ã€Chinese instrument network instrument research and development】 Recently, the experimental group led by Professor Du Jiangfeng, a professor at the University of Science and Technology of China and the academic collaborator of Yale University, Jiang Liang, used diamond spin as a quantum simulator and measured it for the first time in the world. Topology number. The research results were published on the August 4th "Physical Review Letters" in the form of "Editor's Recommendations" [Phys. Rev. Lett. 117, 060503 (2016)].
The topological number can be used to characterize a special kind of phase change—topological phase change. This kind of phase change cannot be explained by the Landau symmetry breaking theory. Since the quantum Hall effect was discovered, many topological phases have been theoretically predicted and experimentally verified. However, directly measuring the number of topologies in experiments is still a challenge. At present, most of the topological systems are difficult to prepare experimentally. A feasible research method is to simulate it with another controllable quantum system. If the Hamiltonian of the quantum simulator is regulated to be completely consistent with the topology, then all the information of the topology can be extracted by the quantum simulator.
Previously, researchers have used superconducting quantum circuits to simulate topological systems and successfully measured the number of atoms, but their measurement needs to integrate on a continuous space. Due to the limitation of experimental conditions, only a limited number of physical quantities can be detected. Therefore, this measurement method often has errors. Very large, can not give the number of discrete topologies. Du Jiangfeng's research group and collaborators adopted the quantum system of nitrogen-vacancy defects in diamonds. Through well-designed microwave and radio frequency pulses, the Hamiltonian of the topological system in different phase spaces was completely reconstructed, and the discrete measurements were accurately measured. The number of topologies and clear topological phase transitions were observed.
This experimental result lays the foundation for the wide application of the quantum simulator based on the diamond system. By coupling multiple nitrogen-vacancy defects, a scalable quantum simulator can be constructed. By precisely controlling individual spins, more complex topological systems can be modeled, and of course other interesting quantum systems can also be studied. Compared to building a general-purpose quantum computer, quantum simulators are expected to enter the practical stage. For some complex materials systems, there are technical challenges in the experimental preparation, and classic computers are powerless. At this time, the use of quantum simulators has very important practical significance.
In addition, the research team led by Du Jiangfeng used the similar spin quantum control technology to test for the first time a kind of measurement-based Heisenberg uncertainty relation based on statistical distance. The research results are also published in the Physical Review Letters [Phys. Rev. Lett. 116, 160405 (2016)]. Phys.org, a science and technology news website, reported that "this work provides a deeper understanding of Heisenberg's original idea of ​​uncertainty and has potential practical applications."
The above research was supported by the National Natural Science Foundation of China, the Ministry of Science and Technology, the Chinese Academy of Sciences and the Ministry of Education.
(Original title: China University of Science and Technology uses quantum simulation technology to achieve direct measurement of the number of topologies)
Previously, researchers have used superconducting quantum circuits to simulate topological systems and successfully measured the number of atoms, but their measurement needs to integrate on a continuous space. Due to the limitation of experimental conditions, only a limited number of physical quantities can be detected. Therefore, this measurement method often has errors. Very large, can not give the number of discrete topologies. Du Jiangfeng's research group and collaborators adopted the quantum system of nitrogen-vacancy defects in diamonds. Through well-designed microwave and radio frequency pulses, the Hamiltonian of the topological system in different phase spaces was completely reconstructed, and the discrete measurements were accurately measured. The number of topologies and clear topological phase transitions were observed.
This experimental result lays the foundation for the wide application of the quantum simulator based on the diamond system. By coupling multiple nitrogen-vacancy defects, a scalable quantum simulator can be constructed. By precisely controlling individual spins, more complex topological systems can be modeled, and of course other interesting quantum systems can also be studied. Compared to building a general-purpose quantum computer, quantum simulators are expected to enter the practical stage. For some complex materials systems, there are technical challenges in the experimental preparation, and classic computers are powerless. At this time, the use of quantum simulators has very important practical significance.
In addition, the research team led by Du Jiangfeng used the similar spin quantum control technology to test for the first time a kind of measurement-based Heisenberg uncertainty relation based on statistical distance. The research results are also published in the Physical Review Letters [Phys. Rev. Lett. 116, 160405 (2016)]. Phys.org, a science and technology news website, reported that "this work provides a deeper understanding of Heisenberg's original idea of ​​uncertainty and has potential practical applications."
The above research was supported by the National Natural Science Foundation of China, the Ministry of Science and Technology, the Chinese Academy of Sciences and the Ministry of Education.
(Original title: China University of Science and Technology uses quantum simulation technology to achieve direct measurement of the number of topologies)