 Two years later, he joined Claude Bloch's theorists' working group, to which he belonged for the rest of his career.In 1967 he received from the University of Paris-Sud in Orsay his doctoral degree in physics with thesis "Étude d'un modèle à une dimension pour un système de fermions en interaction".Gaudin's research deals with, among other topics, the quantum-mechanical description of many-body systems, in particular, spin systems.