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

Australian Researchers Unveil First Complete Silicon Quantum ComputerProcessor

Australian Researchers Unveil First Complete Silicon Quantum Computer Processor

UNSW
16 DEC 2017

A reimagining of today’s computer chips by UNSW engineers shows how a quantum computer can be manufactured – using mostly standard silicon technology.

A reimagining of today’s computer chips by Australian and Dutch engineers shows how a quantum computer can be manufactured – using mostly standard silicon technology.

Australian Researchers Unveil First Complete Silicon Quantum Computer Processor

Research teams all over the world are exploring different ways to design a working computing chip that can integrate quantum interactions. Now, UNSW engineers believe they have cracked the problem, reimagining the silicon microprocessors we know to create a complete design for a quantum computer chip that can be manufactured using mostly standard industry processes and components.

The new chip design, published in the journal Nature Communications, details a novel architecture that allows quantum calculations to be performed using existing semiconductor components, known as CMOS (complementary metal-oxide-semiconductor) – the basis for all modern chips.

It was devised by Andrew Dzurak, director of the Australian National Fabrication Facility at the University of New South Wales (UNSW), and Menno Veldhorst, lead author of the paper who was a research fellow at UNSW when the conceptual work was done.

“We often think of landing on the Moon as humanity’s greatest technological marvel,” said Dzurak, who is also a Program Leader at Australia’s famed Centre of Excellence for Quantum Computation and Communication Technology (CQC2T). “But creating a microprocessor chip with a billion operating devices integrated together to work like a symphony – that you can carry in your pocket! – is an astounding technical achievement, and one that’s revolutionised modern life.

“With quantum computing, we are on the verge of another technological leap that could be as deep and transformative. But a complete engineering design to realise this on a single chip has been elusive. I think what we have developed at UNSW now makes that possible. And most importantly, it can be made in a modern semiconductor manufacturing plant,” he added.

Veldhorst, now a team leader in quantum technology at QuTech – a collaboration between Delft University of Technology and TNO, the Netherlands Organisation for Applied Scientific Research – said the power of the new design is that, for the first time, it charts a conceivable engineering pathway toward creating millions of quantum bits, or qubits.

“Remarkable as they are, today’s computer chips cannot harness the quantum effects needed to solve the really important problems that quantum computers will. To solve problems that address major global challenges – like climate change or complex diseases like cancer – it’s generally accepted we will need millions of qubits working in tandem. To do that, we will need to pack qubits together and integrate them, like we do with modern microprocessor chips. That’s what this new design aims to achieve.

“Our design incorporates conventional silicon transistor switches to ‘turn on’ operations between qubits in a vast two-dimensional array, using a grid-based ‘word’ and ‘bit’ select protocol similar to that used to select bits in a conventional computer memory chip,” he added. “By selecting electrodes above a qubit, we can control a qubit’s spin, which stores the quantum binary code of a 0 or 1. And by selecting electrodes between the qubits, two-qubit logic interactions, or calculations, can be performed between qubits.”

A quantum computer exponentially expands the vocabulary of binary code used in modern computers by using two spooky principles of quantum physics – namely, ‘entanglement’ and ‘superposition’. Qubits can store a 0, a 1, or an arbitrary combination of 0 and 1 at the same time. And just as a quantum computer can store multiple values at once, so it can process them simultaneously, doing multiple operations at once.

This would allow a universal quantum computer to be millions of times faster than any conventional computer when solving a range of important problems.

There are at least five major quantum computing approaches being explored worldwide: silicon spin qubits, ion traps, superconducting loops, diamond vacancies and topological qubits; UNSW’s design is based on silicon spin qubits. The main problem with all of these approaches is that there is no clear pathway to scaling the number of quantum bits up to the millions needed without the computer becoming huge a system requiring bulky supporting equipment and costly infrastructure.

That’s why UNSW’s new design is so exciting: relying on its silicon spin qubit approach – which already mimics much of the solid-state devices in silicon that are the heart of the US$380 billion global semiconductor industry – it shows how to dovetail spin qubit error correcting code into existing chip designs, enabling true universal quantum computation.

