Heteronuclear Efimov resonances in ultracold quantum gases

The Efimov scenario is a universal three-body effect addressing many areas of modern quantum physics.It plays an important role in the transition between few- and many-body physics and has enabled important breakthroughs in the understanding of the universal few-body theory.We review the basic concepts of the Efimov scenario with specific emphasis on the similarities and differences between homonuclear and heteronuclear systems.In the latter scenario,the existence of a second,independently tunable interaction parameter enables novel few-body phenomena that are universal and have no counterexamples in the homonuclear case.We discuss recent experimental approaches using ultracold atomic gases with magnetically tunable interactions and elucidate the role of short-range interactions in the emergence of universal and non-universal behavior.