Scientists design full-scale architecture for quantum computer in silicon

October 30, 2015, University of New South Wales
From left to right Dr Matthew House, Sam Hile (seated), Scientia Professor Sven Rogge and Scientia Professor Michelle Simmons of the ARC Centre of Excellence for Quantum Computation and Communication Technology at UNSW. Credit: Deb Smith, UNSW Australia

Australian scientists have designed a 3D silicon chip architecture based on single atom quantum bits, which is compatible with atomic-scale fabrication techniques - providing a blueprint to build a large-scale quantum computer.

Scientists and engineers from the Australian Research Council Centre of Excellence for Quantum Computation and Communication Technology (CQC2T), headquartered at the University of New South Wales (UNSW), are leading the world in the race to develop a scalable quantum computer in silicon - a material well-understood and favoured by the trillion-dollar computing and microelectronics industry.

Teams led by UNSW researchers have already demonstrated a unique fabrication strategy for realising atomic-scale devices and have developed the world's most efficient in silicon using either the electron or nuclear spins of single phosphorus atoms. Quantum bits - or qubits - are the fundamental data components of quantum computers.

One of the final hurdles to scaling up to an operational quantum computer is the architecture. Here it is necessary to figure out how to precisely control multiple qubits in parallel, across an array of many thousands of qubits, and constantly correct for 'quantum' errors in calculations.

Now, the CQC2T collaboration, involving theoretical and experimental researchers from the University of Melbourne and UNSW, has designed such a device. In a study published today in Science Advances, the CQC2T team describes a new silicon architecture, which uses atomic-scale qubits aligned to control lines - which are essentially very narrow wires - inside a 3D design.

"We have demonstrated we can build devices in silicon at the atomic-scale and have been working towards a full-scale architecture where we can perform error correction protocols - providing a practical system that can be scaled up to larger numbers of qubits," says UNSW Scientia Professor Michelle Simmons, study co-author and Director of the CQC2T.

How to build a quantum computer in silicon

"The great thing about this work, and architecture, is that it gives us an endpoint. We now know exactly what we need to do in the international race to get there."

In the team's conceptual design, they have moved from a one-dimensional array of qubits, positioned along a single line, to a two-dimensional array, positioned on a plane that is far more tolerant to errors. This qubit layer is "sandwiched" in a three-dimensional architecture, between two layers of wires arranged in a grid.

By applying voltages to a sub-set of these wires, multiple qubits can be controlled in parallel, performing a series of operations using far fewer controls. Importantly, with their design, they can perform the 2D surface code error correction protocols in which any computational errors that creep into the calculation can be corrected faster than they occur.

"Our Australian team has developed the world's best qubits in silicon," says University of Melbourne Professor Lloyd Hollenberg, Deputy Director of the CQC2T who led the work with colleague Dr Charles Hill. "However, to scale up to a full operational quantum computer we need more than just many of these qubits - we need to be able to control and arrange them in such a way that we can correct errors quantum mechanically."

"In our work, we've developed a blueprint that is unique to our system of qubits in silicon, for building a full-scale quantum computer."

In their paper, the team proposes a strategy to build the device, which leverages the CQC2T's internationally unique capability of atomic-scale device fabrication. They have also modelled the required voltages applied to the grid wires, needed to address individual qubits, and make the processor work.

"This architecture gives us the dense packing and parallel operation essential for scaling up the size of the quantum processor," says Scientia Professor Sven Rogge, Head of the UNSW School of Physics. "Ultimately, the structure is scalable to millions of , required for a full-scale quantum processor."


In classical computers, data is rendered as binary bits, which are always in one of two states: 0 or 1. However, a qubit can exist in both of these states at once, a condition known as a superposition. A qubit operation exploits this quantum weirdness by allowing many computations to be performed in parallel (a two-qubit system performs the operation on 4 values, a three-qubit system on 8, and so on).

As a result, quantum computers will far exceed today's most powerful super computers, and offer enormous advantages for a range of complex problems, such as rapidly scouring vast databases, modelling financial markets, optimising huge metropolitan transport networks, and modelling complex biological molecules.

Explore further: Crucial hurdle overcome in quantum computing

More information: A surface code quantum computer in silicon, Science Advances, DOI: 10.1126/sciadv.1500707

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1.8 / 5 (5) Oct 30, 2015
What if The Very First Proponent of Quantum Computer had come across this Information? What could have been HIS reaction? I Strongly believe that all Images of EVERYTHING are compiled & recorded as Videos "SOMEWHERE" like on DVD from The Very Beginning itself. May be in tne Sand Grains transferred from one to the other in entanglement. May be in SOMETHING Unthought of! It is just a matter of coming up with the required technology in one fine Century OR Millennium to visualize it all! Of course, then, We would need a Quantum Computer like Brain to Run through the ENTIRE Video and Grasp it All in a Nanosecond OR Planck time, the time light takes to travel one Planck length. theoretically, the smallest time measurement that will ever be possible! The base unit of time in Western world is the second, defined as about 9 thousand million periods of radiation of the caesium atom.
Whydening Gyre
5 / 5 (4) Oct 31, 2015
Wouldn't that be about 9 BILLION...?
3.7 / 5 (3) Oct 31, 2015
This is good new. Next fundamental step is to make this architechture real thing and check if their theory is confirmed by reality.
1 / 5 (4) Nov 01, 2015
viko_mx states
This is good new. Next fundamental step is to make this architechture real thing and check if their theory is confirmed by reality
So when you claim "I know physics very well" and that you claim relativity is a lie & conspiracy and ignore the empirical evidence.

What are we to make of your claims it comes down to a 'creator' ?

I have asked you many times viko_mx to explain just why your 'creator' is such a bad communicator ?

viko_mx please prove your claim you know physics well when you betray the fact you have no understanding of the essential mathematics of Physics: Probability, Statistics, Calculus, Measurement Methods etc.

viko_mx why are you here try to proselytize but claim Eg relativity is false and that the GPS programmers who have to write software to accommodate relativity have faked it ?

viko_mx why are you here at all if not to promote religion ?

Can someone ban viko_mx please, he's shown evidence of anti-science behaviour ?
not rated yet Nov 01, 2015
The thing that most of you "preachers" should begin by conceeding is that, 'We dont know anything...for certain', but we have some damn good approximations. In fact, some of our science is so good, they're considered 'proven' theories of how the world works. The one thing our science cant do, is tell you anything about 'God'. Stop confusing faith with the process of science. For the debunkers, a persons faith is a personal thing, rooted in the junction between their head and their heart. All the science in the world can't prove them wrong. Science and Belief. You can barely compare them in the same sentence.

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