Australian Researchers of UNSW Sydney have proven another milestone for Quantum Computing by running at 99% Accuracy

The discovery, conducted by UNSW Sydney, lays the door for huge silicon-based quantum processors to be manufactured and used in the real world. The AUSMURI project by the UNSW-UTS consortium aimed to reduce overall quantum gate errors through utilizing multi-qubit systems. Researchers in Australia have successfully demonstrated that near-error-free quantum computing is attainable, this led to a clear path for the development of silicon-based quantum devices that are compatible with current semiconductor manufacturing technologies.

Today’s publication shows our operations were 99 per cent error-free. When the errors are so rare, it becomes possible to detect them and correct them when they occur. This shows that it is possible to build quantum computers that have enough scale, and enough power, to handle meaningful computation.

Professor Andrea Morello of UNSW

The team aims to build what’s called a ‘universal quantum computer’ that is universal and won’t be specific to one application. This is a significant step forward in the development of high-fidelity quantum processors in silicon.

The UNSW and Delft teams used a complex technology called gate set tomography, which was created at Sandia National Laboratories in the United States and made widely available to the research community, to certify the performance of their quantum computers.

Prof. Morello’s work is one of three in Nature today that independently indicate that robust, dependable quantum computing in silicon is now possible. The breakthrough is featured on the journal’s front cover.

  • With a three-qubit system consisting of an electron and two phosphorous atoms implanted in silicon through ion implantation, Morello et al obtained one-qubit operation fidelity of up to 99.95% and two-qubit fidelity of 99.37%.
  • Using electron spins in quantum dots produced in a stack of silicon and silicon-germanium alloy (Si/SiGe), a Delft team lead by Lieven Vandersypen achieved 99.87 percent one-qubit and 99.65 percent two-qubit fidelities.
  • In a two-electron system using Si/SiGe quantum dots, a RIKEN team led by Seigo Tarucha achieved 99.84 percent one-qubit and 99.51 percent two-qubit fidelities.

In the quantum world, 35 seconds is an eternity…To give a comparison, in the famous Google and IBM superconducting quantum computers the lifetime is about a hundred microseconds – nearly a million times shorter.

Professor Andrea Morello of UNSW

Prof. Morello had previously demonstrated that he could preserve quantum information in silicon for 35 seconds, due to the extreme isolation of nuclear spins from their environment. However, separating the qubits made it appear as if they couldn’t communicate with one another, which is required to execute genuine computations.

Researchers from UNSW, the University of Melbourne (for ion implantation), the University of Technology Sydney (for the initial use of the GST method), Sandia National Laboratories (invention and improvement of the GST method), and Keio University collaborated on the UNSW-led article (supply of the isotopically purified silicon material).

All existing computers deploy some form of error correction and data redundancy, but the laws of quantum physics pose severe restrictions on how the correction takes place in a quantum computer.

You typically need error rates below 1 per cent, in order to apply quantum error correction protocols. Having now achieved this goal, we can start designing silicon quantum processors that scale up and operate reliably for useful calculations.

Professor Andrea Morello of UNSW