Startup Quantum Motion joins the silicon spin qubit gang with a proprietary technology that can put thousands of quantum dots on a single silicon chip made in a commercial semiconductor foundry. The move marks a small step along the way to building a full-fledged, fault-tolerant quantum system.
The company, led by academics from UCL and the University of Oxford, claims to have achieved an important milestone in measuring the state of quantum devices on one of its chips, measuring 1,024 quantum dots covering an area of less than 0.1 mm. It states that it has demonstrated the dot.2 It can be measured within 12 minutes.
Quantum Motion said its results were presented at the recent IEEE International Conference on Electronic Circuits and Systems in Glasgow, UK.
The latest chip called Bloomsbury is 3x3mm2 Devices manufactured in a “Tier 1 Foundry” using the same mass production processes used in standard semiconductor manufacturing. Bloomsbury, named after the part of London where the company first set up its factory, contains thousands of quantum dots that can be loaded with individual electrons to act as qubits.
A microscope view of the Bloomsbury chip shows wire bonds to the PCB.
According to Quantum Motion, moving from today’s small quantum processor demonstrations to large-scale quantum computers requires overcoming several challenges. One of these is simply putting together enough qubits, and being able to mass-produce quantum devices using existing chip manufacturing techniques is one answer.
Another, the company says, is a way to address individual qubits in large arrays without requiring a huge number of connections to the quantum device. To achieve this, not only are quantum devices manufactured in the same processes used to manufacture traditional electronics, but the electronic control circuitry is designed to function at the extremely low temperatures required to operate qubits. need to do it.
“By integrating these [quantum dots] On-chip with conventional electronics designed to operate at cryogenic temperatures, thousands of quantum devices could be read from just nine wires in a refrigerator. It removes a huge scaling bottleneck,” said Alberto Gomez Saiz, Quantum Motion Integrated Circuit Lead.
Yonatan Cohen, co-founder and co-CTO of Quantum Machines, agreed that this is another advantage of using silicon to build quantum systems.
“In addition to the fact that we can scale up the number of qubits on a silicon chip, we could also consider integrating some of what we call control electronics, the circuitry that communicates with the qubits. Some of these elements are on the same chip,” Cohen said.
Quantum Machines does not aim to build quantum processors per se, but rather focuses on the hardware and software infrastructure required to run quantum systems.
Cohen said this demonstration by Quantum Motion is an important step on the way to a full-fledged quantum computer.
“I think it’s an important task. As you know, there is a lot of work to be done to get to a full-scale quantum computer. But this is a very important milestone, and there I think it shows that we are heading in the right direction.”
According to Quantum Motion, their chips are made in an unidentified commercial foundry using a 300mm wafer fabrication process used for high-yield, high-volume chip manufacturing. In this regard, the company has followed a similar path to Intel, which earlier this month announced the latest results from its own experiments on manufacturing spin qubit devices using 300mm wafers.
Co-CTO John Morton hailed this as the result of a major interdisciplinary effort by Quantum Motion’s semiconductor engineers and quantum physicists, who said that by mass-producing quantum chips using advanced silicon foundry processes, He said that it shows the possibility of realizing a quantum processor.
But, as Cohen told us, the industry is still a long way from seeing a universal quantum system that can deliver on the promises made for this technology.
“It really depends on what you mean when you say general-purpose or large-scale quantum computer,” he said. “If you want to get to what we call a fault-tolerant, large-scale quantum computer, I think it will take 10 to 15 years, maybe 20 years. For example, the Shor algorithm that breaks RSA codes.”
Before that, Cohen argued that there are heuristic algorithms that could bring significant advantages to quantum computers within the next five to seven years, but we won’t know until they are tested. I likened it to learning. Machine learning was an unproven technology until people built neural networks and found them useful for specific applications.
“So people are building those machines and trying them out to see if these algorithms work,” Cohen said, noting that even if we need a general-purpose quantum computer in the future, we won’t. I added that there is a lot of work that needs to be done. you need to start it today. ®