Unlike almost every other major group elsewhere, CQC2T’s quantum computing effort is obsessively focused on creating solid-state devices in silicon, from which all of the world’s computer chips are made. And they’re not just creating ornate designs to show off how many qubits can be packed together, but aiming to build qubits that could one day be easily fabricated – and scaled up.

“It’s kind of swept under the carpet a bit, but for large-scale quantum computing, we are going to need millions of qubits,” said Dzurak. “Here, we show a way that spin qubits can be scaled up massively. And that’s the key.”

The design is a leap forward in silicon spin qubits; it was only two years ago, in a paper in Nature, that Dzurak and Veldhorst showed, for the first time, how quantum logic calculations could be done in a real silicon device, with the creation of a two-qubit logic gate – the central building block of a quantum computer.

“Those were the first baby steps, the first demonstrations of how to turn this radical quantum computing concept into a practical device using components that underpin all modern computing,” said Mark Hoffman, UNSW’s Dean of Engineering. “Our team now has a blueprint for scaling that up dramatically.

“We’ve been testing elements of this design in the lab, with very positive results. We just need to keep building on that – which is still a hell of a challenge, but the groundwork is there, and it’s very encouraging. It will still take great engineering to bring quantum computing to commercial reality, but clearly the work we see from this extraordinary team at CQC2T puts Australia in the driver’s seat,” he added.

Other CQC2T researchers involved in the design published in the Nature Communications paper were Henry Yang and Gertjan Eenink, the latter of whom has since joined Veldhorst at QuTech.

The UNSW team has struck a A$83 million deal between UNSW, Telstra, Commonwealth Bank and the Australian and New South Wales governments to develop, by 2022, a 10-qubit prototype silicon quantum integrated circuit – the first step in building the world’s first quantum computer in silicon.

In August, the partners launched Silicon Quantum Computing Pty Ltd, Australia’s first quantum computing company, to advance the development and commercialisation of the team’s unique technologies. The NSW Government pledged A$8.7 million, UNSW A$25 million, the Commonwealth Bank A$14 million, Telstra A$10 million and the Australian Government A$25 million.

Source : Complete Design of a Silicon Quantum Qomputer Chip Unveiled

VIDEO, STILLS AND BACKGROUND AVAILABLE

• STILLS: Pictures of Dzurak and Veldhorst, plus illustrations of the complete quantum computer chip. (Photos: Grant Turner/UNSW, Illustrations: Tony Melov/UNSW)


• BACKGROUNDERS: How UNSW’s ‘silicon spin qubit’ design compares with other approaches; plus a free 3,000-word feature article on the UNSW effort (Creative Commons).


• SCIENTIFIC PAPER: Original paper in Nature Communications, “Silicon CMOS architecture for a spin-based quantum computer”.

Australian Quantum Computing Scientist Got Top International Award

Top international award for quantum computing chief

For her world-leading research in the fabrication of atomic-scale devices for quantum computing, Scientia Professor Michelle Simmons has been awarded a prestigious Foresight Institute Feynman Prize in Nanotechnology.

[caption id="attachment_821" align="aligncenter" width="563"] Australian Quantum Computing Scientist Got Top International Award[/caption]

Two international Feynman prizes, named in honour of the late Nobel Prize-winning American physicist Richard Feynman, are awarded each year in the categories of theory and experiment to researchers whose work has most advanced Feynman’s nanotechnology goal of molecular manufacturing.

Professor Simmons, director of the UNSW-based Australian Research Council Centre of Excellence for Quantum Computation and Communication Technology (CQC2T), won the experimental prize from the Foresight Institute for her work in “the new field of atomic-electronics, which she created”.

By creating electronic devices atom by atom, we are gaining a very fundamental understanding of how the world behaves at the atomic scale, and it’s phenomenally exciting.

Her group is the only one in the world that can make atomically precise devices in silicon. They have produced the world’s first single-atom transistor as well as the narrowest conducting wires ever made in silicon, just four atoms of phosphorus wide and one atom high.

