Bragging rights in quantum computing, like quantum mechanics itself, can get fuzzy. Take today’s claim from IonQ that it’s creating “the world’s most powerful quantum computer.”
To back up that claim, IonQ is turning to a metric known as quantum volume. That’s a multidimensional yardstick that combines stats ranging from the number of quantum bits (a.k.a. qubits) in a computer to the system’s error rate and cross-qubit connectivity.
In today’s news release, IonQ says its next-generation system will feature 32 “perfect” qubits with low gate errors, penciling out to a quantum volume value in excess of 4 million.
Taken at face value, that would take some of the steam out of this week’s announcement by Honeywell that its quantum computing system achieved a quantum volume of 128. Which took some of the steam out of IBM’s announcement in August that it reached a quantum volume of 64. And IBM is the company that came up with the metric.
The numbers game highlights the fact that the competition in quantum computing is just getting started, more than two decades after computer scientists laid out the theoretical foundations for the field.
Under the best of circumstances, quantum computing is hard to wrap your brain around. Rather than dealing with the cold, hard ones and zeroes of classical computing, the quantum paradigm relies on qubits that can represent multiple values at the same time.
The approach is particularly well-suited for solving problems ranging from breaking (or protecting) cryptographic codes, to formulating the molecular structures for new materials and medicines, to optimizing complex systems such as traffic patterns and financial markets.
Players in the quantum computing game include heavy-hitters such as IBM, Google and Honeywell — as well as startups such as Maryland-based IonQ, California-based Rigetti and B.C.-based D-Wave Systems.
Different approaches are being used. IBM, Google and Rigetti are focusing on superconducting logic gates; IonQ uses trapped-ion technology; and D-Wave relies on quantum annealing.
The important thing to keep in mind is that different technologies from different providers (including IonQ, Rigetti and D-Wave) are being offered on the quantum cloud platforms offered by Amazon and Microsoft. IBM and Google, meanwhile, provide their quantum tools as options on their own cloud computing platforms.
Developers who want to make use of quantum data processing aren’t likely to go out and buy a dedicated quantum computer. They’re more likely to choose from the cloud platforms’ offerings — just as a traveler who wants to rent a snazzy car from Hertz or from Avis can go with a Corvette or a Mustang.
That’s where metrics make the difference. If you can show potential customers that your quantum machine has more horsepower, you’re likely to do better in an increasingly competitive market.
Last year, IBM’s 53-qubit computer was touted as the world’s most powerful quantum processor, while Google claimed “quantum supremacy” with its own 54-qubit machine. And the ante is repeatedly being upped: Last month, IBM said it would pass the 1,000-qubit mark in 2023 and aim for a million-qubit computer over the longer term.
In contrast, IonQ emphasizes qubit quality over quantity. “We’re not going to throw a million qubits on the table unless we can do millions of operations,” co-founder and chief scientist Chris Monroe told me last December.
Peter Chapman, the former Amazon exec who now serves as IonQ’s CEO and president, said quantum computing should prove its worth well before the million-qubit mark.
“In a single generation of hardware, we went from 11 to 32 qubits, and more importantly, improved the fidelity required to use all 32 qubits,” Peter Chapman, the former Amazon exec who now serves as IonQ’s CEO and president, said in today’s news release.
“Depending on the application, customers will need somewhere between 80 and 150 very high-fidelity qubits and logic gates to see quantum advantage,” Chapman said. “Our goal is to double or more the number of qubits each year.”
IonQ’s 32-qubit hardware will be rolled out initially as a private beta, and then will be made commercially available via Amazon Braket and Microsoft Azure Quantum.
As we await the next raise in the numbers game, it might be a good idea to set up a trusted authority to take charge of the standards and benchmarking process for quantum computing — similar to how the TOP500 has the final word on which supercomputers lead the pack.
Such an authority could definitively determine who has the world’s most powerful quantum computer. Or would that violate the weird rules of quantum indeterminacy?
Update for 3:35 p.m. PT Oct. 5: We’ve added more precise language and links to describe the distinctions between different types of quantum computing technology.
