Fonctionnelles de la densité: des systèmes atomiques aux systèmes nucléaires

3 juin 2019, 10:30 → 5 juin 2019, 15:00 Europe/Paris

Amphithéâtre Dirac (IPN Lyon)

Density functionals: from atomic to nuclear systems.

This event will bring together theorists working in fields ranging from quantum chemistry to nuclear physics, including cold atomic gas, nuclear astrophysics, etc.... The common red-line of this event is the nuclear many-body theory which has a very wide domain of application. We will review progresses in very different fields as shown in the program. The aim of this workshop is to foster cross-fertilization among these fields, identifying common frameworks as well as possible conceptual differences.

As participants will have a variety of different backgrounds, we will ask speakers to give presentations as pedagogical as possible. We also invite young researchers to apply for the short talks (20min).

The registration closure is May, 19th.

This meeting is supported by the GdR RESANET (GT3), the Labex LIO, the Centre Blaise Pascal (CBP), the Fédération Lyonnaise de Modélisation et Sciences Numériques (FLMSN) and the noeud Rhône Alpin du CECAM (CECAM-FR-RA) and the laboratories ILM and IPNL.

Local Organization Committee: K. Bennaceur (IPNL), T. Albaret (ILM), L. Joly (ILM), J. Margueron (IPNL).

Scientific Committee: T. Albaret (ILM), K. Bennaceur (IPNL), Jean-Paul Ebran (CEA/DAM), Razvan Caracas (ENS Lyon), Henry Chermette (ISA), Thomas Duguet (IRFU/SPhN), Ubirajara van Kolck (IPN Orsay), Thomas Niehaus (ILM), Franck Rabilloud (ILM).

lun. 3 juin

10:30 → 12:05 Morning 03/06

Président de session: guy chanfray (IPN Lyon)

10:30 Welcome and coffee

11:00 Introduction

Mme Anne Ealet, director of IPNL
M. Philippe Dugourd, director of ILM
M. Jérôme Margueron, GdR RESANET
M. Karim Bennaceur, for the organizing committee

11:15 Energy density functional methods for low-energy nuclear structure and reactions (tentative title)

Orateur: Michael Bender (IPN Lyon)

12:30 → 13:30 Lunch

14:00 → 17:20 Afternoon 03/06

Président de session: henry chermette (ISA)

14:00 An introduction to density functional theory

This will be an introduction to density-functional theory, starting from the founding Hohenberg-Kohn and Kohn-Sham theorems to more advanced problems. In particular, we will discuss the history of the development of exchange-correlation functionals, and the availability of such functionals for the study of different physical systems.

Orateur: Miguel Marques (Martin-Luther University of Halle-Wittenberg)

14:50 Ensemble density-functional theory for excited states

I will discuss the basics and recent developments in the field of (time-independent) ensemble density-functional theory for neutral and charged electronic excited states.

Orateur: M. Emmanuel Fromager (University of Strasbourg)

15:40 Coffee

16:10 Dynamics of electrons and nuclei in molecules: Beyond the Born-Oppenheimer approximation

Excited-state dynamics is at the heart of Photophysics and Photochemistry. Nonadiabatic transitions are induced by the strong coupling between electronic dynamics and the ultrafast motion of the nuclei, and are observed in phenomena such as photosynthesis, photovoltaics, and exciton transport in π-conjugated complexes. An essential part of the research efforts in these fields is directed towards developing theoretical and computational approaches to describe conformational changes, energy dissipation, or quantum decoherence, i.e., the signature aspects of excited-state processes. In this context, among the most successful frameworks for molecular dynamics simulations of excited-state processes stand trajectory-based quantum-classical methods, as they give access to the study of complex molecular systems. Trajectory-based approaches combine a classical description of nuclear dynamics with a quantum-mechanical description of electronic dynamics. However, the approximations underlying quantum-classical methods are sometimes severe, and are at the origin of controversies as well as of continuous developments.
In this talk I will present a recently-developed trajectory-based approach to nonadiabatic dynamics [1,2]. The actual numerical scheme has been derived from the exact factorization of the electron-nuclear wavefunction [3], a new framework proposed to investigate, interpret and approximate the coupled dynamics of electrons and nuclei beyond the Born-Oppenheimer approximation. The exact factorization provides a new perspective to analyze nonadiabatic processes: (i) it proposes an alternative [4] to the standard Born-Oppenheimer framework, that pictures excited-state processes in terms of wavepackets moving on and transferring between static potential energy surfaces; (ii) it suggests new interpretations [5] of molecular geometric-phase effects, related to conical intersections; (iii) it provides guidelines for developing simulation algorithms in different [6] nonadiabatic regimes. These points will be discussed during the talk and illustrated on low-dimensional models and molecular systems.

