The exploration of ultrafast phenomena is a frontier of condensed matter research, where the interplay of theory, computation, and experiment is unveiling new opportunities for understanding and engineering quantum materials. While pump-probe experimental techniques have progressed rapidly over the last decade, there remains an urgent need to advance ab-initio theory and computational methods to predictively model non-equilibrium phenomena resulting from the electron-phonon interaction (EPI) in condensed matter. This colloquium will illustrate the recent progress in the description of the ultrafast dynamics of electrons and phonons [1], coherent phonons, and phonon decoherence, based on ab-initio simulations of the EPIs. By focusing on a selection of recent examples [1-3], I will highlight the importance of ab-initio ultrafast dynamics simulations to reproduce and understand the results of pump-probe experiments in their full complexity. 

References:
[1] Y. Pan, F. Caruso, Nano Lett. 23, 7463 (2023) 
[2] Y. Pan, P. N. Hildebrand, D. Zahn, M. Zacharias, Y. W. Windsor, R. Ernstorfer F. Caruso, H. Seiler, ACS Nano 19, 11381 (2025) 
[3] C. Emeis, S. Jauernik, S. Dahiya, Y. Pan, P. Hein, M. Bauer, F. Caruso, Phys. Rev. X 15, 021039 (2025)