◎ Science and Technology Daily reporter Wu Changfeng
The reporter learned from the University of Science and Technology of China that in the early morning of February 10, the international academic journal "Nature" published three achievement papers by the team of the University of Science and Technology of China online, which reported important progress in quantum simulation based on ultracold atoms and molecules, new electron phases, and protein design.
For the first time, triatomic molecules were synthesized in an ultracold atomic molecular mixture
Pan Jianwei, Zhao Bo, and others cooperated with the Bai Chunli group of the Institute of Chemistry of the Chinese Academy of Sciences to synthesize triatomic molecules for the first time in the mixture of ultracold atoms and molecules, taking an important step towards quantum simulation based on ultracold atomic molecules and the study of ultracold quantum chemistry.
The use of highly controllable ultra-cold quantum gases to simulate complex and difficult-to-calculate physical systems allows for accurate and all-round study of complex systems, thus having a wide range of application prospects in chemical reactions and new material design.
The team observed the Feshbach resonance of atoms and diatomic molecules at ultra-low temperatures for the first time in 2019. Near the Feshbach resonance, the energies of the bound state of the triatomic molecules tend to coincide with the energy of the scattering state, while the coupling between the scattered and bound states is greatly enhanced by resonance. The successful observation of the resonance of atomic molecules Feshbach provides new opportunities for the synthesis of triatomic molecules.
The researchers prepared sodium-potassium ground-state molecules in a single ultra-fine state from an ultra-cold atomic mixture close to absolute zero. Near the Feshbach resonance of potassium atoms and sodium-potassium molecules, the scattered states of atomic molecules and the bound states of triatomic molecules are coupled together by an RF field. They successfully observed the signal of the RF synthesis triatomic molecule on the rf loss spectrum of the sodium-potassium molecule and measured the binding energy of the triatomic molecule near the Feshbach resonance. This achievement opens up a new path for quantum simulation and the study of ultracool chemistry.
Novel electron facies were found in cage superconductors
The team of Chen Xianhui, Wu Tao and Wang Zhenyu discovered a new type of electron hoistine phase in the cage superconductor, which not only provides important experimental evidence for understanding the abnormal competition between charge density waves and superconductivity in the cage structure superconductor, but also provides a new research direction for further studying the interleaved sequence closely related to unconventional superconductivity in the associated electronic system.
Electron hoistine phases are widely present in electronic systems such as high-temperature superconductors and quantum Hall insulators, and there is a close relationship between high-temperature superconductivity, which is considered to be an interweaving sequence associated with high-temperature superconductivity. The theory predicts that the two-dimensional cage system can present novel superconductivity and rich electron ordered state, but for a long time there is a lack of suitable material systems to achieve its associative physics, and the discovery of cage superconductors provides a new research system for the exploration of this direction.
Combining three experimental techniques of scanning tunneling microscopy, nuclear magnetic resonance and elastic resistance, the research team found that before the system enters the superconducting state, the triple modulation charge density wave state will further evolve into a thermodynamically stable electron facade, and determine that the transition temperature is around 35 Kelvin. Interestingly, this new electron-oriented phase has also recently been observed in bilayer angled graphene systems.
Build proteins from scratch to design new methods
Based on the principle of data drive, the team of Professor Liu Haiyan and Associate Professor Chen Quan has opened up a new protein design route from scratch, realized the original innovation of key core technologies in the frontier technology field of protein design, and laid a solid foundation for the design of functional proteins such as industrial enzymes, biomaterials, and biomedical proteins.
At present, almost all proteins that can form stable three-dimensional structures are natural proteins, and their amino acid sequences are naturally evolved over a long period of time. When the structure of a natural protein cannot meet the needs of industrial or medical applications, the structure of a specific functional protein needs to be designed. In recent years, the representative work of protein de novo design in the world has mainly adopted the RosettaDesign method, that is, using natural structural fragments as building blocks to splice to produce artificial structures. However, this method has shortcomings such as single design results and excessive sensitivity to the details of the main chain structure, which significantly limits the diversity and variability of the design main chain structure.
The research team first established the ABACUS model of the amino acid sequence designed for a given backbone structure, and then developed the SCUBA model that can design a new backbone structure from scratch at the amino acid sequence waiting time. Theoretical calculations and experiments have proved that the design of the backbone structure with SCUBA can break through the limitation that only natural fragments can be used to splice to produce a new backbone structure, thereby significantly expanding the structural diversity of the de novo design proteins, and even designing novel structures that are different from known natural proteins. The SCUBA model + ABACUS model forms a complete tool chain for artificial proteins with a completely new structure and sequence from scratch, and is currently the only experimentally validated protein de novo design method outside of RosettaDesign, which complements and complements them. The high-resolution crystal structure of the 9 de novo protein molecules reported this time, 5 of which have novel structures that differ from known native proteins.
Source: Science and Technology Daily The pictures in the article are from the University of Science and Technology of China
Editor: Zhang Shuang
Review: Julie
Final Judgement: Wang Yu