Tackling nonlocal electronic correlations with the dynamical vertex approximation

The dynamical mean-field theory (DMFT), in combination with density functional theory (DFT), has been developed into a powerful computational tool for materials with strong electronic correlations. Nevertheless, DMFT is based on the solution of a quantum impurity model and can account only for local electronic correlations. Diagrammatic extensions of DMFT such as the dynamical vertex approximation (DΓA) are attempting to include nonlocal correlations and long-range Coulomb interactions.

PhD: Ab initio Calculation of the Optical Properties of Metal Clusters

We are looking for a candidate for a fully funded PhD position on the "Ab initio Simulation of Optical Properties of Metal Clusters" based mostly on TDDFT calculations. A description of the project, which will be carried out at the CINAM in Marseille, can be found here.


Interference effects in one-dimensional moiré crystals

This work [1] investigates interference effects in finite sections of 1D moiré crystals using the Landauer-Büttiker formalism within the tight-binding approximation. We explain interlayer transport in double-wall carbon nanotubes and demonstrate that wave function interference is visible at the mesoscale: in the strong coupling regime, as a periodic modulation of quantum conductance and emergent localized states; in the localized-insulating regime, as a suppression of interlayer transport, and oscillations of the density of states.

New approximation to the exchange correlation potential from connector theory approach

In the Kohn-Sham formulation of density functional theory (DFT) [1], the ground-state density of interacting electrons can be obtained from a fictitious system of independent particles in an effective potential. Although DFT is in principle exact the effective potential contains an unknown quantity called the exchange-correlation (xc) potential. In this talk we propose a new approximation to the xc potential using a general approach called "Connector Theory" (COT) [2].

Theoretical Spectroscopy Lectures

Electronic excitations are probed by experimental techniques such as optical absorption, EELS and photo-emission (direct or inverse). From the theory point of view, excitations and excited state properties are out of the reach of density-functional theory (DFT), which is a ground-state theory. In the last twenty years other ab-initio theories and frameworks, which are able to describe electronic excitations and spectroscopy, have become more and more used:

25th ETSF Workshop on Electronic Excitations

The ETSF workshop series provides a forum for excited states and spectroscopy in condensed-matter physics, chemistry, nanoscience, materials science, and molecular physics attracting theoreticians, code developers, and experimentalists alike. The 2022 edition of the workshop will focus on fundamental challenges for theoretical spectroscopy posed by cutting-edge present and future technologies, thereby promoting a fruitful exchange between academia and industry.

Postdoctoral position on the modeling of silicon/germanium spin qubits at CEA/IRIG, Grenoble, France

A post-doctoral position is open at the Interdisciplinary Research Institute of Grenoble (IRIG) of the CEA Grenoble (France) on the theory and modeling of silicon/germanium spin quantum bits (qubits). The selected candidate is expected to start in July 2022 (or later), for up to three years.

Ab initio approach to exciton dynamics

In this talk I present a fully ab initio approach to model the generation of non-equilibrium coherent
excitonic states with ultra-short laser pulses. The modelling is achieved via the real-time propagation
of the density matrix projected in the Kohn-Sham basis set, within the time{dependent Hartree plus
Screened EXchange (TD-HSEX) approaximation [1].
I show how the generated density matrix can be used to model transient spectroscopy signals

Breakdown of LO-TO polar splitting in 1D materials and its application to nanowire and nanotubes

Accurate models and simulations of the vibrational properties of 1D materials are crucial for

the analysis and prediction of transport and spectroscopic properties. In the long-wavelength

limit, longitudinal polar-optical phonons (those probed by IR and Raman spectroscopies) are

known to undergo a frequency shift which depends strongly on dimensionality. In 3D, this leads

to a roughly constant separation between the optical modes across the Brillouin zone, termed

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