Researchers in Australia have shown for the first time that a critical technique for creating a quantum computer is no longer impossible.

We’re still some way off before access to quantum computers is as available as laptops are today, but researchers at the University of New South Wales Sydney have helped us take a major leap towards that goal.

Publishing a paper to Nature Nanotechnology, a research team revealed it has built atomic precision qubits in a 3D device, the first time it has ever been achieved. This technique can be extended to multiple layers of a silicon crystal, a critical component of 3D chip architecture.

Within the design, atomic-scale qubits are aligned to very narrow wires known as control lines within a 3D design. While a highly complicated process, the 3D architecture is a significant advancement for atomic qubits in silicon and will be crucial for the computer’s ability to correct errors in quantum calculations.

This ability to control many qubits in parallel is achieved by aligning the different layers of silicon crystal in the 3D device with precision down to just five nanometres. The team demonstrated that they could read out qubit states with one single measurement with high fidelity.

‘In the past, critics would say that that’s not possible’

“This 3D device architecture is a significant advancement for atomic qubits in silicon,” said quantum physicist Prof Michelle Simmons, who was named as Australian of the Year for 2018.

Her colleague and co-author of the study, Dr Joris Keizer, said the fact the team was able to demonstrate how to build a second layer on top of the first layer of qubits was “quite extraordinary”.

Keizer continued: “In the past, critics would say that that’s not possible because the surface of the second layer gets very rough, and you wouldn’t be able to use our precision technique any more; however, in this paper, we have shown that we can do it, contrary to expectations.”

While saying this is a major milestone in the field of quantum computing, Simmons admitted that we are still at least another decade away before we see large-scale quantum computers becoming a reality.