Mr. Eugene Profis reports

QUANTUMCORE BEGINS DEVELOPMENT OF THIRD CRITICAL TECHNOLOGY FOR SCALABLE QUANTUM COMPUTING

Quantumcore Ltd. has begun development of a third critical technology for its quantum computing infrastructure platform: multiplexing microchips, designed to significantly reduce the number of physical interconnects required between room-temperature control electronics and quantum processing units (QPUs).

The development program expands Quantumcore's strategy of building critical hardware within the infrastructure layer between the quantum controller and the QPU. Alongside the company's superconducting quantum amplifier technology and single-photon detector platform, Quantumcore believes cryogenic multiplexing represents another potentially essential enabling technology as quantum computers scale from hundreds and thousands of physical qubits toward systems containing hundreds of thousands and, ultimately, one million physical qubits.

Quantumcore recently entered into a sponsored research agreement with the University of Waterloo covering cryogenic multiplexing for quantum computer applications. The program is led by Prof. Raafat Mansour of Waterloo's department of electrical and computer engineering.

Addressing the million-qubit wiring problem

Today, superconducting quantum computers generally require microwave, DC (direct-current) control and readout connections extending from room-temperature electronics through multiple temperature stages of a dilution refrigerator to the millikelvin environment surrounding the QPU.

As processors become larger, this architecture creates an increasingly difficult physical and thermal bottleneck. Dense wiring consumes valuable space, adds heat to the extremely limited cooling capacity of the mixing chamber, and can introduce signal latency, attenuation and crosstalk. The research program identifies the cryogenic wiring interconnect bottleneck as one of the primary obstacles to scaling quantum hardware and notes that conventional one-wire-per-qubit approaches are expected to become impractical for million-qubit systems because of thermal, physical and bandwidth constraints.

Quantumcore believes cryogenic multiplexing could fundamentally change this architecture.

Instead of maintaining a dedicated physical signal path for every individual qubit, multiplexing switch matrices could allow control and readout infrastructure to be shared and intelligently routed among multiple qubits. The objective is to dramatically reduce the number of cables, connectors and feedthroughs that would otherwise be required as superconducting quantum processors scale.

"The industry is working diligently toward quantum computers containing hundreds of thousands and eventually one million qubits, but you cannot simply scale today's wiring architecture one million times," said Eugene Profis, chief executive officer of Quantumcore. "The interconnect problem becomes a fundamental engineering constraint. We believe cryogenic multiplexing can become an important part of the solution by allowing signals to be routed at cryogenic temperatures and potentially significantly reducing the number of physical connections that have to travel through the refrigerator."

Why phase-change material/superconducting switches

Quantumcore's development program will focus on phase-change material (PCM) switches and superconducting switch matrices for next-generation cryogenic control and readout architectures.

PCM technology is particularly attractive for quantum computing because the switches can provide non-volatile, latching operation. Power is required principally when changing the state of the switch, with virtually no static power required to maintain that state, an important characteristic in a cryogenic environment where every additional source of heat can affect system performance.

The research plan states that PCM switches offer a figure of merit that significantly surpasses state-of-the-art RF CMOS and RF MEMS technologies, making them an outstanding candidate for large-scale cryogenic switch matrices in future quantum computing platforms.

Quantumcore ultimately intends to develop the technology alongside large interconnect, connector and cabling companies as the quantum computing industry works to develop scalable approaches to reducing the number and complexity of physical connections entering dilution refrigerators.

The company believes this creates an opportunity to bridge two critical parts of the emerging quantum hardware ecosystem: advanced cryogenic switching technology and the physical interconnect infrastructure required to connect increasingly large quantum processors.

World-class RF (radio-frequency) and cryogenic engineering expertise

Prof. Mansour is one of Canada's leading experts in microwave engineering and RF integrated circuits, with significant previous work focused on advanced switching technologies and the development of superconducting and cryogenic RF devices. He is a professor in the department of electrical and computer engineering at the University of Waterloo and a former Tier 1 Canada research chair in micronano integrated RF systems and has served two consecutive terms as the NSERC industrial research chair in RF technologies.

Prof. Mansour has an exceptional record of translating university research into commercial technologies. Technologies developed in his research laboratory have contributed to the co-founding of successful Canadian technology companies, including AdHawk Microsystems and Integrated Circuit Scanning Probe Instruments (ICSPI Corp.). Throughout his distinguished career, Prof. Mansour has been awarded 41 Canadian and U.S. patents and has written more than 475 peer-reviewed technical publications. His extensive expertise in advanced RF systems, integrated circuit design, cryogenic superconducting technologies and technology commercialization is expected to support Quantumcore's development of scalable cryogenic multiplexing technologies for future quantum computing platforms.

The cryogenic multiplexing development program builds on prior work conducted in Prof. Mansour's laboratory, which has developed other types of advanced PCM switches and a wide range of RF superconducting circuits, providing an established technology and engineering foundation for the new cryogenic program. Prof. Mansour is also already working on a multiplexing device, which Quantumcore intends to advance and optimize for scalable quantum computing applications. Building on this existing work, the company expects to develop commercial prototypes of its cryogenic multiplexing technology within the next 12 months.

The collaboration will combine Prof. Mansour's technical expertise with Quantumcore's commercialization strategy focused on supplying critical infrastructure technologies to the global quantum computing industry. Prof. Mansour is the principal investigator responsible for the technical content of the research program.

Building the superconducting infrastructure stack

Quantumcore's strategy is to develop a portfolio of technologies addressing critical bottlenecks surrounding the QPU rather than attempting to build the quantum computer itself.

PCM multiplexing would occupy an important position within that superconducting infrastructure stack. Signals originating in room-temperature control systems must be transported, routed, conditioned, amplified and isolated before and after interacting with the QPU. As qubit counts increase, Quantumcore believes greater functionality will need to migrate deeper into the cryogenic environment.

About Quantumcore Ltd.

Quantumcore is a quantum technology company focused on building hardware infrastructure intended to support the scaling of next-generation quantum computing systems. The company's strategy is centred on developing, acquiring and commercializing technologies that operate between classical quantum controllers and quantum processing units.

Quantumcore's portfolio includes superconducting cryogenic signal amplification and advanced photon detection technologies, with the objective of becoming a leading independent supplier of enabling infrastructure to the global quantum computing industry.

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