Abstract
We study a system of spinless fermions in two dimensions with a short-range interaction fine-tuned to a -wave resonance. We show that three such fermions form an infinite tower of bound states of orbital angular momentum and their binding energies obey a universal doubly exponential scaling at large . This “super Efimov effect” is found by a renormalization group analysis and confirmed by solving the bound state problem. We also provide an indication that there are four-body resonances associated with every three-body bound state at . These universal few-body states may be observed in ultracold atom experiments and should be taken into account in future many-body studies of the system.
- Received 18 January 2013
DOI:https://doi.org/10.1103/PhysRevLett.110.235301
© 2013 American Physical Society