强关联量子杂质体系的精确模拟  

Precise simulation of strongly correlated quantum impurity systems

作　　者：郑晓 Xiao Zheng(Hefei National Laboratory for Physical Sciences at the Microscale,University of Science and Technology of China,Hefei 230026,China)

机构地区：[1]中国科学技术大学,合肥微尺度物质科学国家研究中心,合肥230026

出　　处：《科学通报》2018年第33期3412-3418,共7页Chinese Science Bulletin

基　　金：国家重点研发计划(2016YFA0400900;2016YFA0200600);国家自然科学基金(21573202);中国科学技术大学重要方向培育基金(2340000074)资助

摘　　要：对复杂凝聚态体系中的局域量子态的精确描述,以及对量子态在外场、环境调控下的响应与演化机制的深刻理解,对量子功能材料与器件的构筑与设计有着重要的基础性意义.然而,如何精确刻画复杂材料体系中的量子相干、关联、纠缠等特性,对理论研究而言是个传统难题.本文从全新的视角,即"开放量子体系"的角度来研究复杂凝聚态体系中的量子态.简要介绍了近年来我们基于严格的量子耗散理论发展得到的级联运动方程方法,以及该方法在实验高度关注的强关联量子杂质体系的计算模拟研究方面的应用.In recent years, nano-sized systems involving local charge or spin states have received wide interests because of their potential application in emerging fields such as quantum information and quantum computation. For instance, organometallic molecular complexes may serve as building blocks of quantum storage devices, because the spin-unpaired d or f electrons at transition metal centers may be employed to construct spin qubits. Moreover, if the system contains strong electron-electron interaction, the involving local quantum states are subject to prominent electron correlation effects（such as the Kondo effect）. Theoretically, spatially confined nano-systems are often described by quantum impurity models. Thus the accurate prediction of the intrinsic properties of quantum impurity systems and the deep understanding on the response and evolution of local quantum states under external fields or in dissipative environment are fundamentally important for the design and fabrication of quantum devices. The accurate characterization of quantum coherence, correlation, and entanglement in quantum impurity systems remains a great challenge. Enormous efforts have been made to achieve this goal. A variety of theoretical methods have been developed, including the numerical renormalization group method, the quantum Monte Carlo method, and many others. However, all the existing methods are subject to certain limitations regarding accuracy or efficiency. Therefore, we choose to view this problem from a new perspective—the perspective of open quantum systems. Over the past decade, we have developed a formally exact quantum dissipation theory, the hierarchical equations of motion（HEOM） theory, for fermionic open systems. The HEOM theory captures the combined effects of system-environment dissipation, many-body interaction, and non-Markovian memory in a nonperturbative manner. It is capable of addressing static and dynamic responses of system observables in both equilibrium and nonequilibrium situations. We have implement

关 键 词：强关联体系 开放量子体系 级联运动方程 近藤效应 分子磁体 

分 类 号：O413[理学—理论物理]