International first! Chinese scientists have made a major breakthrough

Quantum simulation experiments have made a major breakthrough. The Chinese Academy of Sciences held a press conference in Beijing on the 6th. Reporters learned from the press conference that using the "bottom-up" quantum simulation method, the team of Academician Pan Jianwei of the University of Science and Technology of China has achieved the fractional quantum anomalous Hall state of photons for the first time in the world. This is an important progress in the field of quantum physics and quantum information science. The relevant research results were published online in the journal Science.

Results Diagram

Image source: Chinese Academy of Sciences official website

The Hall effect refers to the fact that when current passes through a material placed in a magnetic field, the electrons are affected by the Lorentz force, generating a voltage perpendicular to the direction of the current and magnetic field inside the material. This effect was discovered by American scientist Hall in 1879 and is widely used in the field of electromagnetic sensing. The anomalous Hall effect refers to the observation of the related effect in the absence of an external magnetic field.

In traditional research on the quantum Hall effect, a "top-down" approach is used, which usually means that researchers start from existing materials and use the inherent structure and properties of these materials to achieve quantum Hall states. This method requires specific conditions, such as extremely low temperature environments, high-purity two-dimensional materials, and strong magnetic fields. These conditions are often difficult to meet and limit the control and operation of the experiment.

In contrast, artificially constructed quantum systems have clear structures, are flexible and controllable, and are a new paradigm for studying complex quantum states from the bottom up. "The advantage of this method is that it provides greater flexibility and controllability, and researchers can precisely control each component to better understand and manipulate quantum systems." Lu Chaoyang, a co-corresponding author of the paper and a professor at the University of Science and Technology of China, said that this type of technology is called quantum simulation and is an important part of the "second quantum revolution". It is expected to be used in the near future to simulate quantum systems that are difficult to calculate classically and achieve "quantum computing superiority."

"In layman's terms, if the quantum Hall effect is compared to a house, the 'top-down' approach is like renovating and remodeling the existing house, while the 'bottom-up' approach is like starting from a brick and a tile and rebuilding a house completely according to the design drawings," Lu Chaoyang said figuratively.

This time, the research team used a new type of superconducting quantum bit Plasmonium developed independently to successfully realize nonlinear interactions between photons, and further constructed an equivalent magnetic field acting on photons to construct an artificial gauge field, thus realizing the fractional quantum anomalous Hall state of photons for the first time in the world.

Nobel Prize winner in Physics Frank Wilczek spoke highly of the research. He said: "This 'bottom-up' approach is a 'very promising idea' and this is an impressive experiment that takes an important step towards anyon-based quantum information processing."

Reporter Lu Chengkuan and Wu Changfeng

Source: Science and Technology Daily