World-record quantum computing

A type of building block for quantum computers, a world-record result for reducing errors in semiconductor electron 'spin quays', has been achieved using the theoretical work of quantum physicists in the Sydney Nano Institute and School of Physics.

Experimental results by engineers of New South Wales demonstrated an error rate of 0.043 percent as compared to any other electron spin.

Joint research paper by Sydney and UNSW teams was published this week in Nature Electronics and is the cover story of the magazine for April.

"Quantum computers need to reduce errors before they can be transformed into useful machines," said Professor Stephen Bartlett, a related author of the paper.

"Once they work on a large scale, the quantum computer can fulfill its great promise to solve problems beyond the capabilities of its biggest supercomputer, thus giving humanity chemistry, drug design and problems in the industry. May help to solve. "

There are many types of quantum bits or clubs, ranging from trapped ions, people using superconducting loop or photon.

A 'spin qubit' is a quantum bit that encodes information based on the quantitative magnetic direction of a quantum object, such as an electron.

Australia and Sydney are emerging as a global leader in Quantum Technology, in particular.

The recent announcement of funding for the establishment of the Sydney Quantum Academy underlines the big opportunity to create a quantum economy based on the world's largest concentration of quantum research groups in Sydney in Australia.

No practice without theory

While the recent focus in quantum computing has been progressing in hardware, none of this progress is possible without the development of quantum information theory.

The University of Sydney Quantum Doctrine Group, led by Professor Stephen Bartlett and Professor Steven Flammia, is one of the world powerhouses of quantum information theory, which allows engineering and experimental teams around the world, the hard work needed to ensure quantum computing Physical progress does. Reality

The work of the Sydney Quantum Theory Group was essential for a world-record outcome published in Nature Electronics.

Professor Bartlett said: "Because the error rate was so small, the UNSW team needed some very sophisticated methods to be able to detect errors.

"With such a low error rate, we needed to run the data that went on days and days to collect data to show a timely error."

Professor Bartlett said that once errors have been identified, they need to be characterized, finished and rearranged.

"The group error of Steve Flamia is the leader of the world in the theory of characterization, which was used to achieve this result," he said.

Flammia Group has demonstrated the first time to improve the quantum computer by using the code designed to detect and discard errors in logic gates or switch errors using the IBM Q Quantum computer.

Professor Andrew Dzurak, who led the UNSW research team, said: "It is invaluable for working with professors Bartlett and Flamia and his team, which is to help us understand those types of errors that we have in our UNSW Silicon-CMOS watches in the cabin.

"Our chief experimentalist, Henry Yang, worked closely with him to achieve this remarkable loyalty of 99.957 percent, showing that we now have the most accurate semiconductor qubit in the world."

Professor Bartlett said that the probability of Henry Yang's world-record achievement will last long. He said that now the UNSW team and others will work on the creation of two levels and high-level arrays in silicon-CMOS.

Quantum computers that work fully will need millions, if not for billions, to operate. To scale such devices, designing low error qubits is now an important step.

Professor Raymond Laflamme is the President of Quantum Information at Waterloo University in Canada and was not involved in the study.

He said: "As quantum processors become more common, an important tool for evaluating them has been developed by the Bartlett Group at the University of Sydney, which gives us the accuracy of quantum gates and makes the physicists inconsistent and different Gives the ability of compatible errors, which lead to unprecedented control of Quantum. "

Global impact

At the Niels Bohr Institute in Copenhagen, a joint University of Sydney-UNSW results immediately after a paper by the same quantum theory team with experimentalists.

This result allows the distant exchange of information between electrons, published in Nature Communications, through an intermediary, improving the possibilities for scale-up architecture in spin-quant Quantum computers.

The result was important because it allows the distance between quantum dots to be sufficient for integration into more traditional microelectronics.

This achievement was a joint effort by physicists in Copenhagen, Sydney, and Purdue in the United States.

Professor Bartlett said: "The main problem is that Quantum Dots must be ridiculously close to the nanometer - to interact with them.

But at this distance they interfere with each other, to make useful calculations Tune the device becomes very difficult. "

The solution was that the confused electrons be allowed to mediate their information through a 'pool' of electrons so that they would be different.

They said: "This is like a bus - a big arbitrator which allows for the movement of distances far away.

If you can allow more spin interaction, then the quantum architecture can go into a two-dimensional layout."

Ferdinand Kuemmeth, associate professor of Niels Boeh Institute, in Copenhagen said: "We found that a large, long quantum dot between the left dots and right dots mediates a consistent swap of spin states, within a second billion, sometimes Also without moving electrons. Of their dots.

Professor Bartlett said: "The thrill that I find about this result is in the form of a theoretical, it frees us from the constrained geometry of a qubit which is only dependent on its immediate neighbors."

Office of the Global Engagement

The history of this experiment goes to America's Intelligence Advanced Research Projects Activity (IARPA) program for a decade, led by Professor Charlie Marcus, who was a co-author before moving to Copenhagen, who was then at Harvard.

Professor Bartlett said: "We all went to Copenhagen for a workshop in 2018 to work on this problem." Thomas Evans, the co-author of the paper, was there for two months, supported by the office for global engagement. Ogee also supported Dr. Arne Grismo, who was working on another project. "

He said that till we got OGE funding, the experiment and our discussion were well advanced.

But this was the workshop and the money for that which allowed the Sydney team to go to Copenhagen on the basis of this result to plan next-generation experiments.

Professor Bartlett said: "This method allows us to separate quantum dots a bit, which makes it easier to tune them apart and work together.

"Now when we have this mediator, we can start planning for a two-dimensional array of these pairs of quantum dots."

World-record quantum computing