Most quantum computer designs only work at fractions of a degree above absolute zero, an environment that is very expensive to achieve and maintain.
Researchers led by Professor Andrew Dzurak at UNSW Sydney have developed a way of producing 'hot qubits' – quantum devices that operate at 1.5 Kelvin.
"Our new results open a path from experimental devices to affordable quantum computers for real world business and government applications," said Professor Dzurak.
"This [1.5 Kelvin] 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."
In a paper published in the journal Nature, Dzurak's team and collaborators in Canada, Finland and Japan reported a proof-of-concept quantum processor unit cell that operates at this relatively warm temperature.
The unit cell comprises two qubits confined in a pair of quantum dots embedded in silicon. Significantly, a scaled-up version could be manufactured using existing silicon chip foundries.
"Every qubit pair added to the system increases the total heat generated," explains Dzurak, "and added heat leads to errors. That's primarily why current designs need to be kept so close to absolute zero."
The UNSW team's approach is to initialise and 'read' the qubit pairs by using electrons tunnelling between the two quantum dots.
The proof-of-principle experiments were performed by UNSW's Henry Yang, who Dzurak describes as a "brilliant experimentalist".
The warmer – or should that be less cold? – operating temperature also makes it easier to integrate the quantum processor with conventional silicon chips.