[1] S. K. Min, F. Agostini, I. Tavernelli, E. K. U. Gross, J. Phys. Chem. Lett. 2017, 8, 3048-3055.
[2] S. K. Min, F. Agostini, E. K. U. Gross, Phys. Rev. Lett. 2015, 115, 073001.
[3] A. Abedi, N. T. Maitra, E. K. U. Gross, Phys. Rev. Lett. 2010, 105, 123002.
[4] A. Abedi, F. Agostini, Y. Suzuki, E. K. U. Gross, Phys. Rev. Lett. 2013, 110, 263001.
[5] B. F. E. Curchod, F. Agostini, J. Phys. Chem. Lett. 2017, 8, 831-837.
[6] A. Scherrer, F. Agostini, D. Sebastiani, E. K. U. Gross, R. Vuilleumier, Phys. Rev. X 2017, 7, 031035.

Orateur: Federica Agostini (Laboratoire de Chimie Physique, Université Paris-Sud)

17:00 Density functional, from nuclei to neutron stars

I will present a meta-modeling of the equation of state for the description of nuclear matter, and its application to neutron stars, where the density can reach several times the saturation density of atomic nuclei (the average density of nuclei). This equation of state is based on the extrapolation of our knowledge in nuclear physics around saturation density, towards high density, encoded in terms of a Taylor expansion of the potential energy. The unknown high order parameters of this expansion have a strong impact at high density, and can therefore be constrained by observations of neutron stars. I will illustrate the case of thermal emission from neutron stars and their constrain on the empirical parameter $K_{sym}$ and $Q_{sat}$.

Orateur: Nicolas Baillot d'Etivaux (IPN Lyon)

mar. 4 juin

09:00 → 12:20 Morning 04/06

Président de session: Tristan Albaret (ILM, Université Lyon 1)

09:00 Time-dependent DFT: Foundations, Fruition and Failures

I attempt to review the present state of time-dependent density functional theory (TDDFT) [1,2] applied to electronic systems. After a brief view at the mathematical foundations, I discuss the numerical aspects of the method and provide some illustrative examples of its application. I will also show some of the difficulties that plague TDDFT and how they start to be addressed.

[1] Time-dependent Density-Functional Theory, Carsten A. Ullrich, Oxford University Press,2012.
[2] Time-dependent Density-Functional Theory, MAL Marques and EKU Gross, Annu. Rev. Phys. Chem. 55, 427, (2004)

Orateur: Thomas NIEHAUS (Institut Lumière Matière, Lyon)

09:50 What can we learn from ultracold atoms about dilute neutron matter?

Orateur: Michael Urban (IPN Orsay)

10:40 Coffee

11:10 Applications of EDF for astrophysics

Orateur: Francesca Gulminelli (LPC/Ensicaen)

12:00 General predictions for the neutron star crustal moment of inertia

The neutron star crustal EoS and transition point properties are computed within a unified meta-modeling approach. A Bayesian approach is employed including two types of filters: bulk nuclear properties are controlled from low density effective field theory (EFT) predictions as well as the present knowledge from nuclear experiments, while the surface energy is adjusted on experimental nuclear masses. Considering these constraints, a quantitative prediction of crustal properties can be reached with controlled confidence intervals and increased precision with respect to previous calculations: $\approx 11\%$ dispersion on the crustal width and $\approx 27\%$ dispersion on the fractional moment of inertia. The crust moment of inertia is also evaluated as a function of the neutron star mass, and predictions for mass and radii are given for different pulsars. The possible crustal origin of Vela pulsar glitches is discussed within the present estimations of crustal entrainment, disfavoring a large entrainment phenomenon if the Vela mass is above $1.4M_\odot$. Further refinement of the present predictions requires a better estimation of the high order isovector empirical parameters, e.g. $K_{sym}$ and $Q_{sym}$, and a better control of the surface properties of extremely neutron rich nuclei.

