Efimov Physics and Connections to Nuclear Physics

Physical systems characterized by a shallow two-body bound or virtual state are governed at large distances by a continuous-scale invariance, which is broken to a discrete one when three or more particles come into play. This symmetry induces a universal behavior for different systems, independent of the details of the underlying interaction, rooted in the smallness of the ratio $\mathrm{\ell }\mathrm{/}{a}_B\ll 1$, where the length $a_B$ is associated to the binding energy of the two-body system $E_2={\mathrm{\hslash }}^2\mathrm{/}m{a}_B^2$ and $\mathrm{\ell }$ is the natural length given by the interaction range. Efimov physics refers to this universal behavior, which is often hidden by the on-set of system-specific non-universal effects. In this work we identify universal properties by providing an explicit link of physical systems to their unitary limit, in which $a_B\to \mathrm{\infty }$, and show that nuclear systems belong to this class of universality.