President of the Foresight Institute Julia Bossmann said the US $5000 prizes reward visionary research. “Our laureates realise that big innovation is possible on the nanoscale. The prizes acknowledge these pioneering scientists and inspire others to follow their lead.”

Professor Simmons said: “I am delighted to win this award. Feynman once said: ‘What I cannot create, I do not understand’.

“By creating electronic devices atom by atom, we are gaining a very fundamental understanding of how the world behaves at the atomic scale, and it’s phenomenally exciting,” she said.

As director of CQC2T, Professor Simmons heads a team of more than 180 researchers across six Australian universities, including UNSW. She has previously been awarded two Australian Research Council Federation Fellowships and currently holds a Laureate Fellowship.

She has won both the Australian Academy of Science’s Pawsey Medal (2005) and Thomas Ranken Lyle Medal (2015) for outstanding research in physics. She was named NSW Scientist of the Year in 2012, and in 2015 she was awarded the Eureka Prize for Leadership in Science.

In 2014, she had the rare distinction for an Australian researcher of becoming an elected member of the American Academy of Arts and Sciences. She is also editor-in-chief of the first Nature Partner Journal based in Australia, npj Quantum Information.

In April, Prime Minister Malcolm Turnbull opened new quantum computing laboratories at UNSW and praised Professor Simmons’ contribution to the nation as both a scientist and director of the CQC2T team.

“You’re not just doing great work, Michelle. You’re doing the best work in the world,” Mr Turnbull said. “It is a tribute to your leadership, your talent … that you’ve attracted so many outstanding scientists and engineers from around the world. This is a very global team and it’s right here at the University of New South Wales.”

The Forsight Institute is a leading think tank and public interest organisation focused on transformative future technologies. Founded in 1986, its mission is to discover and promote the upsides, and help avoid the drawbacks, of nanotechnology, artificial intelligence, biotechnology and similar life-changing developments.

In 1959, Richard Feynman gave a visionary talk at the California Institute of Technology in which he said: “The problems of chemistry and biology can be greatly helped if our ability to see what we are doing, and to do things on an atomic level, is ultimately developed – a development which I think cannot be avoided.”

Both Feynman Prizes, which were announced overnight in the US, are for 2015. The theory prize was awarded to Professor Marcus Buehler of the Massachusetts Institute of Technology for developing new modelling, design and manufacturing approaches for advance materials with a wide range of controllable properties from the nanoscale to the macroscale.

News Release Source : Top international award for quantum computing chief

Image Credit : UNSW

Australian Prime Minister Hails UNSW's Quantum Computing Research as the World's Best

Opening: Prime Minister hails UNSW's quantum computing research as the world's best

UNSW
Friday, 22 April, 2016

Prime Minister Malcolm Turnbull, accompanied by the Minister for Industry, Innovation and Science, Christopher Pyne, today opened a new quantum computing laboratory complex at UNSW

[caption id="attachment_802" align="aligncenter" width="5760"] Australian Prime Minister Hails UNSW's Quantum Computing Research as the World's Best[/caption]

"There is no bolder idea than quantum computing," said Prime Minister Turnbull, hailing UNSW's research in the transformative technology as the “best work in the world".

He praised the leadership of Scientia Professor Michelle Simmons, director of the Australian Research Council Centre of Excellence for Quantum Computation and Communication Technology (CQC2T) and congratulated the centre's team on their research breakthroughs.

"You're not just doing great work, Michelle, you're doing the best work in the world.

"You're not just solving the computing challenges and determining the direction of computing for Australia, you are leading the world and it is a tribute to your leadership, your talent ... that you've attracted so many outstanding scientists and engineers from around the world,” Mr Turnbull said.

"This is a very global team and it's right here at the University of New South Wales.”

The laboratories will double the productive capacity of the UNSW headquarters of the CQC2T.

They will also be used to advance development work to commercialise UNSW’s ground-breaking quantum computing research and establish Australia as an international leader in the industries of the future. The work has attracted major investment from the Australian Government, the Commonwealth Bank of Australia and Telstra.

CQC2T is leading the international race to build the world’s first quantum computer in silicon.

