Nature is certainly not invariant under changes of scale. Phenomena and laws are characterized by parameters that determine their dimensions. However, while the complexity of some many-body systems may stem from a profusion of distinct scales, rich structures exist even when there is no more than one essential scale associated with *discrete* scale invariance. I will discuss how intrinsically quantum-mechanical structures with unique properties, sometimes labeled "Efimov physics", emerge in nuclear and some closely related atomic systems from a contact three-body force.
Ubirajara (Bira) van Kolck is a Directeur de Recherche at France's Centre National de la Recherche Scientifique and a Professor of Physics at the University of Arizona. After receiving his Ph.D. in 1993 from the University of Texas at Austin under the supervision of S. Weinberg, he held postdoctoral appointments at the University of Washington and Caltech. He has been a RHIC Physics Fellow, a DOE Outstanding Junior Investigator, and a Sloan Fellow. He is a Fellow of the American Physical Society and received the Prix Paul Langevin of the Societe Francaise de Physique in 2015. His interests center on effective field theories and the emergence of nuclear physics from the Standard Model and its extensions.