The Chinese keep their word and demonstrate quantum superiority on a larger matrix
Chinese scientists have announced that they have kept their word given last December and improved their optical system so that it can Quantum Gaussian boson sampling on a 144x144 matrix. In doing so, they confirmed that their quantum computer had the Quantum superiority has achieved, ie it is able to perform calculations that classic computers cannot perform in a reasonable time. We have already heard of the achievement several times Quantum superiority heard. This is what Google claims in 2019, for example.
Image source: Pixabay; Article Physical Review Letters
However, each time the experts objected to the algorithms used. This time, the Chinese assure us, there will be no such objections. The work of the scientists of the National Physical Sciences Laboratory at the Chinese University of Science and Technology in Hefei was directed by Jian-Wei Pan. The aim of the work was to create a quantum computers to build the probability of a certain outcome at the outcome of a Quantum circuit calculated. Classical computers can solve such a task without major problems, provided that there are only a few output and input points of such a circuit. However, when there are more of them, the time it takes to perform calculations with classic computers becomes so long that it becomes meaningless to perform the calculations. The team introduced Gaussian boson sampling (GBS) .
How does this work? Imagine an optical system with many inputs and outputs. We then let in individual photons, which on their way to the exit on various optical components such as Beam splitter or hit mirrors. Our math problem is to determine which Photons will appear at the exit. We can imagine such a system as a matrix that transforms the configuration of the photons admitted at the entrance into an output configuration. Determining the initial configuration is very difficult even with a small matrix of manifolds and mirrors. As there are more and more entry and exit points, it is extremely difficult to determine the outcome of such an experiment.
Last December, the Chinese used a GBS that consisted of 100 input and 100 output points. At the time, they reported that their system did the calculation in about 200 seconds. The Chinese supercomputer Sunway TaihuLight, the fourth most powerful computer in the world at that time, would have taken ... about 2,5 billion years. After the successful experiment, the researchers announced that they had improved GBS to the point that they were experimenting with a 144x144 matrix could perform.