Microsoft, PsiQuantum Designing Quantum Computer Prototypes for DARPA US2QC Program

March 13, 2025

By Woodrow Bellamy III

Microsoft unveiled its Majorana 1 quantum processor, pictured here, in a blog post in February. (Microsoft)

The Defense Advanced Research Projects Agency (DARPA) has selected Microsoft and PsiQuantum to move to the final design stage of its Underexplored Systems for Utility-Scale Quantum Computing (US2QC) program, one of two programs under the agency’s larger Quantum Benchmarking Initiative (QBI). This final stage will see the two companies attempt to build utility scale quantum computer prototypes faster than "conventional predictions," according to DARPA's Feb. 6 announcement .

Both Microsoft and PsiQuantum have unveiled their own respective quantum computing breakthroughs within the last month, each coming several weeks after DARPA's US2QC announcement. While DARPA's specific focus is measuring the companies’ prototypes against performance benchmarks that determine whether any quantum computing approach can achieve utility-scale operation, the separate breakthroughs explain how each company could arrive at these prototypes.

Quantum computing differs from classical computing by using atoms rather than transistors to process calculations. Transistors store bits of information in two states, 0s and 1s, whereas quantum computers use quantum mechanics with qubits, which can be 0s, 1s or any number in between at the same time. This concept gives quantum computers the ability to process combinations of data simultaneously.

According to a definition provided by Intel, the properties of quantum physics like superposition and entanglement provide computation for quantum computers. To achieve utility scale practicality, such as what DARPA is seeking with its US2QC prototypes, "commercial quantum systems need to scale to over a million qubits and overcome daunting challenges like qubit fragility and software programmability." In contrast, most of today's quantum computer prototypes and systems only consist of tens or hundreds of entangled qubits, "limiting them from solving real-world problems," according to Intel.

In a Feb. 19 blog written by their Vice President of Quantum Hardware, Chetan Nayak, Microsoft unveiled Majorana 1, a quantum processing unit powered by a topological core "designed to scale to a million qubits on a single chip.” Microsoft published an image of a prototype QPU with a form factor that is similar to some of the latest system-on-chip designs developed by NVIDIA, AMD and Microchip, among others. Nayak's blog post highlights the use of a new class of materials called a "topoconductor" enabled by the fabrication of "gate-defined devices that combine indium arsenide (a semiconductor) and aluminum (a superconductor)."

"When cooled to near absolute zero and tuned with magnetic fields, these devices form topological superconducting nanowires with Majorana Zero Modes (MZMs) at the wires’ ends," Nayak writes.

Microsoft published an accompanying paper in the journal Nature explaining their device architecture for Majorana 1. The breakthrough announcement has faced criticism from researchers however, as explained in a March 7, 2025 Nature article . In the article, Henry Legg, a theoretical physicist at the University of St Andrew in the UK, questions the lack of an explanation on testing included in Microsoft's announcement.

"Known as the topological gap protocol (TGP), the test is not mentioned in the February Microsoft announcement. But the company has subsequently indicated to Nature’s news team, and in a comment online, that it created the topological qubits using the TGP," Nature writes in the article.

In February, PsiQuantum announced Omega, a quantum photonic chipset purpose-built for utility-scale quantum computing pictured here. (Image: PsiQuantum)

Separately, PsiQuantum announced "Omega," which the company describes as a quantum photonic chipset based on single photons that they're already demonstrating can be manufactured at scale. Their silicon photonic chip is based on new materials including a "superconducting material used for highly efficient single-photon detection, and Barium Titanate (BTO), an advanced material for low-loss, and high speed optical switching which is developed and produced by PsiQuantum."

PsiQuantum also introduced a new cooling solution for quantum computers and claims to have the ability to manufacture and cool quantum chips in high volume at the GlobalFoundries facility in New York.

“Omega moves us beyond a science project,” said Pete Shadbolt, PsiQuantum Chief Scientific Officer. “Before we started PsiQuantum, my cofounders and I were in a university lab playing around with a couple of qubits but we knew then that the platform we were using was sorely deficient – we knew that we needed millions of qubits and we knew that implied getting into a mature fab, integration of unlikely components together into a single platform, and climbing a performance curve that at the time seemed borderline impossible. It has been amazing to see how the team has executed on those plans from a decade ago, and it is tremendously exciting to now have the technology in our hands that we will use to build the first commercially useful systems.”

With their respective breakthroughs announced, both companies will now continue into the final stage of DARPA's US2QC program. Since 2023, as part of the program, a team of 50 DARPA test and evaluation experts have evaluated both companies' components, technical approaches, long-term R&D plans and application utility to determine that each currently has the best chance of building a utility-scale quantum computer.

One of the major goals for the US2QC program is the evaluation of underexplored approaches to quantum computing to see if they’re capable of achieving utility-scale operation faster than “conventional predictions.” DARPA defines a utility scale quantum computer as one “whose computational value exceeds its costs.”

Neither company has committed to any specific timeline for building such a prototype, although Nayak claims it will not take "decades" as many experts have projected.

"Microsoft intends to build a fault-tolerant prototype based on topological qubits in years, not decades — a crucial acceleration step toward utility-scale quantum computing," Nayak writes in the blog post.