For decades, the pursuit of quantum computing has struggled with the need for extremely low temperatures, just fractions of a degree above absolute zero (0 Kelvin or –273.15°C).
This is because the quantum phenomena that give quantum computers their unique computational capabilities can only be harnessed by isolating them from the warmth of the familiar classical world we inhabit.
A single quantum bit or “qubit,” the equivalent of the binary “zero or one” bit at the heart of classical computing, requires a large cooling apparatus to operate. However, in many areas where we expect quantum computers to generate breakthroughs – such as in the design of new materials or drugs – we will need large numbers of qubits or even entire quantum computers working in parallel.
Quantum computers that can handle errors and self-correct, essential for reliable calculations, are predicted to be gigantic in scale. Companies like Google, IBM and PsiQuantum are preparing for a future with entire warehouses filled with cooling systems and consuming enormous amounts of energy to run a single quantum computer.
But if quantum computers could operate at even slightly higher temperatures, they could be much easier to operate and much more available. In new research published in NatureOur team has shown that a certain type of qubit (single electron spins) can operate at temperatures of around 1 K, much higher than previous examples.
The cold hard facts
Cooling systems become less efficient at lower temperatures. To make matters worse, the systems we use today to control qubits are tangles of intertwined wires reminiscent of ENIAC and other huge computers of the 1940s. These systems increase heating and create physical obstacles for qubits to work together.
The more qubits we try to fit in, the more difficult the problem becomes. At some point, the wiring problem becomes insurmountable.
After that, the control systems must be integrated into the same chips as the qubits. However, these integrated electronics consume even more power (and dissipate more heat) than the big mess of cables.
A warm twist
Our new research may offer a way forward. We have shown that a particular type of qubit (one made from a quantum dot printed with metal electrodes on silicon, using technology very similar to that used in existing microchip production) can operate at temperatures of around 1K.
This is only one degree above absolute zero, so it is still very cold. However, it is much hotter than previously thought possible. This advancement could condense the growing cooling infrastructure into a single, more manageable system. It would drastically reduce operating costs and energy consumption.
The need for such technological advances is not merely academic. The stakes are high in fields like drug design, where quantum computing promises to revolutionize the way we understand and interact with molecular structures.
Research and development expenditures in these industries, running into billions of dollars, underscore the potential cost savings and efficiency gains from more accessible quantum computing technologies.
A slow burn
“Hotter” qubits offer new possibilities, but will also introduce new challenges in error correction and control. Higher temperatures may well mean an increase in the rate of measurement errors, which will create more difficulties in keeping the computer running.
It is still early in the development of quantum computers. Quantum computers may one day be as ubiquitous as today’s silicon chips, but the road to that future will be filled with technical obstacles.
Our recent progress in operating qubits at higher temperatures is a key step in simplifying system requirements.
It offers hope that quantum computing can break free from the confines of specialized laboratories and enter the broader scientific community, industry and commercial data centers.
Andrew Dzurak, Scientia Professor Andrew Dzurak, CEO and Founder of Diraq, UNSW Sydney and Andre Luiz Saraiva De Oliveira, Solid State Physicist, UNSW Sydney
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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