Australian researchers confirm the promise of silicon for quantum computing.

Australian researchers confirm the promise of silicon for quantum computing.

Australian researchers have measured the fidelity of two-qubit logic operations in silicon for the first time ever, with highly promising results that will allow a full-scale quantum processor to be scaled.

The research, conducted by the UNSW Engineering team of Professor Andrew Dzurak, has been published in the world-renowned journalNature today. The true accuracy of such a two-qubit gate was unknown until this landmark paper today.

Australian researchers confirm the promise of silicon for quantum computing.

Dzurak's team was the first to construct a quantum logic gate in silicon in 2015, enabling calculations between two qubits of information – and thus clearing up a crucial hurdle to make silicon quantum computers a reality.

Important accuracy for success of quantum computing

In this study, the team applied and conducted Clifford-based fidelity benchmarking-a technique that can assess qubit accuracy across all technology platforms-showing an average fidelity of 98 percent to two-qubit gates.

“Most of important Quantum applications, millions of qubits will be needed, and you're going to have to correct quantum errors, even when they’re small,” Professor Dzurak says.

“The more accurate your qubits, the fewer you need – and therefore, the sooner we can ramp up the engineering and manufacturing to realise a full-scale quantum computer.”

Concrete path to silicon in quantum computing

“If our fidelity value had been too low, it would have meant serious problems for the future of silicon quantum computing. The fact that it is near 99% puts it in the ballpark we need, and there are excellent prospects for further improvement. Our results immediately show, as we predicted, that silicon is a viable platform for full-scale quantum computing,” Professor Dzurak says.

Recently published in Nature Electronics and featured on its cover – where Dr. Yang is the lead author, the same team also recorded the world's most accurate 1-qubit gate in a silicon quantum dot with a remarkable 99.96 percent fidelity.

“Besides the natural advantages of silicon qubits, one key reason we’ve been able to achieve such impressive results is because of the fantastic team we have here at UNSW. My student Wister and Dr Yang are both incredibly talented. They personally conceived the complex protocols required for this benchmarking experiment,” says Professor Dzurak.

UNSW Dean of Engineering, Professor Mark Hoffman, says “Quantum computing is this century’s space race – and Sydney is leading the charge.”

“This milestone is another step towards realising a large-scale quantum computer – and it reinforces the fact that silicon is an extremely attractive approach that we believe will get UNSW there first.”

Professor Dzurak is leading a project with Silicon QuantumComputing, Australia's first quantum computing company, to advance silicon CMOS qubit technology.

“Our latest result brings us closer to commercialising this technology – my group is all about building a quantum chip that can be used for real-world applications,” Professor Dzurak says.

The silicon qubit device used in this study was manufactured entirely at UNSW using a unique silicon-CMOS process line, high-resolution patterning systems, and supporting equipment made available by ANFF-NSW for nanofabrication.

For more information in detail:  Quantum world-first: researchers can now tellhow accurate two-qubit calculations in silicon really are