Universal clusters and Efimov physics

Unlike classical systems, quantum few-body systems can be unbound in the presence of short-range attractive forces. Near the critical strength of the forces at which they can become bound (resonant forces), they exhibit universal properties that are independent of the details of the forces. In this lecture, I will explain in detail the universality of systems with resonant short-range forces, in particular the Efimov effect for 3 or more particles. I will also present the universal properties of systems with power-law interaction forces, such as van der Waals forces that are relevant to neutral atoms.