In recent years, ultrafast pump-probe spectroscopy has provided insightful information about nonequilibrium dynamics of excitations in materials. In a typical experiment of time-resolved x-ray absorption spectroscopy, the systems are excited by a femtosecond laser pulse (pump pulse) followed by an x-ray (probe pulse) after a time delay to measure the absorption spectra of the photoexcited systems. We present a theory for nonequilibrium x-ray absorption spectroscopy in one-dimensional strongly correlated systems. The core hole created by x-ray is modeled as an additional effective potential of the core hole site which changes the spectrum qualitatively. In equilibrium, the spectrum reveals the charge gap at half-filling and the metal-insulator transition in the presence of the core hole effect. Furthermore, a pump-probe scheme is introduced to drive the system out of equilibrium before the x-ray probe. The effects of the pump pulse with varying frequencies, shapes and fluences are discussed for the dynamics of strongly correlated systems in and out of resonance. The spectrum indicates that the driven insulating state has a metallic droplet around the core hole. The rich structures of the nonequilibrium x-ray absorption spectrum give more insight into the dynamics of electronic structures.
Ultrafast Magneto-Pressure Spectroscopy and Control of Correlated Phases in a Trilayer Nickelate
Ames National Laboratory, U.S. Department of Energy（艾姆斯国家实验室）；Department of Physics and Astronomy, Iowa State University（爱荷华州立大学物理与天文学系）；Materials Science Division, Argonne National Laboratory（阿贡国家实验室材料科学部）；School of Physics, Southeast University（东南大学物理学院）；Department of Physics, University of Alabama at Birmingham（阿拉巴马大学伯明翰分校物理系）
Ultrafast electron crystallography reveals the atomic pathway of a light-driven correlated insulator-to-metal transition
Stockholm University（斯德哥尔摩大学）；Uppsala University（乌普萨拉大学）；Technion–Israel Institute of Technology（以色列理工学院）；KTH Royal Institute of Technology（瑞典皇家理工学院）；Australian National University（澳大利亚国立大学）
Ultrafast giant enhancement of second harmonic generation in a strongly correlated cobaltite
Beijing Academy of Quantum Information Sciences（北京量子信息科学研究院）；Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences（中国科学院物理研究所凝聚态物理北京实验室）；University of Chinese Academy of Sciences（中国科学院大学）；International Center for Quantum Materials, School of Physics, Peking University（北京大学物理学院量子材料科学中心）；School of Electronic and Information Engineering, Beihang University（北京航空航天大学电子信息工程学院）；School of Physics and Center of Quantum Materials and Devices, Chongqing University（重庆大学物理学院量子材料与器件中心）；School of Materials Science and Engineering, Nankai University（南开大学材料科学与工程学院）
Theory of Ultrafast Spin--Charge Quantum Dynamics in Strongly Correlated Systems Controlled by Femtosecond Photoexcitation: an Application to Insulating Antiferromagnetic Manganites
High Harmonic Tracking of Ultrafast Electron Dynamics across the Mott to Charge Density Wave Phase Transition
Wrocław University of Science and Technology（弗罗茨瓦夫科技大学）；ICFO - Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology（ICFO-光子科学研究所，巴塞罗那科学技术研究院）；Universidad de Valencia-CSIC（瓦伦西亚大学-西班牙国家科学研究委员会）；ICREA（加泰罗尼亚高级研究学院）；DIPC - Donostia International Physics Center（圣塞巴斯蒂安国际物理中心）；IKERBASQUE, Basque Foundation for Science（伊克尔巴斯基克，巴斯克科学基金会）；ISQI - Institute of Spintronics and Quantum Information, Adam Mickiewicz University（自旋电子学与量子信息研究所，亚当·密茨凯维奇大学）
Energy density driven ultrafast electronic excitations in a cuprate superconductor
Università Cattolica del Sacro Cuore（天主教神圣之心大学）；ILAMP (Interdisciplinary Laboratories for Advanced Materials Physics)（先进材料物理跨学科实验室）；KU Leuven（荷语鲁汶大学）；Elettra - Sincrotrone Trieste S.C.p.A.（的里雅斯特电子同步加速器）；Brookhaven National Laboratory（布鲁海文国家实验室）；CNR-INO (National Institute of Optics)（意大利国家光学研究所）