The new laboratories, which have been funded by UNSW, will house six new scanning tunnelling microscopes, which can be used to manipulate individual atoms, as well as six cryogenic dilution refrigerators that can reach ultra-low temperatures close to absolute zero.

“The international race to build a super-powerful quantum computer has been described as the space race of the computing era,” said Professor Michelle Simmons.

“Our Australian centre’s unique approach using silicon has given us a two to three-year lead over the rest of the world. These facilities will enable us to stay ahead of the competition.”

The new labs will also be essential for UNSW researchers to capitalise on the commercial implications of their work.

In December 2015, as part of its National Innovation and Science Agenda, the Australian Government committed $26 million towards a projected $100 million investment to support the commercial development of UNSW’s research to develop a quantum computer in silicon.

Following the Australian Government’s announcement of support, the Commonwealth Bank of Australia and Telstra each pledged $10 million for the development of a ten-qubit prototype. This prototype will be partly designed and built in the new facility.

“In addition to our fundamental research agenda, we now have an ambitious and targeted program to build a ten-qubit prototype quantum integrated circuit within five years,” said Professor Simmons. “By mapping the evolution of classical computing devices over the last century we would expect commercial quantum computing devices to appear within 5-10 years of that milestone.”

It is a prospect strongly endorsed by UNSW President and Vice-Chancellor Professor Ian Jacobs.

“UNSW is committed to supporting world-leading research, and quantum computing is a key part of our future strategy. We are excited by the opportunities these new laboratories provide us to work jointly with industry and government.

“Our hope, long term, is that this will one day establish Australia as an international leader in one of the key industries of the future,” Professor Jacobs said.

Commonwealth Bank Chief Information Officer David Whiteing said: “Commonwealth Bank is proud to support the University of New South Wales' world-leading quantum computing research team and join the Australian Government in providing tangible support for their National Innovation and Science Agenda.

“In today’s world everyone relies increasingly on computers from those in the palm of our hand to the computers on our desk. Quantum computing is set to increase the speed and power of computing beyond what we can currently imagine. This is still some time in the future, but the time for investment is now. This type of long-term investment is a great example of how collaboration between universities, governments and industry will benefit the nation and our economy, now and into the future.”

Kate McKenzie, Telstra Chief Operations Officer, said that the opening of the new CQC2T laboratories was a significant milestone for science and innovation in Australia.

“In December 2015 we announced our proposed $10 million investment to help with development of silicon quantum computing technology in Australia with CQC2T. It’s an important part of Telstra’s commitment to help build a world class technology nation,” Ms McKenzie said.

“Quantum computing has huge potential globally, so I’m delighted to be here today to see this dynamic, world-leading program.”

Researchers at CQC2T lead the world in the engineering and control of individual atoms in silicon chips

The UNSW-based ARC Centre of Excellence for Quantum Computation and Communication Technology is leading the global race to build the world’s first quantum computer in silicon.

In 2012, a team led by Professor Simmons, of the Faculty of Science, created the world’s first single‑atom transistor by placing a single phosphorus atom into a silicon crystal with atomic precision, achieving a technological milestone ten years ahead of industry predictions. Her team also produced the narrowest conducting wires ever made in silicon, just four atoms of phosphorus wide and one atom high.

In 2012, researchers led by Professor Andrea Morello, of the Faculty of Engineering, created the world’s first qubit based on the spin of a single electron on a single phosphorus atom embedded in silicon.

In 2014, his group then went on demonstrate that these qubits could be engineered to have the longest coherence times (greater than 30 seconds) and highest fidelities (>99.99%) in the solid state.

In 2013, Scientia Professor Sven Rogge, of the Faculty of Science, demonstrated the ability to optically address a single atom, a method that could allow the long-distance coupling of qubits.

And in 2015, researchers led by Scientia Professor Andrew Dzurak, of the Faculty of Engineering, built the first quantum logic gate in silicon – a device that makes calculations between two qubits of information possible. This clears one of the critical hurdles to making silicon-based quantum computers a reality.

