Les Houches School of PhysicsSince 1951

M. Kardar, G. Parisi and Y-C. Zhang proposed in 1986 an equation describing the scale invariance of various phenomena. This field has experienced a second life in recent years with the identification of universal properties highlighted in very different models, both at the theoretical (spin chains, lattice gases) and experimental (cold atoms, exciton-polaritons) levels. Our goal is to provide a broad and accessible overview of these advances, together with the most recent results on these topics.