Pan teams optical quantum computer uses an interferometer in 144 mode to solve the Gaussian boson sampling problems. This gives it a speedup of 1024 times relative to a traditional computer. Credit: Chao-Yang Lu/University of Science and Technology of China via Physics
Two Chinese teams claim to have achieved primacy using their own quantum computers. Both teams published details of their work in Physical Review Letters.
Quantum primacy refers to the ability to perform calculations on computers that aren't possible with conventional computers. Other people use the term "quantum advantage"
Over the years, many teams that work with quantum computers claim to have achieved primacy. However, they have been met with suspicion due to questions about the algorithm chosen, which includes the one used by Google. Both teams claim that their computers are perfect and leave no room to doubt.
These new teams were both based at the Hefei National Laboratory for Physical Sciences of the University of Science and Technology of China. Both were led by Jian-Wei Pan (a physicist well-known for his work on quantum entanglement).
Both efforts were aimed at building a quantum computer capable to calculate the output probabilities for quantum circuits. This task is much easier than a conventional computer can do when there are only a few inputs or outputs. It becomes more difficult with increasing numbers until it is impossible to do.
The researchers used a photonic approach to build their first computer. Gaussian boson sampling was used by the team to analyse the output. This case involved output from a 144 mode interferometer. In this scenario, there are 1043 possible outcomes. Researchers claim that their machine could sample the output 1023x faster than a supercomputer. This, they claim, is quantum primacy.
A second attempt was to create a superconductor-based computer capable of computing using 66 qubits. Only 56 were used. The researchers still found that the machine could estimate sample calculations at a rate of 1000 times faster than the fastest supercomputers. This, they claim, proves their primacy.
Explore further Chinese photonic quantum computer demonstrates quantum supremacy
Han-Sen Zhong and colleagues, Phase-Programmable Gaussian Boson Sampleling Using Stimulated squeezed Light, Physical Review Letters (2021). Han-Sen Zhong and colleagues, Phase-Programmable Gaussian Boson Collection Using Stimulated Seezed Light, (2021). DOI: 10.1103/PhysRevLett.127.180502 Yulin Wu et al, Strong Quantum Computational Advantage Using a Superconducting Quantum Processor, Physical Review Letters (2021). DOI: 10.1103/PhysRevLett.127.180501 Journal information: Physical Review Letters
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