More Information Links:

Backgrounder: Quantum computing at UNSW and timeline of major scientific and engineering advances

Backgrounder: New quantum computing laboratories at UNSW

News Release Source : Opening: Prime Minister hails UNSW's quantum computing research as the world's best

Image Credit : UNSW

Australian Researchers Advance Towards Silicon Based Quantum Computer

Atoms placed precisely in silicon can act as quantum simulator

UNSW
22 APR 2016

Coinciding with the opening of a new quantum computing laboratory at UNSW by Prime Minister Malcolm Turnbull, UNSW researchers have made another advance towards the development of a silicon-based quantum computer.

[caption id="attachment_792" align="aligncenter" width="562"]                                       Australian Researchers Advance Towards                          Silicon Based Quantum Computer[/caption]

Coinciding with the opening of a new quantum computing laboratory at UNSW by Prime Minister Malcolm Turnbull, UNSW researchers have made another advance towards the development of a silicon-based quantum computer.

In a proof-of-principle experiment, they have demonstrated that a small group of individual atoms placed very precisely in silicon can act as a quantum simulator, mimicking nature – in this case, the weird quantum interactions of electrons in materials.


“Previously this kind of exact quantum simulation could not be performed without interference from the environment, which typically destroys the quantum state,” says senior author Professor Sven Rogge, Head of the UNSW School of Physics and program manager with the ARC Centre of Excellence for Quantum Computation and Communication Technology (CQC2T).

“Our success provides a route to developing new ways to test fundamental aspects of quantum physics and to design new, exotic materials – problems that would be impossible to solve even using today’s fastest supercomputers.”

The study is published in the journal Nature Communications. The lead author was UNSW’s Dr Joe Salfi and the team included CQC2T director Professor Michelle Simmons, other CQC2T researchers from UNSW and the University of Melbourne, as well as researchers from Purdue University in the US.


Two dopant atoms of boron only a few nanometres from each other in a silicon crystal were studied. They behaved like valence bonds, the “glue” that holds matter together when atoms with unpaired electrons in their outer orbitals overlap and bond.

The team’s major advance was in being able to directly measure the electron “clouds” around the atoms and the energy of the interactions of the spin, or tiny magnetic orientation, of these electrons.

They were also able to correlate the interference patterns from the electrons, due to their wave-like nature, with their entanglement, or mutual dependence on each other for their properties.

“The behaviour of the electrons in the silicon chip matched the behaviour of electrons described in one of the most important theoretical models of materials that scientists rely on, called the Hubbard model,” says Dr Salfi.

“This model describes the unusual interactions of electrons due to their wave-like properties and spins. And one of its main applications is to understand how electrons in a grid flow without resistance, even though they repel each other,” he says.

The team also made a counterintuitive find – that the entanglement of the electrons in the silicon chip increased the further they were apart.

“This demonstrates a weird behaviour that is typical of quantum systems,” says Professor Rogge.

“Our normal expectation is that increasing the distance between two objects will make them less, not more, dependent on each other.

“By making a larger set of dopant atoms in a grid in a silicon chip we could realise a vision first proposed in the 1980s by the physicist Richard Feynman of a quantum system that can simulate nature and help us understand it better,” he says.

Australian Engineers Make Another Quantum Computing Breakthrough

Quantum computer coding in silicon now possible

Strongest possible proof obtained that using entanglement to write executable software code for quantum computers is indeed possible

UNIVERSITY OF NEW SOUTH WALES

17-NOV-2015

A team of Australian engineers has proven -- with the highest score ever obtained -- that a quantum version of computer code can be written, and manipulated, using two quantum bits in a silicon microchip. The advance removes lingering doubts that such operations can be made reliably enough to allow powerful quantum computers to become a reality.



[caption id="attachment_695" align="alignnone" width="650"] Project leader Andrea Morello (left) with lead authors Stephanie Simmons (middle) and                             Juan Pablo Dehollain (right) in the UNSW laboratory where the experiments were performed.[/caption]

The result, obtained by a team at UNSW, appears today in the international journal, Nature Nanotechnology.

The quantum code written at UNSW is built upon a class of phenomena called quantum entanglement, which allows for seemingly counterintuitive phenomena such as the measurement of one particle instantly affecting another – even if they are at opposite ends of the universe.

