1. Electronic structure and properties of matter

A few preliminary methodological remarks are in order, particularly concerning the notion of model, central in physics, and the articulation between theory, experiment and simulation. Even if the constitutive equations of matter are known a priori, the systems studied by condensed matter physics, such as a solid surface, are too complicated to be able to deduce their behavior ab initio from atomic-scale considerations without the aid of more or less highly simplifying hypotheses. So physicists develop, manipulate and refine models, which are simplified representations of the complicated objects they describe. A model is a snapshot of current knowledge, and is therefore intrinsically subject to change. Since Popper, we know that science progresses by disproving its models, discovering their flaws and producing better ones. A model is therefore constantly tested, attacked and questioned,...