报告摘要

I will talk about an ab initio quantum chemistry framework for faithful simulations of correlated materials and electron-boson coupled systems.The first part includes the density matrix embedding theory (DMET), and its applications to correlated materials and high-temperature superconductors. The method allows for spin SU(2) and particle-number U(1) symmetry-breaking states such that the superconducting orders spontaneously emerge during the self-consistency. We directly computed the superconducting pairing order of several doped cuprate materials and structures. We found that we could correctly capture two well-known trends: the pressure effect, where the pairing order increases with intra-layer pressure, and the layer effect, where the pairing order varies with the number of copper-oxygen layers. In the second part of the talk, I will discuss a canonical transformation-based method for electron-boson coupled problems. The method is applied to several electron-boson coupled systems, including the Hubbard-Holstein model and ab initio systems. We show that the method gives accurate energies and observables comparable to exact diagonalization or DMRG calculations, and allows for large-scale simulations for quantum materials with modest computational cost.

报告人简介

Dr. Zhi-Hao Cui received his bachelor's degree with the highest honors from Peking University in 2017 (under the supervision of Prof. Hong Jiang at Peking University). After that, he obtained his Ph.D. in Theoretical Chemistry from Caltech in 2023 (under the supervision of Prof. Garnet Chan). He is currently a postdoctoral scholar at Columbia University (working with Prof. David Reichman). Dr. Cui's Ph.D. research has been focused on establishing a theoretical framework for simulations of high-temperature superconductors and other strongly correlated quantum materials. In particular, he is the leading author of several high-impact research works, including in the area of ab initio quantum embedding theories (density matrix embedding theory and dynamical mean-field theory), and the first fully ab initio simulation of the magnetic and superconducting properties of high-temperature superconductors. The methods and software that he developed and contributed to have been used by hundreds of research groups in academia and industry. His previous research includes development of improved density functionals and their application to solar-energy conversion materials, and to study catalysis at surface and interfaces. He is now working on electron-boson coupled systems, such as polariton and polaron chemistry. He has published more than 30 scientific papers with an H-index of 18. Dr. Cui has received many awards and distinctions, including the Herbert Newby McCoy Award from Caltech, the Chemical Computing Group Excellence Award for Graduate Students from ACS, the Eddleman Graduate Research Fellowship, the Caltech C Fellowship, and Weldon Brown Fellowship etc.