Scientists at the University of Manchester, in collaboration with the University of Melbourne, have produced an ultra-pure form of silicon that allows the construction of high-performance qubit devices for scalable quantum computers.
High-performance qubit devices are a fundamental part of quantum computing, paving the way for their scale up.
The findings, published in Communications Materials – Nature, could revolutionise the future of quantum computing.
Biggest challenges in developing quantum computers
One of the biggest challenges in the development of quantum computers is that qubits are highly sensitive, requiring a stable environment to maintain the information they hold.
Even temperature fluctuations, which are tiny changes in their environment, can cause computer errors.
Another issue is their scale in physical size and processing power.
Ten qubits have the same power as 1,024 bits in a normal computer and can occupy a much smaller volume.
A fully performing quantum computer needs around one million qubits, providing the capability unfeasible by any classical computer.
Silicon’s role in computing
Silicon is the underpinning material in classical computing due to its semiconductor properties.
The team believes it could be the answer to scalable quantum computers. However, using silicon in quantum computers presents challenges.
Natural silicon is made up of three atoms of different mass – silicon 28, 29 and 30. However, the Si-29, making up around 5% of silicon, triggers a ‘nuclear flip-flopping’ effect, causing the qubit to lose information.
Now, scientists have developed a way to remove silicon 29 and 30 atoms, making it the perfect material to make quantum computers at scale and with high accuracy.
The world’s purest silicon provides a pathway to the creation of one million qubits.
Ravi Acharya, a PhD researcher who performed experimental work in the project, explained: “The great advantage of silicon quantum computing is that the same techniques that are used to manufacture the electronic chips — currently within an everyday computer that consist of billions of transistors — can be used to create qubits for silicon-based quantum devices.
“The ability to create high quality silicon qubits has in part been limited to date by the purity of the silicon starting material used. The breakthrough purity we show here solves this problem.”
A roadmap to scale up quantum devices
The breakthrough offers a roadmap towards scalable quantum computers with unparalleled performance and capabilities.
It holds the promise of transforming technologies in ways hard to imagine.
Project co-supervisor, Professor David Jamieson, from the University of Melbourne, said: “Our technique opens the path to reliable quantum computers that promise step changes across society, including in artificial intelligence, secure data and communications, vaccine and drug design, and energy use, logistics and manufacturing.
“Now that we can produce extremely pure silicon-28, our next step will be to demonstrate that we can sustain quantum coherence for many qubits simultaneously. A reliable quantum computer with just 30 qubits would exceed the power of today’s supercomputers for some applications.”