“This effect is famous for puzzling some of the deepest thinkers in the field, including Albert Einstein, who called it ‘spooky action at a distance’,” said Professor Andrea Morello, of the School of Electrical Engineering & Telecommunications at UNSW and Program Manager in the Centre for Quantum Computation & Communication Technology, who led the research. “Einstein was sceptical about entanglement, because it appears to contradict the principles of ‘locality’, which means that objects cannot be instantly influenced from a distance.”

Physicists have since struggled to establish a clear boundary between our everyday world -- which is governed by classical physics -- and this strangeness of the quantum world. For the past 50 years, the best guide to that boundary has been a theorem called Bell's Inequality, which states that no local description of the world can reproduce all of the predictions of quantum mechanics.

Bell's Inequality demands a very stringent test to verify if two particles are actually entangled, known as the 'Bell test', named for the British physicist who devised the theorem in 1964.

"The key aspect of the Bell test is that it is extremely unforgiving: any imperfection in the preparation, manipulation and read-out protocol will cause the particles to fail the test," said Dr Juan Pablo Dehollain, a UNSW Research Associate who with Dr Stephanie Simmons was a lead author of the Nature Nanotechnology paper.

"Nevertheless, we have succeeded in passing the test, and we have done so with the highest 'score' ever recorded in an experiment," he added.

In the UNSW experiment, the two quantum particles involved are an electron and the nucleus of a single phosphorus atom, placed inside a silicon microchip. These particles are, literally, on top of each other -- the electron orbits around the nucleus. Therefore, there is no complication arising from the spookiness of action at a distance.

However, the significance of the UNSW experiment is that creating these two-particle entangled states is tantamount to writing a type of computer code that does not exist in everyday computers. It therefore demonstrates the ability to write a purely quantum version of computer code, using two quantum bits in a silicon microchip -- a key plank in the quest super-powerful quantum computers of the future.

"Passing the Bell test with such a high score is the strongest possible proof that we have the operation of a quantum computer entirely under control," said Morello. "In particular, we can access the purely-quantum type of code that requires the use of the delicate quantum entanglement between two particles."

In a normal computer, using two bits one, could write four possible code words: 00, 01, 10 and 11. In a quantum computer, instead, one can also write and use 'superpositions' of the classical code words, such as (01 + 10), or (00 + 11). This requires the creation of quantum entanglement between two particles.

"These codes are perfectly legitimate in a quantum computer, but don't exist in a classical one," said UNSW Research Fellow Stephanie Simmons, the paper's co-author. "This is, in some sense, the reason why quantum computers can be so much more powerful: with the same number of bits, they allow us to write a computer code that contains many more words, and we can use those extra words to run a different algorithm that reaches the result in a smaller number of steps."

Morello highlighted the importance of achieving the breakthrough using a silicon chip: "What I find mesmerising about this experiment is that this seemingly innocuous 'quantum computer code' - (01 + 10) and (00 + 11) - has puzzled, confused and infuriated generations of physicists over the past 80 years.

"Now, we have shown beyond any doubt that we can write this code inside a device that resembles the silicon microchips you have on your laptop or your mobile phone. It's a real triumph of electrical engineering," he added.

###

In addition to the team lead by Morello, the work was supported by Professor Andrew Dzurak and his team at UNSW, as well as collaborators from the University of Melbourne and Japan's Keio University.

News Release Source : Quantum computer coding in silicon now possible

Image Credit : UNSW

Australian Researchers Design a Full-Scale Architecture for a Quantum Computer in Silicon

Australian scientists design a full-scale architecture for a quantum computer in silicon

Researchers at UNSW and the University of Melbourne have designed a 3D silicon chip architecture based on single atom quantum bits, providing a blueprint to build a large-scale quantum computer.

UNIVERSITY OF NEW SOUTH WALES

Sydney, 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.

[caption id="attachment_687" align="aligncenter" width="695"] This picture shows 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.[/caption]

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 quantum bits 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 inScience 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.

"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.


