Aussie scientists solve 60-year quantum computing challenge

Researchers from the University of New South Wales (UNSW) and Australian start-up Silicon Quantum Computing (SQC) have engineered a quantum processor at the atomic scale, marking a major milestone in the world of quantum computing.

The breakthrough, published in the journal Nature, would allow the simulation of the behavior of small organic molecules, putting to rest a challenge first set out some 60 years ago by theoretical physicist Richard Feynman.

“If you go back to the 1950s, Richard Feynman said you can’t understand how nature works unless you can build matter at the same length scale,” said lead researcher and UNSW Scientia Professor Michelle Simmons.

The researchers were able to mimic the structure and energy states of the organic compound polyacetylene — a repeating chain of carbon and hydrogen atoms distinguished by alternating single and double bonds of carbon.

The team built a quantum circuit with 10 “dots” that “matched perfectly” with an organic polyacetylene chain.

Simmons said the finding was ground-breaking as it would allow them to mimic and thus simulate a variety of molecules.

“And so that means that now we can start to understand more and more complicated molecules based on putting the atoms in place as if they’re mimicking the real physical system … there’re huge implications for fundamentally understanding how nature works,” said Simmons.

The carbon chain of 10 atoms created would have the capacity equivalent to that of a classical computer. However, as they increase the length of the chain the computing power would in turn increase exponentially.

“We’re near the limit of what classical computers can do, so it’s like stepping off the edge into the unknown.”

Quantum computers, unlike classical computers that operate on binary of 1 or 0, take advantage of the variety of states meaning they are able to run thousands and possibly millions of calculations simultaneously.

The team believes that the discovery represents a fundamental step in the roadmap towards making quantum computing a reality.

“If we map it to the evolution of classical computing, we’re predicting we should have some kind of commercial outcome from our technology five years from now,” said Simmons. ■