Quantum lab aims to build silicon circuits with millions of qubits

Quantum lab aims to build silicon circuits with millions of qubits

Quantum Motion lab Islington.jpg

A company backed by two universities and the security services has opened a lab in London so that potential users can explore quantum computing.

The company, Quantum Motion, plans to use well-tried techniques of silicon-based integrated circuits to make the technology cheaper and more widely available.

“We want to focus on a technology that will scale,” CTO James Morton told Capacity at the company’s headquarters. “We’re harnessing the millions of dollars that have gone in silicon fabrication. We want to use that for a silicon-based quantum computer.”

Quantum Motion has built a team – based in Islington, one stop on the Underground from King’s Cross and St Pancras stations – that includes integrated circuit (IC) engineers and software engineers as well as quantum physicists and quantum computing architects.

The company is a spin-off from Oxford University and University College London (UCL), but it also has investment from the little-known National Security Strategic Investment Fund, a UK government venture capital arm with heavy involvement from the spy agencies, including MI6 – the Secret Intelligence Service – and GCHQ, the UK equivalent of the US National Security Agency.

Quantum computing is likely to have two significant impacts in the intelligence world. First, it will make it possible to encrypt data to a higher, more secure, level than ever before. Second, data that has been encrypted to current standards will become readable. There is a widespread suspicion that governments and other organisations are storing today’s unreadable data for the day when it will be possible to read it.

Quantum Motion says its decision to use silicon transistors is key to its different approach. The world has a significant number of silicon foundries that build the ICs in computers, data centres, phones and virtually every electronic device.

James Palles-Dimmock, the company’s chief operating officer, told Capacity: “Around US$500 billion has been ploughed into the silicon industry.”

Morton said: “Our focus is to develop a scalable unit which can be a key proof you can build a quantum processor with silicon. If you can, why would you want to do it any other way?”

The company plans to outsource fabrication of its quantum devices to silicon foundries. There are no longer any significant installations in the UK, the industry having consolidated to Asia and the US.

The US-based Nasdaq exchange lists the top five as Taiwan Semiconductor Manufacturing (TSM), Samsung of South Korea, Taiwan’s United Microelectronics Corporation (UMC), US-based GlobalFoundries and China’s Semiconductor Manufacturing International Corporation (SMIC).

“We have already got many chips back from different foundries,” said Palles-Dimmock. Morton noted: “Silicon foundries are tens of billion-dollar facilities supporting the entire industry.”

Quantum Motion’s aim is to build its devices into equipment that will be housed in standard 19-inch racks as seen in every telecoms operator, data centre and IT department in the world. (AT&T set the 19-inch standard for equipment racks in 1922, a century ago, and wrote about it in the Bell System Technical Journal in July 1923.)

Current technology limits quantum computers to around 50 to 100 qubits, or quantum bits, but “we’re going to need millions of qubits” for serious applications, said Morton. He thinks that is feasible with Quantum Motion’s silicon-based approach.

The company’s lab is just a few metres from its front door, just off the Caledonian Road in Islington. In there, Morton and his colleagues showed Capacity a Doctor Who’s Tardis-like cylindrical construction of bright, ultra-pure copper in which the company is developing the technology.

In use, the assembly is held in a giant stainless-steel vacuum flask, made by Bluefors of Finland, and held at very low temperatures. “Up here,” said Morton, pointing to the top of the unit, “it is about the temperature of Neptune. There, in the middle, is the temperature of outer space.”

The temperature of Neptune is around −223°C, he explained, or 50 kelvin (50K) in scientific terms. The kelvin scale starts at absolute zero, −273.15°C, known as 0K.

Morton pointed to a number of copper-coloured cylinders, called pucks, attached to the bottom of the unit: “Down here the temperature is 10 millikelvin.” That is the temperature at which the quantum effects will operate, keeping single electrons in one of two quantum states – spin up and spin down – for nine seconds.

“Qubits are [determined by] the spin of the electron,” Morton told Capacity. “That nine seconds indicates the device is very stable. It is much longer in silicon than in other materials.”

The goal of Quantum Motion is “to put hundreds of millions of qubits into a puck”, he added. “We’re developing a fault-tolerant universal quantum computer.”

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