Quantum’s silicon dreams take leap forward

Published on the 29/06/2022 | Written by Heather Wright

Aussie co delivers first integrated circuit at atomic scale…

Australia’s Silicon Quantum Computing has claimed a quantum breakthrough, engineering a quantum processor at atomic scale to simulate the behaviour of a small organic molecule – delivering on a challenge first postulated by theoretical physicist Richard Feynman in 1959.

The development, following 20 years of research, comes two years ahead of schedule and represents a major milestone in the race to build the world’s first quantum computer.

“We know the commercial devices that are within the next five or six years.” 

SQC was formed in 2017 with AU$83 million in seed funding from the Australian federal government, UNSW Sydney, Telstra, Commonwealth Bank and the NSW government, and is headed up by renowned quantum physicist Professor Michelle Simmons.

While classical computers are programmed with bits as data units (zeros and ones), quantum uses qubits, which represent a combination of both zero and one at the same time, based on a principle called superposition.

That gives quantum computers the potential to be exponentially faster than today’s offerings, performing multiple calculations with multiple inputs simultaneously That enables quantum computers to explore a gigantic number of paths simultaneously, delivering multiple results in a tight range to get you closer to the answer far faster than classical computers can.

“Today’s classical computers struggle to simulate even relatively small molecules due to the large number of possible interactions between atoms,” Simmons says. 

“Development of SQC’s atomic-scale circuit technology will allow the company and its customers to construct quantum models for a range of new materials, whether they be pharmaceuticals, materials for batteries, or catalysts.

“It won’t be long before we can start to realise new materials that have never existed before,” she says.

A key issue for quantum is the high susceptibility to errors and the need to reduce the noise in the signals – something SQC believes it has now cracked. 

The SQC chip is able to simulate a polyacetylene molecule, with a chain of 10 quantum dots simulating the precise location of atoms in the polyacetylene chain.

Referencing Feynman’s 1959 seminal lecture, Plenty of Room at the Bottom, SQC notes Feynman said if you want to understand how nature works you have to be able to control matter at the same length scales from which matter is constructed.

“So that’s what we’re doing, we’re literally building it from the bottom up, where we are mimicking the polyacetylene molecule by putting atoms in silicon with the exact distances that represent the single and double carbon-carbon bonds,” Simmons says. 

The breakthrough delivers on Feynman’s challenge, with an integrated circuit using atomic components in silicon. It comes less than a decade after the team declared it had created the world’s first single atom transistor.

SQC says to achieve the first quantum integrated circuit SQC required realisation of three separate technological feats of atomic engineering.

The first was to create such small dots of atoms of uniform size so that their energy levels aligned and electrons could easily pass through them.

The second was the ability to tune the energy levels of each dot individually, but also of all dots collectively, to control the passage of quantum information.

The third was the teams’ ability to control the distances between the dots with sub-nanometre precision so that the dots were close enough but remained independent for the quantum coherent transport of electrons across the chain.

The ARC Centre of Excellence for Quantum Computation and Communication Technology, working with SQC, announced in late 2020 that it had found the ‘sweet spot’ for positioning qubits in silicon to scale up atom-based quantum processors.

SQC’s work has been hailed as a major breakthrough, with Minister for Industry and Science Ed Husic saying it will help industries construct quantum models for a range of new products such as pharmaceuticals, materials for batteries and catalysts. 

Australia has been pushing quantum. There are already more than 17 quantum related companies in the country which have received funding and investment of more than AU$400 million.

The federal government’s $1 billion Critical Technology Fund – part of the boarder National Reconstruction Fund – is designed to help support home-grown innovation and production in areas including quantum and up to $4 million has also been provided for up to 20 PhDs in quantum research to support universities in establishing research and education partnerships. 

“Quantum technology breakthroughs in communications, sensing and computing boost this strategically important sector, which is estimated to deliver $4 billion in economic growth and 16,000 new jobs by 2040,” Husic says.

SQC itself recently kicked off a $130 million funding round. 

It’s also a major technical milestone on the road to achieving SQC’s goal of delivering an error corrected processor. 

For businesses, however, quantum is likely to be a longer term prospect. 

A 2020 McKinsey report noted that most companies won’t reap significant value from quantum computing for a decade or more, though ‘a few’ will see gains ‘in the next five years’. 

Simmons, however, remains bullish about the technology. “We have created a superbly precise manufacturing technology that is opening the door to a whole new world. It is a huge step towards building a commercial quantum computer,” she says.

“It is a hugely exciting result and what is even more exciting for us is having done that, we have seen that classical roadmap and that we know the commercial devices that are within the next five or six years.” 

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