A significant breakthrough in quantum dynamics theory and computational methods has been achieved by a research team led by Dr. Zhang Zhaohan, a recent PhD graduate from the School of Physics and Astronomy at Shanghai Jiao Tong University (SJTU). The work, titled "Time-Dependent Hole States in Multiconfigurational Time-Dependent Hartree-Fock Approaches: A Time-Domain Generalization of Extended Koopmans’ Theorem," has been formally published in the prestigious physics journal Physical Review Letters in January 2026.

This research addresses the longstanding challenge of accurately describing hole-state dynamics in multielectron systems undergoing intense laser-field and ultrafast processes. The team developed a novel theoretical framework that generalizes the Extended Koopmans’ Theorem to the time domain within Multiconfigurational Time-Dependent Hartree-Fock (MCTDHF) theory. This innovation provides a consistent and efficient description of evolving hole states, offering a more precise theoretical and computational tool for studying key ultrafast phenomena such as strong-field ionization, high-harmonic generation, and attosecond transient absorption spectroscopy.

The study was conducted as an international collaboration involving SJTU’s Key Laboratory for Laser Plasmas (Ministry of Education), the Max Planck Institute for Nuclear Physics in Germany, the RIKEN iTHEMS and Center for Computational Science in Japan, and The University of Tokyo. Alumni Zhang Zhaohan (class of 2019), the first author, completed his PhD at SJTU in 2024 and is currently a postdoctoral researcher at the Max Planck Institute for Nuclear Physics. The research received support from the National Natural Science Foundation of China, National Key R&D Program of China, and SJTU’s Key Laboratory for Laser Plasmas.