Chinese scholars reveal the unique quantum properties of “quantum Cheshire cat”

The thought experiment of “Schrodinger’s cat” in quantum mechanics has been well known in the academic circles, and in recent years the international scientific community has put forward a cutting-edge concept called “quantum Cheshire cat”. Recently, the team of Guo Guangcan academicians of The University of Science and Technology of China, in cooperation with Nankai University scholars, realized for the first time the polarization of photons and their ontobody, and then realized the contactless exchange of two photon polarizations, which revealed the unique quantum characteristics of the “quantum Cheshire cat” and deepened people’s understanding of the basic problem of physics.

In the macro-classical world, the physical properties of an object, such as mass and volume, are inseparable from the object itself, but are different in the micro quantum world. A theoretical study in the international scientific community in 2013 showed that the physical properties of microscopic particles (such as electron charge and spin, photon spolarization, etc.) can be separated from their ontobody, a phenomenon that several well-known scholars have named “Quantum Cheshire Cat”.

Cheshire Cat is a smiling cat in the children’s literary book Alice in Wonderland, whose body can disappear from empty air, but whose smile is still hanging in the air. The international scientific community has observed the separation of particle properties from their ontotoin in the interference experiments of neutrons and photons, but more complex experiments are needed to demonstrate the unique quantum effects of quantum Cheshire cats.

Recently, Li Chuanfeng, Xu Jinshi, Xu Xiaoye and others in the Guo Guangcan academician team of the Chinese University of Science and Technology, in cooperation with Professor Chen Jingling of Nankai University, used the double photonic system for the first time to exchange two “quantum Cheshire cats” for smiling faces.

Using a new method of micro-disturbing the system, they solved the problem of extracting weak values of multibody quantum systems, and prepared a double photon super-entanglement state to obtain the path of photons and the weak value of polarization observations. The experiment observed that both photons were separated by polarization properties and photon ontobody, and each obtained the polarization of another photon, enabling the contactless smiley swap between two “quantum Cheshire cats”.

The results demonstrate the flexible relationship between matter and its physical properties in the quantum world, deepening the understanding of the basic physics of “what is physical reality”. On the other hand, the introduction of microperturbation to obtain weak values will also become a powerful tool for studying quantum physics.

The study, published recently by Nature Communications, an international authoritative academic journal, was described by reviewers as “a milestone” and an important development in understanding the underlying problems of quantum mechanics.