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An Undergraduate Student's Homework Could Solve A Major Problem With Quantum Computers


Stephen Luntz

Stephen has a science degree with a major in physics, an arts degree with majors in English Literature and History and Philosophy of Science and a Graduate Diploma in Science Communication.

Freelance Writer

quantum surface

Pablo Bonilla Ataides (at board) explaining some of his work to Dr Ben Brown (left). Bonilla made a breakthrough that could overcome a major obstacle to quantum computing. Image Credit: University of Sydney

For more than twenty years, scientists have been buzzing about the potential of quantum computers – which, in theory, could answer instantaneously many questions that take existing computers days of computing time. Progress has been rather slower than the hype. Now, however, one of the obstacles may have been greatly reduced by a second-year physics student getting his first experience of working on real-world problems. His solution has been snapped up by Amazon Web Service (AWS) among others.

Quantum computing is bedeviled by the number of errors generated in the process of calculating. These errors can be reduced, but never eliminated, requiring techniques to identify and correct them.


“In second-year physics I was asked to look at some commonly used error correcting code to see if we could improve it. By flipping half of the quantum switches, or qubits, in our design, we found we could effectively double our ability to suppress errors,” Pablo Bonilla Ataides of the University of Sydney said in a statement.

A paper built on that solution has now been published in Nature Communications

Dr Ben Brown is that paper's senior author. He told; “It's impossible to make qubits perfect – to do so they would need to operate at temperatures of absolute zero, and there are always errors with lab equipment anyway.” Consequently, errors are far more common than for traditional semi-conductor computers. Instead, scientists are seeking ways to make qubits act collectively so they serve as checkers for each other, revealing where errors have occurred.

“At Sydney we had been working on this problem for a while.” Brown said. Bonilla applied to join a program where second-year students joined projects. Impressed by his exam results, the program's head let him in. “We sent Pablo off to try something and he came back with some code and simulations that showed great results,” Brown continued.


In Brown's words, Bonilla; “Really wanted to see it through to the end.”

This turned out to be considerably further than anyone expected. In addition to publication in a prestigious journal, the work has been taken up by major research laboratories. Both AWS and Yale University turned out to already be working on qubits particularly suited to the theoretical process Bonilla had proposed. “This research surprised me,” Dr Earl Campbell of AWS said. ”I was amazed that such a slight change to a quantum error correction code could lead to such a big impact in predicted performance.”

Brown told IFLScience both institutions are looking to implement the idea in practice.

Nevertheless, Brown cautions there is a long way to go before quantum computing achieves widespread application. “People are very excited about an experiment in 2019,” he told IFLScience, “But that is still really just a quantum abacus.”


Switching analogies, Brown compared quantum computers to the Wright Brothers' plane. “Experimentalists are producing the strong, light-weight materials to build the plane, and we've just come up with a more aerodynamic design for the wings that have more lift.”


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