BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Memento EPFL// BEGIN:VEVENT SUMMARY:Fingerprints of electron correlation in materials: understanding a nd predictions from electronic structure theory DTSTART:20160509T131500 DTEND:20160509T141500 DTSTAMP:20260916T081105Z UID:ef1ceebdd3d934987ea39521cee819e187b6ec907911f50ed23bd1cd CATEGORIES:Conferences - Seminars DESCRIPTION:Dr. Lucia Reining\, Laboratoire des solides irradiés\, École Polytechnique France\nElectronic excitations determine the characteristic s of materials all over science and technology\, from photochemistry to ra diation defects\, from synchrotron experiments to cancer research. Theory and numerical modelling are valuable tools for the understanding and predi ction of many of the important phenomena. During the last decades the fiel d has evolved rapidly\, but there are still many challenges. For example\, some structures in the excitation spectra of interacting electrons\, call ed quasiparticle peaks\, can be directly related to excitations of indepen dent electrons. Others\, instead\, such as satellites in the photoemission spectra of solids\, cannot be understood in such a simple way. They are p ure consequences of interaction and correlation\, and they cannot be inter preted in a pure bandstructure picture. First principles calculations are in general very efficient in describing bandstructure\, especially methods based on many-body perturbation theory such as the so-called GW approxima tion [1]. However\, they  often have difficulties to describe quantitativ ely\, or even qualitatively\, everything that goes beyond.\nIn this talk w e will see what state-of-the art first principles calculations can today c ontribute to our understanding\, focussing on the main ideas of the underl ying theories\, their conceptual and technical limitations\, and useful co mparisons with\, and interpretation of\, experiment.\nWe will show ways to go beyond currently used approximations\, and we will discuss fingerprint s of correlation in photoemission\, inelastic x-ray scattering and optical spectra\, making close connections between theory and experiment. Systems used for illustration will include models\, simple metals and semiconduct ors\, carbon nanostructures and transition metal oxides [2].\nThe results have been obtained in collaboration with many colleagues in the Theoretica l Spectroscopy Group of the  Laboratoire des Solides Irradiés and in the European Theoretical Spectroscopy Facility.\n[1] L. Hedin\, Phys. Rev. 13 9\, A796 (1965).\n[2] see e.g. M. Guzzo et al.\, Phys. Rev. Lett. 107\, 16 6401 (2011) and Phys. Rev.B 89\, 085425 (2014)\; M. Gatti\, G. Panaccione\ , and L. Reining\, Phys. Rev. Lett. 114\, 116402 (2015)\; J. Zhou et al.\,   J. Chem. Phys. 143\,  184109 (2015)\; P. Cudazzo et al.\, Phys. Rev. L ett. 116\, 066803 (2016).\nBio: Lucia Reining is senior researcher of the Centre National de la Recherche Scientifique (CNRS) at the École Polytech nique in Palaiseau\, France. She obtained her master degree in Aachen\, Ge rmany\, and her PhD in Rome\, Italy. She did her postdoctoral research at the Centre Européen de Calcul Atomique et Moléculaire (CECAM) in Orsay\, France\, and entered the CNRS at the École Polytechnique in Palaiseau in 1992\, where she is today Directrice de Recherche de 1ère classe\, coord inator of  the Theoretical Spectroscopy Group.\nHer work covers many-body perturbation theory and time-dependent density functional theory with a f ocus on development of new approaches and combination of methods. As a fou nding member of the European Theoretical Spectroscopy Facility\, she moreo ver promotes collaboration between theory and experiment\, more specifical ly concerning spectroscopies such as photoemission\, electron energy loss or inelastic x-ray scattering experiments.\nLucia Reining holds an ERC adv anced grant aiming at the design of a non-perturbative method for the calc ulation of spectral functions\, and she is a recipient of the CNRS Silver Medal and a Fellow of the American Physical Society. LOCATION:MXF 1 https://plan.epfl.ch/?room==MXF%201 STATUS:CONFIRMED END:VEVENT END:VCALENDAR