Séminaire - 19/12/2022 - Sebastian Volz - Temporal Coherence in Heat Conduction
Invitation : Marc Bescond (Département EMONA, Equipe NQS).
Diffusion : IM2NP, CINaM, Irphe, LP3 (via N. Sannier), Madirel (via R. Denoyel), PIIM (via T. Angot), CPT (T. Martin), Fédération de Chimie (via S. Viel), CP2M
SEMINAIRE Lundi 19 Décembre 2022 à 14h00
Salle des séminaires de l'Im2np, campus de Saint-Jérôme, 1er étage Bâtiment Poincaré
Le séminaire sera suivi à 15h d'un café/buffet afin d'échanger avec les personnes présentes.
Sébastien Volz*
LIMMS/CNRS-IIS(UMI2820), Institute of Industrial Science, The University of Tokyo
4-6-1 Komaba, Meguro-ku, Tokyo 153-8505 JAPAN
Temporal Coherence in Heat Conduction
Coherence of thermal excitations is a long-standing and general problem in physics. The conventional theory of the phonon gas model indeed does not include coherence and its impact on thermal transport.
We propose a general heat conduction formalism based on theoretical arguments and direct atomic simulations, which bridges conventional phonon gas model and the wave picture of thermal phonons.
By naturally introducing wavepackets in the fundamental heat flux expression [1], we derive an original thermal conductivity formula where coherence times and life-times appear [2]. We apply the theory to a complex crystal where interatomic potentials are optimized by a Machine Learning procedure. The simulation reveals an intrinsic and a -previously investigated- mutual coherence appearing in two different temperature ranges.
[1] Zhongwei Zhang, Yangyu Guo, Marc Bescond, Jie Chen, Masahiro Nomura, and Sebastian Volz, Generalized decay law for particlelike and wavelike thermal phonons, Physical Review B 103(18):184307.
[2] Z. Zhang, Y. Guo, M. Bescond, J. Chen, M. Nomura and S. Volz, Heat conduction theory including phonon coherence. Physical Review Letters, 128 (1), 015901, (2022).
*Sebastian Volz, CNRS Professor
LIMMS, Director
