Recently, a research team composed of Pan Jianwei, Lu Chaoyang, and Liu Naile of the Institute of Quantum Information and Quantum Science and Technology Innovation of the Chinese Academy of Sciences at the University of Science and Technology of China, in cooperation with the Shanghai Institute of Microsystems and Information Technology of the Chinese Academy of Sciences and the National Parallel Computer Engineering Research Center, successfully built a 255-photon quantum computing prototype "Jiuzhang-3", once again setting a new world record for the technical level of optical quantum information and the superiority of quantum computing.
Researchers have designed new photon detection methods for space-time demultiplexing and constructed high-fidelity quasi-photon number-resolvable detectors, improving the level of photon manipulation and quantum computing complexity. According to the publicly announced optimal classic accurate sampling algorithm, the speed of "Jiuzhang-3" in processing Gaussian Bose sampling is one million times higher than that of the previous generation "Jiuzhang-2". The most complex sample processed by "Nine Chapter 3" in one millionth of a second would take the current most powerful supercomputer "Frontier" more than 20 billion years. This achievement further consolidates my country's international leading position in the field of optical quantum computing.
△Schematic diagram of experimental device
Quantum computing is a new computing paradigm in the post-Moore era. It has ultra-fast parallel computing capabilities in principle. It is expected to use specific quantum algorithms to achieve exponential acceleration compared to classical computers in some problems of great social and economic value. Therefore, developing quantum computers is one of the biggest challenges at the forefront of current world science and technology.
To this end, the international academic community has formulated a three-step development route. Among them, the first step is to achieve "quantum computing superiority", that is, through high-precision quantum control of nearly a hundred qubits, solving specific problems shows computing power that is unmatched by supercomputers. At the same time, in the process, scalable quantum control technology was developed to provide a technical foundation for the development of universal quantum computers with fault-tolerant capabilities.
In 2020, the University of Science and Technology of China team successfully built the 76-photon "Nine Chapters" optical quantum computing prototype, achieving the "quantum computing superiority" of an optical system internationally for the first time, and overcoming the loophole in the Google experiment that quantum superiority depends on the number of samples. In 2021, the University of Science and Technology of China team further successfully developed the 113-photon phase-programmable "Jiuzhang-2" and 56-bit "Zuchong-2" quantum computing prototypes, making my country the only country that has achieved "quantum computing superiority" in both optical and superconducting technology routes.
△International competitive situation of optical quantum computing
Through a series of innovations, the University of Science and Technology of China team achieved the ability to manipulate 255 photons for the first time, greatly improving the complexity of optical quantum computing and processing Gaussian Bose sampling one million times faster than the "Jiuzhang-2". On the basis of building the "Nine Chapters" series of optical quantum computing prototypes, the research team also revealed the mathematical connection between Gaussian Bose sampling and graph theory, and completed the solution of two types of graph theory problems with practical value, such as dense subgraphs, which is 180 million times faster than the precise simulation of classical computers. In addition, it demonstrated the advantages of unconditional multi-photon quantum precision measurement for the first time in the world.