Frontiers in many-body excited-state dynamics from first principles
Location: CECAM-HQ-EPFL, Lausanne, Switzerland
Organisers
Extensive research is dedicated to studying excited-state phenomena when materials are exposed to light. This research provides valuable insights into the relationship between material's structure and functionality for a range of applications, from energy conversion to quantum information storage. Recent advances in ultrafast pump-probe spectroscopy have led to the discovery of emergent transient quantum phenomena and new capabilities to track excited-state dynamics at unprecedented temporal and spatial resolution. These spectroscopic measurements encode complicated signatures of lattice, electronic and multiparticle dynamics, occurring on different time and energy scales and in different regions of momentum space, which are beyond the capabilities of standard first principles theories to unravel. Consequently, in parallel with advances in spectroscopy, there has been a concerted effort to develop new predictive first principles theories and computational tools that can rigorously account for time-dependent many-body correlations and their coupling with the lattice.
Green’s function approaches based on many-body perturbation theory represent the state-of-the-art for calculating excited-state spectra in the low-field linear response regime. Recent advances in the field include the development of Green’s function based nonequilibrium and perturbative approaches [1,2], allowing for accurate simulations of processes such as transient absorption, time-resolved angle-resolved photoemission (TR-ARPES), two-photon absorption spectra, and nonlinear spectroscopies [3-5] and supply insights into the interactions of a zoo of quasiparticles, like electrons, excitons, phonons, polarons, and polaritons [6-9].
Accurate theoretical treatment of multiple interacting particles and nonequilbiurm time-dependent behavior involves necessarily an exponentially greater computational cost and requires parallel development of innovative data-driven approaches to improve computational tractability. Practical applications became accessible owing to new theory and code developments, with a growing number of applications to explore nonadiabatic phenomena. New numerical techniques, such as ab-initio data-driven methods and quantum embedding theories [10, 11] , mark a new era in which many-body predictive approaches can be merged with data analysis, opening the door to accurate predictions of quantum state evolution in realistic materials.
Our workshop will focus on new advances in the development and application of first-principles non-equilibrium many-body dynamics in emerging materials for quantum science. While the workshop is primarily aimed at discussing the theoretical aspects, we are aiming to cover a rich diversity of materials, methods and applications, in connection with recent experimental advances. Through the presented research and discussions, we hope to reach an updated view of state-of-the-art approaches to first-principles computations of excited-state dynamics in quantum materials, as well as to share challenges and discuss new and emergent directions in the field.
References
Sivan Refaely-Abramson (Weizmann Institute of Science) - Organiser
United Kingdom
Marina Filip (University of Oxford) - Organiser
United States
Diana Qiu (Yale University) - Organiser