Laboratoire de Physique Théorique
Toulouse - UMR 5152

Aim and objectives

Following the tradition of the previous successful meetings that have started in 2009, the Theory Days workshop aims at stimulating constructive discussions, collaborations, and knowledge exchange among a selected group of theoreticians. This year, the thirteenth edition will be dedicated to new, high performance, computational methods to describe electronic dynamics.

The development of computational codes for structure and dynamics of electronic systems is experiencing new directions of research in relation to the growing availability of artificial intelligence tools. Machine learning is now applied to numerous computational issues in physics and chemistry, such as for example structure optimization in clusters and molecules. The aim of this year meeting is to address this question in the specific context of dynamical problems, on the basis of existing computational softwares. To restrict the field, we shall focus on fully dynamical approaches allowing us to address dynamical scenarios beyond the domain of linear response. The meeting will thus try to summarize today’s situation in the field, by considering dedicated questions raised by dynamical codes.

A large number of codes rely on Time Dependent Density Functional Theory (TDDFT), which provides a robust and well explored ground for numerous investigations. Various Real Time implementations of TDDFT will thus be presented and discussed. An important issue, for further progress in the field, would be to make systematic code to code comparisons in order to better analyze code capabilities and contents. This nevertheless requires to agree on well defined test cases and parameters, which represents a joined effort and requires some computation time. This is the second goal of this year meeting to gather a few experts on real time implementations of TDDFT with the aim to meet again next year (2022) for a comparison of code performances and results. One slot will be devoted to an open discussion to agree on a few illustrative test cases (systems, observables) to be computed. To optimize the discussion, the participants will be asked to think in advance about the possible test cases that might be addressed in their codes so that a consensus can be hopefully reached during this discussion.

We plan to gather people from various groups working in this domain, mostly in western Europe. The workshop is intended to be a working forum, thus rather informal. The format will consist in a series of long detailed talks, typically 1 hour (40 mn talk + 10 mn for questions) focusing in particular on ongoing problems and open issues. We thus urge participants to prepare their talks in this spirit. Ultimately a most efficient organization would consist in having a limited number of talks per representative group in order to avoid doublings.

Scientific program

Exceptionally, and due to the special circumstances of the Covid-19 pandemic, especially the uncertainties concerning the evolution of the sanitary situation, this year’s venue (workshop) will be partly organized through visio conferencing for speakers outside Toulouse. For those who are in Toulouse, the meeting rooms are specified below. The meeting will take Wednesday November 24th 2pm to Friday November 26th 1pm.

Wed Nov 24th 2021

Meeting room : salle 20, RdC, Bat. 3R1

• 14:00-14:50 : P.-G. Reinhard (Institute for Theoretical Physics, University Erlangen, Germany), "Quantum Dissipative Dynamics code (QDD) - example short XUV pulses"

• 15:00-15:50 : N. Tancogne-Dejean (MPSD, Hamburg, Germany), "Multisystem implementation in Octopus : different shades of light-matter interactions"

• 16:00-16:50 : Mario Barbatti (Aix-Marseille University, Marseille, France), "Nonadiabatic dynamics in the long timescale : the next challenge in computational photochemistry"

Thu Nov 25th 2021

Meeting room : salle de séminaires FeRMI, 3ème étage, Bat. 3R1

• 09:00-09:50 : N. Renon (Regional Computing Center CalMiP, Toulouse, France), "Processor Architecture Evolution and Roofline model ; Some feedback on GPUs"

* 10:00-10:50 : K. Yabana (University of Tsukuba, Japan), "Real-time TDDFT coupled with Maxwell equations for light propagation through thin films"

• 11:00-11:50 : D. Dundas (School of Mathematics and Physics, Queen’s University of Belfast, UK), "EDAMAME : Ehrenfest DynAMics on Adaptive MEshes"

• 13:00-14:00 : discussion

• 14:00-14:50 : E. Artacho (CIC NanoGUNE, San Sebastian, Spain), "Real time TDDFT with moving atomic orbitals as basis sets and the SIESTA implementation"

• 15:00-15:50 : K. Varga (VanderBilt university, Nashville, TN, USA), "Modeling the interaction of electromagnetic fields and nanostructures using the time-dependent orbital free density functional theory"

• 16:00-16:50 : I. Tavernelli (IBM, Zürich, Switzerland), tba

Fri Nov 26th 2021

Meeting room : salle 20, RdC, Bat. 3R1

• 09:00-09:50 : A. de la Lande (Institut de Chimie Physique, Orsay, France), "High performance real-time time dependent auxiliary DFT for application to radiation chemistry problems"

• 10:00-10:50 : M. Rapacioli (Laboratoire de Physique et Chimie Quantiques, Toulouse, France), "deMonNano : Density Functional based Tight Binding for adiabatic and nonadiabatic dynamics"

• 11:00-11:50 : M. Vacher (University of Nantes, France), "Coupled electron-nuclear dynamics and insights from machine learning"

• 12:00-12:50 : R. Vuilleumier (Ecole Normale Supérieure, Paris, France), Electron dynamics in the slow nuclei limit : what can we learn from perturbation theory

• 12:50-13:00 : Concluding remarks