Newly Invented Device Controls Thousands of Qubits

A team of scientists and engineers at the University of Sydney and Microsoft Corporation have teamed up to develop a new device that has big implications for quantum computing. The single chip can operate 40 times colder than deep space, and it is capable of controlling signals for thousands of qubits, which are the fundamental building blocks of quantum computers.

The results were published in Nature Electronics. 

Professor David Reilly is the one responsible for designing the chip. He has a joint position with the University of Sydney and Microsoft.

“To realise the potential of quantum computing, machines will need to operate thousands if not millions of qubits,” said Professor Reilly. 

“The world's biggest quantum computers currently operate with just 50 or so qubits,” he continued. “This small scale is partly because of limits to the physical architecture that control the qubits. Our new chip puts an end to those limits.”

Quantum Systems

One of the main requirements of an efficient quantum system is qubits to operate at temperatures around zero, or -273.15 degrees. The reason for this temperature requirement is so that the qubits do not lose their character of matter or light, which is required by quantum computers to perform specialized applications. 

One of the reasons quantum systems often involve many wires is that they operate based on instructions, which come in the form of electrical signals sent and received.

Professor Reilly is also the Chief Investigator at the ARC Centre for Engineered Quantum Systems (EQUS). 

“Current machines create a beautiful array of wires to control the signals; they look like an inverted gilded birds' nest or chandelier. They're pretty, but fundamentally impractical. It means we can't scale the machines up to perform useful calculations. There is a real input-output bottleneck,” said Professor Reilly.

According to Dr. Kushal Das, Microsoft Senior Hardware Engineer and joint inventor of the device, “Our device does away with all those cables. With just two wires carrying information as input, it can generate control signals for thousands of qubits. This changes everything for quantum computing.”

Microsoft Quantum Laboratories

The new chip was invented at the Microsoft Quantum Laboratories, which is located at the University of Sydney. The partnership brings together the two different worlds to come up with innovative approaches to engineering challenges.

“Building a quantum computer is perhaps the most challenging engineering task of the 21st century. This can't be achieved working with a small team in a university laboratory in a single country but needs the scale afforded by a global tech giant like Microsoft,” Professor Reilly said.

“Through our partnership with Microsoft, we haven't just suggested a theoretical architecture to overcome the input-output bottleneck, we've built it.

“We have demonstrated this by designing a custom silicon chip and coupling it to a quantum system,” he said. “I'm confident to say this is the most advanced integrated circuit ever built to operate at deep cryogenic temperatures.”

The newly developed chip could play a major role in advancing quantum computers, which are one of the most revolutionary technologies within our grasp. Quantum computers are extremely advanced in their abilities to solve problems that classical computers cannot, such as those within the fields of cryptography, medicine, AI, and more.