One of the most important and accurate approaches for studying interacting many-electron correlated systems is the quantum renormalization group (RG) procedure, upon which we propose a new concept in the framework of natural orbitals so that we can generalize the RG into general orbital space, namely natural orbitals renormalization group (NORG). We show that the NORG takes a polynomial ($O(N_{bath}^3)$) rather than exponential computational cost in the number of electron bath sites and it can work on a quantum impurity model with any lattice topological structure. Actually, the effectiveness of the NORG is basically irrespective of a model's topological structure. Thus, the NORG is naturally appropriate for studying quantum cluster-impurity model. By using the NORG, we have recently solved the two-impurity Kondo problem, a long-standing problem in which there is the competition between the two opposite tendencies in the formation of a singlet ground state, driven respectively by the single-ion Kondo effect with conduction electrons to screen impurity spins and the RKKY interaction between the two impurities to directly form impurity spin singlet. The NORG is a natural impurity solver to dynamical mean field theory, which I will also introduce in this talk.

个人简介：卢仲毅于 1996年在意大利国际高等研究院(SISSA)获得凝聚态物理学哲学博士学位。毕业后，先后在美国能源部Ames国家实验室、 Vanderbilt大学物理系和Oak Ridge国家实验室计算机科学和数学部工作。2005年1月聘为中国科学院理论物理研究所研究员和博士生导师。2007年1月聘为中国人 民大学教授、物理系材料计算与物质模拟团队学科责任教 授和召集人。主要从事电子结构计算方法及其并行化算法以及分子动力学模拟方法的研究以及这些方法在实际系统中的应用。