About the video - Australian researchers have figured out a way to deal with errors in quantum computers, giving them the essential architecture that may help this team become the first to build a functioning quantum computer in silicon.

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 qubits, required for a full-scale quantum processor."

News Release Source :  Australian scientists design a full-scale architecture for a quantum computer in silicon

Image Credit : UNSW Australia

Australian Teams Set New Records for Silicon Quantum Computing

Australian teams set new records for silicon quantum computing

UNSW Newsroom
13 October 2014

Two research teams working in the same laboratories at UNSW Australia have found distinct solutions to a critical challenge that has held back the realisation of super powerful quantum computers.

[caption id="attachment_445" align="aligncenter" width="500"] Australian Teams Set New Records for Silicon Quantum Computing[/caption]

The teams created two types of quantum bits, or "qubits" – the building blocks for quantum computers – that each process quantum data with an accuracy above 99%. The two findings have been published simultaneously today in the journal Nature Nanotechnology.

"For quantum computing to become a reality we need to operate the bits with very low error rates," says Scientia Professor Andrew Dzurak, who is Director of the Australian National Fabrication Facility at UNSW, where the devices were made.

"We've now come up with two parallel pathways for building a quantum computer in silicon, each of which shows this super accuracy," adds Associate Professor Andrea Morello from UNSW's School of Electrical Engineering and Telecommunications.



The UNSW teams, which are also affiliated with the ARC Centre of Excellence for Quantum Computation & Communication Technology, were first in the world to demonstrate single-atom spin qubits in silicon, reported in Nature in 2012 and 2013.

Now the team led by Dzurak has discovered a way to create an "artificial atom" qubit with a device remarkably similar to the silicon transistors used in consumer electronics, known as MOSFETs. Post-doctoral researcher Menno Veldhorst, lead author on the paper reporting the artificial atom qubit, says, "It is really amazing that we can make such an accurate qubit using pretty much the same devices as we have in our laptops and phones".

Meanwhile, Morello's team has been pushing the "natural" phosphorus atom qubit to the extremes of performance. Dr Juha Muhonen, a post-doctoral researcher and lead author on the natural atom qubit paper, notes: "The phosphorus atom contains in fact two qubits: the electron, and the nucleus. With the nucleus in particular, we have achieved accuracy close to 99.99%. That means only one error for every 10,000 quantum operations."

Dzurak explains that, "even though methods to correct errors do exist, their effectiveness is only guaranteed if the errors occur less than 1% of the time. Our experiments are among the first in solid-state, and the first-ever in silicon, to fulfill this requirement."

The high-accuracy operations for both natural and artificial atom qubits is achieved by placing each inside a thin layer of specially purified silicon, containing only the silicon-28 isotope. This isotope is perfectly non-magnetic and, unlike those in naturally occurring silicon, does not disturb the quantum bit. The purified silicon was provided through collaboration with Professor Kohei Itoh from Keio University in Japan.

The next step for the researchers is to build pairs of highly accurate quantum bits. Large quantum computers are expected to consist of many thousands or millions of qubits and may integrate both natural and artificial atoms.

Morello's research team also established a world-record "coherence time" for a single quantum bit held in solid state. "Coherence time is a measure of how long you can preserve quantum information before it's lost," Morello says. The longer the coherence time, the easier it becomes to perform long sequences of operations, and therefore more complex calculations.

The team was able to store quantum information in a phosphorus nucleus for more than 30 seconds. "Half a minute is an eternity in the quantum world. Preserving a 'quantum superposition' for such a long time, and inside what is basically a modified version of a normal transistor, is something that almost nobody believed possible until today," Morello says.

"For our two groups to simultaneously obtain these dramatic results with two quite different systems is very special, in particular because we are really great mates," adds Dzurak.

The quantum bit devices were constructed at UNSW at the Australian National Fabrication Facility, with support from researchers at the University of Melbourne and the Australian National University. The research was funded by: the Australian Research Council, the US Army Research Office, the NSW Government, UNSW Australia and the University of Melbourne.

 

News Release Source : Australian teams set new records for silicon quantum computing

Image Credit : UNSW