Orateur: Thomas Carreau (LPC Caen)

12:30 → 13:30 Lunch

14:30 → 17:00 Afternoon 04/06

Président de session: Prof. Caracas Razvan (ENS Lyon)

14:30 TBA

Orateur: Andreas Savin (Laboratoire de Chimie Theorique, CNRS at Sorbonne Universite)

15:20 TBA

Orateur: Swagata Mallik Mallik (LPC Caen)

Application of meta-modeling of the EoS in nuclear multifragmentation reactions at intermediate energies

15:40 Coffee

16:10 Breaking and restoring symmetries in ab initio many-body formalisms

Orateur: Thomas Duguet (CEA/Saclay/SPhN)

20:00 → 23:00 Conference diner

mer. 5 juin

09:00 → 12:10 Morning 05/06

Président de session: Jacques MEYER (Institut de Physique Nucléaire de Lyon)

09:00 Modeling reactivity at the solid-liquid interface

To describe reactions occurring at the solid/water interface is currently one of the major challenges in modeling in Heterogeneous Catalysis. It requires a proper depiction of the water solvent together with an adequate description of the surface state. Several approaches are available nowadays in the literature, from continuum models to a full explicit description of the liquid water [1]. We have recently shown that continuum models are key to a proper description of reactions occurring at the electrochemical interface on the formic acid oxidation into CO2 [2]. They also open the door to a proper inclusion of the effect of co-adsorbed anions in thermal heterogeneous catalysis [3]. In both cases, charges are involved and the electrostatic contribution in the major one. When H-bonding between the liquid water and the reactant or intermediate is crucial, continuum models are not sufficient and an explicit inclusion of water molecule is a necessity. As a first step, micro-solvation can be an effective approach that allowed us to interpret solvent effect in the conversion of levulinic acid into γ-valerolactone [4]. Moving to a full description of reactivity the water/metal interface is still beyond a full complete DFT approach provided the minimal size of the periodic cell that is necessary and the minimal sampling required. A combined QM/MM approach could be a promising strategy [5], but necessitates a new generation of metal/water force field [6]. Nevertheless, being less demanding, inspecting transformations occurring at oxide/water interface is now reachable, as illustrated by our recent work on the stability of γ-alumina in water [7].
References:
[1] M. Saleheen, A. Heyden, ACS Catal. 8, (2018), pp. 2188-2194
[2] S. N. Steinmann, C. Michel, R. Schwiedernoch, J.-S. Filhol, P. Sautet, Chemphyschem, 16 (2015), pp. 2307-2311
[3] P. Wang, S. N. Steinmann, G. Fu, C. Michel, and P. Sautet, ACS Catalysis, 7, (2017), pp. 1955–1959
[4] C. Michel, J. Zaffran, A. M. Ruppert, J. Matras-Michalska, M. Jedrzejczyk, J. Grams, P. Sautet, Chem. Comm. 50 (2014), pp. 12450–12453
[5] S. N. Steinmann, P. Sautet, and C. Michel, Phys Chem Cheml Phys, 18, (2016), pp. 31850–31861
[6] S.N. Steinmann, R. Ferreira De Morais, A. W. Götz, P. Fleurat-Lessard, M. Iannuzzi, P. Sautet, C. Michel, J Comp Theo Chem, submitted, (2018)
[7] R. Réocreux, “Biomass derivatives in heterogeneous catalysis: adsorption, reactivity and support from first principles”, PhD thesis, (2017)

Orateur: Carine Michel (Laboratoire de Chimie, Ecole Normale Supérieure de Lyon)

09:50 Selected interdisciplinary aspects of static and time-dependent nuclear DFT

Orateur: Denis LACROIX (Institut de Physique Nucléaire)

10:40 Coffee

11:10 Summary talk: On DFT and EDF in finite fermion systems

Examples in various systems. Statics and dynamics.

Orateur: Eric Suraud (Université Paul Sabatier)

12:30 → 13:30 Lunch