A Chinese research team has successfully achieved the world's first "continuous variable" quantum entangled cluster state based on integrated optical quantum chips. The related research results were published in the journal Nature on the 20th. Experts point out that this breakthrough achievement fills the key technological gap in light quantum chips using continuous variable encoding, and lays an important foundation for the large-scale expansion of light quantum chips and their applications in quantum computing, quantum networks, and other fields. Integrated optical quantum chip is an advanced platform that can encode, process, transmit, and store optical quantum information at the micro nano scale. How to achieve large-scale quantum entanglement on photonic quantum chips is an international quantum research challenge. The reviewer of the journal Nature commented that "this work is the first to achieve multi bit continuous variable quantum entanglement on a photonic quantum chip, which is an important milestone in scalable optical quantum information processing." "Quantum entangled cluster states, as a type of multi bit quantum entangled state, are the core resource of quantum information science and have always been a key direction that the international scientific community is striving to overcome. However, for a long time, their deterministic and large-scale preparation has faced enormous experimental difficulties, especially the preparation and verification technology of photonic quantum chips with continuous variable cluster states is still blank internationally," said Wang Jianwei, the corresponding author of the paper and a professor at the School of Physics, Peking University. A research team composed of experts from Peking University and Shanxi University has successfully overcome key technological bottlenecks after years of scientific research and development. They have innovatively developed continuous variable light quantum chip regulation, multi-color coherent pumping and detection technology, achieved deterministic and reconfigurable entangled cluster state preparation, and rigorously experimentally verified the entangled structure of cluster states. Wang Jianwei introduced that quantum bits can be implemented on optical quantum chips through discrete variable encoding and continuous variable encoding methods. To prepare quantum bits with ultra-high fidelity, a single photon based discrete variable encoding method was commonly used in the past. However, the success rate of this method decreases exponentially with the increase of the number of quantum bits. To this end, the team adopted a continuous variable encoding method based on light field to solve the "probability" problem of preparing quantum bits and quantum entanglement, and for the first time achieved the "deterministic" generation of quantum entangled cluster states on chips. Previously, the team also developed a large-scale quantum chip that integrates about 2500 components, and implemented graph theory based quantum computing and information processing functions, providing a scalable, programmable, and highly stable quantum chip core for the development of quantum computers. In recent years, China's quantum computing and quantum communication have been accelerating towards practicality, with related achievements and applications constantly emerging. This is a new breakthrough made by Chinese scientists in the field of integrated optical quantum chip technology Gong Qihuang, an academician of the CAS Member, said that this original achievement provides a new technical path for the preparation and manipulation of large-scale quantum entangled states, and is of great significance in promoting the practical development of quantum computing, quantum networks and quantum simulation. (New Society)