubits improves error correction.

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