Last May, I had a discussion with Peter Chapman, CEO of IonQ, a start-up quantum computing company. Before coming to IonQ, Chapman worked for Amazon, where he was responsible for all the technical complexities of Amazon Prime. IonQ had accomplished a lot in the twelve months that Chapman had been at the helm, so I was looking forward to talking to him.
My biggest surprise during that discussion was that IonQ was simultaneously working on its next three generations of its trapped-ion quantum computers – 5th, 6th, and 7th generations.
In a recent follow-up with Chapman, including Chris Monroe, IonQ’s Co-founder and Chief Scientist, we discussed IonQ’s release of its 5th generation quantum hardware. Keep in mind that the 6th and 7th generations are still in development. Chapman said that each generation would be smaller and more powerful than its predecessor when released. Although he didn’t mention it, I wouldn’t be surprised if Chapman’s team hasn’t already begun work on IonQ’s 8th generation processor.
Features of IonQ’s new 5th generation quantum computer
A qubit is the fundamental unit of information in a quantum computer. A classical computer bit can only be a one or zero. A qubit can also exist as a one or zero, but when in a quantum state, it can be a superposition of both values. Ion says its newest quantum hardware has 32 ion qubits in its latest release, almost tripling the 11 qubits in its previous quantum computer.
Robert Niffenegger, a Ph.D. and a member of the Trapped Ion and Photonics group at MIT Lincoln Laboratory, said he wasn’t surprised at the large jump in the number of qubits. “Honestly, I think a lot of people were just holding their breath until they [IonQ] announced. They’ve published papers on ways of cooling chains of 20 ions that have hinted that they had much more than the 11 ions they put on the cloud – the question was just how many?”
The new quantum computer also includes another new development. It allows random access on all-to-all gate operations. This improvement will allow a more efficient software compilation of applications. According to Chris Monroe, IonQ is also working on a future capability similar to Honeywell’s mid-circuit measurement and reuse.
Our inability to correct qubit errors is one of the reasons we cannot build quantum computers larger than a few hundred qubits. Finding a solution to error correction is important to the future of quantum computing. That’s why it has the attention of many researchers. Some believe that as many as one thousand qubits might be necessary to correct one qubit error. Such a requirement could result in a quantum machine the size of a football field. In its new processor, IonQ incorporated a new error correction code that it says only uses 13 qubits. Monroe said that while the code didn’t play a major role in this announcement, it will be useful in later versions as qubits are scaled up.
A quantum leap in quantum volume
The most startling part of IonQ’s new announcement was the claimed enormity of its new computer’s quantum volume.
Quantum volume is a hardware-agnostic performance measurement for gate-based quantum computers. IBM developed it in 2017. QV considers such things as the number of qubits, connectivity of the qubits, gate fidelity, cross talk, circuit compiler efficiency, and more. In other words, it takes more than just adding qubits to increase the quantum volume: the larger the QV, the more powerful the machine.
Quantum volume normally requires running algorithms with quantum volume circuits. Before IonQ’s announcement, Honeywell’s 7-qubit ion-trap quantum computer had the industry’s highest published quantum volume of 128. IBM had the next highest QV of 64 with its 27-qubit superconducting quantum machine.
It’s the accepted norm for quantum scientists to publish scientific proof of new quantum hardware, software, and theories. Honeywell documented its QV 128 with some details on its website. And IBM published technical information about how it achieved QV 64 in a research paper. In this case, rather than running quantum volume circuits with publishable results, IonQ resorted to calculating the quantum volume. Its calculated QV was a staggering 4 million, and that only considered 22 of its available 32 qubits. That’s almost 65,000 times greater than the highest published QV.
Jungsang Kim, co-founder and Chief Technology Officer, explained why IonQ decided to calculate quantum volume rather than running quantum volume algorithms: “We have a temp[orary] solution for some of the optics that allowed us to have confidence in the gate fidelity that allowed us to calculate approximate QV. As we speak, we are putting in the final production optics and will be able to get a final number on the machine. The four million number required only 22 qubits with 99.9% fidelity, and so we expect the final QV to only be limited by the gate fidelity rather than number of qubits.”
Had all 32 qubits been used in IonQ’s calculation instead of just 22 qubits, the claimed, expected quantum volume would have exploded from 4 million to a quantum volume of over 4 billion. That would be 31 million times greater than any quantum volume ever published.
Niffenegger believes that the gate fidelity wasn’t high enough to use all 32 qubits. Another quantum theorist that I spoke to said that two-qubit gates would need nothing less than 99.96% fidelity to achieve a quantum volume of that magnitude.
It will be settled, because according to Chris Monroe IonQ will soon publish a research paper on the new processor.
As mentioned, IBM and Honeywell have each previously published its respective quantum volume. With that in mind, I asked each company for its reaction to the IonQ announcement.
IBM provided this response: ” The Quantum industry announcements this week are interesting. Certainly, the ion trap-based firms are increasing their competitive intensity in that segment of the market. The growing use of Quantum Volume as a metric is also worth noting. That said, for further comment, we will wait until we see the associated research published and learn more about the details of these news announcements. The IBM Quantum team is confident in our roadmap announcement earlier this month. We have published our results and innovations for review and discussion with the scientific and analyst community. Our progress and innovations are demonstrated and available on the IBM Cloud now. To serve our rapidly growing base of over 260,000 registered users, we remain focused on accelerating growth in real usage and continuing to drive up circuit fidelity and overall circuit volume.”
Honeywell’s CEO, Tony Uttley, also weighed in on the announcement. “IonQ’s announcement is good for the advancement of quantum computing in general. The fact that you can make large increases in qubits like this is what makes trapped-ion such an exciting technology. It shows the power and future potential of the platform.”
Analyst notes and conclusions:
- IonQ’s announcement significantly advances quantum computing in general. Controlling 32 ions in a linear trap is no small scientific feat. IonQ’s goal is to double the number qubits each year. IonQ might need to add another quantum interconnected linear trap in the future.
- The release of IonQ’s generation 5 machine brings us another step closer to quantum advantage, a term that means quantum computers can outperform classical machines in certain use cases. Depending on the application, Peter Chapman believes that 80 to 150 very high fidelity qubits and logic gates might achieve quantum advantage.
- Not to diminish IonQ’s achievement, but because it is so impressive, I’m obligated to call a foul. The general scientific community commonly makes announcements before publishing a research paper. However, for many reasons, that’s not the norm in quantum research. A research paper is especially important if a benchmark claim exceeds its double-digit predecessors by a factor of 65,000. I don’t believe press release announcements on significant quantum achievements such as IonQ’s without proof helps to advance the field. It is easy to claim, but providing scientific evidence is much harder.
- It will be very interesting when IonQ makes the new machine available to researchers. A lot of people are curious what can be done with 32 ions. Expect to see early papers by financial institutions such as JP Morgan Chase.
- IonQ already has a presence on Amazon Braket and Microsoft Azure. I estimate that private betas using the new hardware will begin within a few months, and deployment on the cloud platforms will happen sometime in mid- to late-2021
- Government funding and private investment monies are available because the overall health of the quantum computing ecosystem is excellent. IBM recently released a detailed roadmap showing a development path leading to a million qubit superconducting quantum computer. Google hinted at a similar roadmap. Additionally, Honeywell uses its advanced QCCD trapped-ion architecture with several zones that have plenty of room for more ions. And, photonics and silicon are beginning to make progress.
Note: Moor Insights & Strategy writers and editors may have contributed to this article.