## Understanding and predicting the coupled and coherent electron-phonon dynamics of quantum states

Ultra-short laser pulses can be used to initiate, manipulate, and control coherent electron dynamics. A wealth of physical processes and novel quantum phenomena can be explored, such as topological states, Floquet physics, coherent exciton Bose-Einstein condensation, and spin precession driven by coherent magnons in quantum materials. For example, in biological systems, charge migration can be enhanced by coherent dynamics of phonons and electrons. This phenomenon, already seen in photosynthesis, is of central importance for designing efficient organic opto-electronic devices. All these involve energetically excited states that gradually lose coherence via interaction with the environment. This constitutes a major limiting factor for realizing quantum-computing material designs, stabilizing light-driven topological states (Floquet topology), or allowing exciton condensates in condensed matter. The TIMES network will face the challenge of understanding and predicting the coupled and coherent electron-phonon dynamics of quantum states. The developed theoretical approaches, in collaboration with experimental partners will push the boundaries of the current simulations of out-of-equilibrium phenomena.

#### Project: Spin-waves in magnetic 2D materials

Ab initio simulations of magnons in 2D materials with distinct magnetic order like ferromagnets, antiferromagnets or helicoidal magnetic order. Study of magnon dynamics and magnon-phonon interaction. This project will explores the rich phenomenology of opto-magnetic properties on 2D magnetic materials.

##### See related publications on 2D magnetism!

**Broken-symmetry magnetic phases in two-dimensional triangulene crysta****ls**

G. Catarina, J. C. G. Henriques, A. Molina-Sánchez, A. T. Costa, J. Fernández-Rossier

Phys. Rev. Research 5, 043226 (2023)

**Magneto-optical response of chromium trihalide monolayers: chemical trends**

A. Molina-Sánchez, G. Catarina, D. Sangalli, J. Fernández-Rossier

J. Mater. Chem. C 8, 8856 (2020)

PI: **Alejandro Molina-Sánchez**

University of Valencia (Spain)

#### Project: Fast decoherence processes in quantum materials

The project focus on developing TDDFT-based methods to study fast decoherence processes in quantum materials, using the Octopus code. The developed methods will be useful to describe ultrafast time-resolved spectroscopies in quantum materials for the study of Floquet topological phases and high-harmonic generation of Weyl semimetals.

##### See related publications on Coherence, TDDFT and Floquet Physics!

**Floquet band engineering in action**

H. Hübener, U. De Giovannini, S. A. Sato, A. Rubio

Science bulletin 68 (8), 751-752 (2023)

**Floquet engineering the band structure of materials with optimal control theory**

A. Castro, U. De Giovannini, S. A. Sato, H. Hübener, A. Rubio

Physical Review Research 4 (3), 033213 (2022)

PI: **Umberto di Giovannini**

University of Palermo (Italy)