Fermi liquids and quasiparticles

The lecture on May 26 was devoted to some essential aspects of Fermi's liquid theory. Particular emphasis was placed on describing the excitations of the system in terms of "quasiparticles", presenting the essential characteristics of these excitations: dispersion (effective mass), lifetime and spectral weight. We have shown how advances in angle-resolved photoemission spectroscopy (ARPES) now enable these excitations to be imaged directly, as illustrated by the seminar given by Véronique Brouet (LPS-CNRS and Université d'Orsay) on June 2 on the theme "New iron superconductors seen by angle-resolved photoemission". Recent developments in the physics of two-dimensional Fermi liquids in the context of liquid Helium-3 were presented by Henri Godfrin (Institut Néel, CNRS, Grenoble) in a seminar on May 26.