Diraq discovery promises quantum processing at 10x higher temperatures

28 Mar 2024

Australian startup’s silicon quantum dots herald more powerful, energy-efficient computers.

Quantum computing, expected by many to revolutionize various industries such as materials science, medicine and pharmaceuticals, banking and finance, has faced formidable obstacles in its development, with heat generated by such computers being a significant hindrance.

Diraq’s recent technological breakthrough, described in Nature, features the capability of spin-based quantum processors to operate at temperatures more than ten times hotter than previously possible whilst maintaining stability and high accuracy. Diraq, founded in 2022 as a spinoff from UNSW Sydney, says its innovation allows its quantum computers to be faster, more cost effective, and more environmentally sustainable.

Semiconductor spins are widely considered to be one of the most scalable technologies for quantum processors, due to their compact size and compatibility with existing silicon chip manufacturing.

‘Enabling a practical quantum computer’

“Compared to millikelvin temperatures, temperatures above 1 K relax the constraints imposed by the tiny cooling power of dilution refrigerators by many orders of magnitude, allowing a practical quantum computer with integrated classical control electronics to be operated in a simple cryo-platform,” said Professor Andrew Dzurak, CEO and Founder of Diraq.

Traditional silicon chips generate heat, a familiar challenge when using electronic devices. Several leading quantum computing modalities in the current landscape require cooling to extremely low temperatures, very close to absolute zero (-273.15 °C). At higher temperatures, the qubits falter, rendering the technology impractical.

The new Diraq research demonstrates high-accuracy spin-based quantum computation at temperatures above 1 K, a temperature compatible with the ability of conventional electronics to operate, meaning it is possible to run complex error correction routines required for fault-tolerant quantum computing.

This sets a path to realistic and useful quantum computers, according to Jonathan Huang, lead author and research associate at Diraq, and Ph.D. student at the University of New South Wales.

“This temperature increase, although difficult to grasp when compared to conventional temperature concepts, is actually groundbreaking in the realm of quantum computing,” said Huang. “Our advanced engineering achievement involved a deep understanding of physics as well as the experimental curiosity to push the boundaries of engineering design.”

Prior to this engineering milestone, the heat generated by controlling qubits presented a fundamental challenge to scaling quantum devices.

“The pioneering work of Huang and colleagues demonstrates a spin qubit platform that can operate at elevated temperatures, making it somewhat immune to the heat from control,” said David Reilly, Professor at the University of Sydney. “These results are also of significant practical importance, providing a means of characterising and screening devices without the need for expensive, complex dilution fridges.”

‘Spins in silicon’

Addressing the scale-up challenge in quantum computing to reach millions of qubits, Diraq’s innovative hardware, which is constructed using a novel technology known as spins in silicon, sets the company apart from more established competitors, according to Professor Andrew Dzurak, CEO and Founder.

“While our quantum processors still require refrigeration, the costs and complexity of the overall system are dramatically reduced at these elevated temperatures,” said Dzurak. “Harnessing the power of hot qubits, these quantum computers will enable calculations far beyond the reach of supercomputers that exist today, enabling faster and more accurate predictions and analysis.”

Dr. Henry Yang, Head of Quantum Control at Diraq, was lead author of the team’s previous paper, published in Nature in 2020 that created awareness of the challenges and opportunities of operating ‘hot qubits.’ Motivated by the challenge to achieve high accuracy qubit control, initialization and readout at elevated temperatures, Diraq undertook a meticulous exploration of physical parameters to reach its goal.

With a strategic vision to be an end-to-end quantum computing provider, Diraq aims to combine the value propositions of today’s chip manufacturers, cloud computing companies, and software algorithm providers to unlock the full potential of quantum computing – an industry projected to generate $450 to $850 billion in value creation by 2040 according to analyst Boston Consulting Group.