Hot qubits made in Sydney break one of the biggest constraints to practical quantum computers


A proof-of-concept published today in Nature promises warmer, cheaper and more robust quantum computing. And it can be manufactured using conventional silicon chip foundries.

Most quantum computers being developed around the world will only work at fractions of a degree above absolute zero. That requires multi-million-dollar refrigeration and as soon as you plug them into conventional electronic circuits they’ll instantly overheat.

But now researchers led by Professor Andrew Dzurak at UNSW Sydney have addressed this problem.

“Our new results open a path from experimental devices to affordable quantum computers for real world business and government applications,” says Professor Dzurak.

The researchers’ proof-of-concept quantum processor unit cell, on a silicon chip, works at 1.5 Kelvin – 15 times warmer than the main competing chip-based technology being developed by Google, IBM, and others, which uses superconducting qubits.

“This is still very cold, but is a temperature that can be achieved using just a few thousand dollars’ worth of refrigeration, rather than the millions of dollars needed to cool chips to 0.1 Kelvin,” explains Dzurak.

“While difficult to appreciate using our everyday concepts of temperature, this increase is extreme in the quantum world.”

Quantum computers are expected to outperform conventional ones for a range of important problems, from precision drug-making to search algorithms. Designing one that can be manufactured and operated in a real-world setting, however, represents a major technical challenge.

The UNSW researchers believe that they have overcome one of the hardest obstacles standing in the way of quantum computers becoming a reality.

In a paper published in the journal Nature today, Dzurak’s team, together with collaborators in Canada, Finland and Japan, report a proof-of-concept quantum processor unit cell that, unlike most designs being explored worldwide, doesn’t need to operate at temperatures below one-tenth of one Kelvin.

Read the full article

University: UNSW Sydney

Authors Centre Participants: Prof. Andrew S. Dzurak, Dr. Henry Yang

Other Source: UNSW newsroom