DARPA, the Defense Advanced Research Projects Agency, has announced that it has selected the companies that will receive funding under its Underexplored Systems for Utility-Scale Quantum Computing (US2QC) program.
The companies selected for US2QC are:
- Atom Computing — Atom is based in Berkeley, California and has an advanced research facility in Boulder, Colorado. In October 2021, Atom unveiled a gate-based 100-qubit quantum computer called Phoenix, which uses an optical array platform based on strontium neutral atom spin qubits. These qubits have an exceptionally long coherence time of about 40 seconds. A second generation machine with more qubits, higher fidelity and advanced features is expected to be announced soon.
- Microsoft — Microsoft’s quantum platform, which so far has no working prototype, is based on highly theoretical topological qubits and Majorana fermions. After early problems with misinterpretation of results, the company has restarted its topological research program. Microsoft recently announced progress and detected a topological gap, an important indicator that the research is on track.
- PsiQuantum — Based in Palo Alto, California, the company is developing a single photon-based quantum computer. Rather than developing intermediate qubit-sized processors, for its first release PsiQuantum is planning on a million-qubit processor. It is using Global Foundries for fabrication of its CMOS silicon processor.
Purposes of the US2QC program
DARPA is sponsoring the US2QC program to explore new ways to scale qubit count for larger systems, create additional layers of entanglement connectivity for faster performance and develop a broader set of quantum error correction algorithms for fault tolerance. Specifically, DARPA wants to determine if relatively new quantum technologies such as neutral atom, topological and photonics can be leveraged to develop a fault-tolerant quantum computer within ten years. Although the amount of funding wasn’t specified, I expect it will be enough to significantly move the needle for the corporate teams involved, given the program’s five-year span and DARPA’s $4.1 billion 2023 budget.
It is important for the United States to maintain its global lead in quantum computing and be the first to build a fault-tolerant quantum machine. In the DARPA press release, Joe Altepeter, US2QC program manager in DARPA’s Defense Sciences Office, helped explain why. He said: “Experts disagree on whether a utility-scale quantum computer based on conventional designs is still decades away or could be achieved much sooner. The goal of US2QC is to reduce the danger of strategic surprise from underexplored quantum computing systems. We put out a call last year saying that if anyone thought they had a truly revolutionary approach to building a useful quantum computer in the near future—less than 10 years—we wanted to hear from them. We offered to collaborate by funding additional experts to join their team and provide rigorous government verification and validation of their proposed solutions to determine its viability. The ultimate outcome of the program is a win-win—for U.S. commercial leadership in this strategically important technology area and for national security to avoid being surprised.”
Rob Hays, CEO and President of Atom Computing, explained the advantages for Atom in the DARPA program. “It’s almost like creating a parallel prototyping roadmap that accelerates the future relative to what we could do on our own without the DARPA partnership,” he said. “The partnership comes in the form of dollars to offset our internal costs, and it also provides access to experts from the Defense Department, academia and national labs to help direct us and provide feedback on our results. It’s very valuable and we’re very honored to be selected to help advance the state of the art.”
Why DARPA is involved with quantum computing
DARPA was created in 1958 by President Dwight Eisenhower as part of the United States Department of Defense. It was formed with the goal of preventing technological surprises from adversaries, such as when the Soviet Union launched Sputnik, the world’s first satellite, allowing it to gain a lead over the United States in space technology. DARPA’s mission is to invest in high-risk, high-reward research projects that have potential to revolutionize the military and civilian industries.
DARPA’s funding portfolio contains a wide range of research projects, from basic scientific studies to the development of advanced technologies like the Internet, GPS and autonomous vehicles. Besides quantum computing, DARPA continues to invest in emerging technologies such as artificial intelligence and bio-engineering.
Roadmap for the US2QC program
Moving from the architecture of today’s prototype quantum computers to a fault-tolerant architecture requires development of technologies and software that don’t yet exist. The DARPA program represents a five-year commitment of funds and resources by both DARPA and the companies participating in the US2QC program to address this challenge.
