講座名稱：自然軌道重正化群（NORG）和動力學平均場理論（DMFT）

講座人：盧仲毅 教授

講座時間：4月25日16:00

講座地點：北校區(qū)西大樓三區(qū)412報告廳

講座人介紹：

盧仲毅，中國人民大學理學院物理系主任、材料計算與物質模擬團隊學科責任教授和召集人、中國人民大學特聘教授。1988年于北京郵電大學應用物理系獲學士學位，1991年于中國科學院理論物理研究所獲碩士學位，1996年于意大利國際高等研究院(SISSA)獲博士學位。主要從事電子結構計算方法及其并行化算法以及分子動力學模擬方法的研究以及這些方法在實際系統(tǒng)中的應用。曾獲國家自然科學二等獎。

講座內(nèi)容：

There are many novel quantum phenomena in strongly correlated electronic materials. How to understand and characterize them has always been one of the central topics in condensed matter physics. The DFT+DMFT electronic structure calculation method is considered to be the most powerful and promising method for studying strongly correlated electronic materials, which combines the first-principles electronic structure calculation based on the density functional theory (DFT) and the dynamical mean field theory (DMFT). Nevertheless, the DFT+DMFT calculation method now suffers the sign problem with its quantum Monte Carlo impurity solver, which seriously hinders the development and application of DFT+DMFT. On the other hand, the quantum renormalization group (RG) procedure is one of the most important and accurate approaches for studying interacting many-electron correlated systems, 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 rather than exponential computational cost in the number of electron bath sites to solve low-energy states of a quantum impurity model. Moreover, the NORG 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. This makes the NORG be a natural impurity solver to dynamical mean field theory.

主辦單位：物理與光電工程學院