Quantum researchers Dominic Williamson and Nouédyn Baspin from the University of Sydney have introduced an innovative way to handle errors that come up while quantum computers are running.
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Their innovative theoretical approach aims to boost the reliability of quantum information storage while substantially cutting down the physical computing resources required to form ‘logical qubits’ (quantum units capable of performing calculations). This advancement brings us closer to a more compact and efficient "quantum hard drive."
There remain significant barriers to overcome in the development of a universal quantum computer. One of the biggest is the fact we need to use most of the qubits – quantum switches at the heart of the machines – to suppress the errors that emerge as a matter of course within the technology. Our proposed quantum architecture will require fewer qubits to suppress more errors, liberating more for useful quantum processing.
Dr. Dominic Williamson, Study Lead Author, University of Sydney Nano Institute
This research presents a three-dimensional framework at the core of their design, enabling quantum error correction across two dimensions. Unlike current architectures, which also use a 3D qubit layout but correct errors in only one dimension along a single line, this model allows for correction in multiple directions.
Error correction occurs through coding embedded in the lattice of qubits, essentially a structured network of these quantum switches. The goal is to minimize errors with the least possible use of physical qubits, optimizing for both error suppression and efficient processing.
Current 3D codes in a block of dimensions L × L × L can only manage L errors. Our codes can handle errors that scale like L2 (L × L) – a significant improvement.
Dr. Dominic Williamson, Study Lead Author, University of Sydney Nano Institute
For over a decade, it has been understood that a 3D quantum error correction architecture (L x L x L) had an upper limit of L x L in error management. Yet, no effective codes had been developed to achieve this potential until now.
This means that we have discovered new states of quantum matter in three dimensions that have properties never seen before.
Nouédyn Baspin, PhD Student and Study Co-Author, University of Sydney Nano Institute
Quantum computers have the potential to tackle complex problems beyond classical computing’s capabilities, but building practical quantum systems requires robust error correction methods. Traditional approaches, like the surface code, have limitations in scaling and efficiency.
Williamson and Baspin’s research introduces a unique 3D architecture that corrects quantum errors within 2D layers. Utilizing this three-dimensional topological code, they show that optimal scaling can be achieved while lowering the number of required physical qubits—a vital step for scalable quantum computers.
This reduction in qubit overhead supports the development of a more compact "quantum hard drive" for reliable quantum information storage.
This advancement could help transform the way quantum computers are built and operated, making them more accessible and practical for a wide range of applications, from cryptography to complex simulations of quantum many-body systems.
Stephen Bartlett, Professor, Quantum Theorist and Director, University of Sydney Nano Institute
Journal Reference:
Williamson, D. J., & Nouédyn Baspin. (2024) Layer codes. Nature Communications. doi.org/10.1038/s41467-024-53881-3.