The program was designed with a clear understanding that it is a long-term effort. DARPA has also incorporated a flexible acquisition strategy to fund efforts that are mutually beneficial for both the U.S. Government and for companies that may already be expending significant resources to achieve rapid progress in quantum computing systems.
Phase 0: Each company must present a comprehensive plan for building a fault-tolerant quantum computer. The plan must include the components and subsystems, expected performance and strategies for mitigating technical risks. This plan for this phase should provide enough information to create a research and development roadmap for the prototype.
Phase 1: Using the information from Phase 0, the companies must design and construct a fault-tolerant prototype that meets the specifications outlined in the plan.
Phase 2: Each company will work with the government team to transition from today’s noisy intermediate-stage quantum (NISQ) designs to fault-tolerant designs and to ensure that the new components and subsystems meet the fault-tolerance specifications established in Phase 1. The final design for the prototype must incorporate the measured performance of these components and subsystems. The final machine will have all the elements needed to build a fault-tolerant system—likely not at full size initially, but capable of scaling up over time.
The need for the United States and its allies to achieve quantum fault-tolerance before their adversaries is widely acknowledged by experts. Three years ago, I wrote an article titled “Quantum USA Vs. Quantum China: The World’s Most Important Technology Race” highlighting the challenges and crucial matters involved. Although the challenges have changed and the funding has increased, those crucial matters remain unchanged.
Quantum computing players IBM and Rigetti (superconducting technology) and IonQ and Quantinuum (trapped-ion technology) were not chosen for the DARPA program because they have already made significant investments in their technologies and have viable plans for achieving fault-tolerant machines with high-qubit numbers in the long term.
DARPA’s long-term funding and resource commitment bring new focus to the three additional technologies of nuclear spin qubits in neutral atoms (Atom Computing), photonic quantum computing (PsiQuantum) and topological quantum (Microsoft). Funding alone can’t overcome the difficult physics and engineering challenges of fault-tolerance, but resource collaboration between the government and private companies could reduce the time needed to develop workable solutions.
While it’s possible that much of the research under this program may not be disclosed, the existence of the program is important to U.S. quantum computing. I anticipate that the program will accelerate the timeline for fault-tolerance, resulting in major progress being achieved in five years instead of the previous prediction of 10.
1. Of the three companies selected by DARPA, Atom Computing is the only one with a working programable quantum prototype. Its first generation machine consists of 100 nuclear spin qubits in an array of optically-trapped neutral atoms. Its second generation machine is being built at its Boulder, Colorado lab. My estimate is that its next machine will have 300-plus qubits of higher fidelity than its first generation machine. Atom has also published a number of research papers geared toward improving its future-generation machines. Scaling potential and coherence is excellent. Considering these factors, I believe Atom Computing has a two- to three-year lead on the other companies going into the five-year US2QC program.
2. PsiQuantum has made amazing progress with fabrication of its chips. That said, I would be more encouraged about the architecture if PsiQuantum had a working prototype. However, PsiQuantum has made it clear that it is not interested in baby steps; it is planning one giant leap to a million qubits. One component still needed to complete its architecture is an ultra-fast optical switch. Because none are available that fit its needs, the last time I talked to PsiQuantum they were building their own switch. Scaling is also a big plus for this architecture. The DARPA program could provide the resources for the giant leap that the company has been working on.
3. Microsoft’s quantum computing research relies on one of the most beautiful quantum theories—but unfortunately, it’s based on theoretical Majorana quasiparticles that no one has ever actually detected. That said, Microsoft researchers believe they have recently detected one of the key signatures of these quasiparticles. If it is possible to create a quantum computer with Majorana quasiparticles, my estimate is that it could take another 15 to 20 years. Collaboration with DARPA might shorten the timeframe by a few years.
4. If all three companies complete DARPA’s five year US2QC program, there will be no losers. Each company will have accelerated its own program and increased the potential and usefulness of its architecture while advancing the state of the art in quantum computing as a whole. Also, considering the funding and the expansive resources being dedicated to the program by DARPA, I believe there is a good chance that at least one of the companies will indeed produce a fault-tolerant quantum computer.