2008/09/30 by Stefan Floerchinger, S. Floerchinger, R. Schmidt +4
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Physics of Superconductivity and Magnetism #Quantum, superfluid, helium dynamics #cond-mat.supr-con
paper · pdf · doi:10.1103/physreva.79.013603
published as Phys. Rev. A 79, 013603 (2009) · 9 pages, 4 figures, minor changes, reference added
openalex publication_date 2009/01/06 · arxiv created 2009/01/17 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The energy spectrum for three species of identical fermionic atoms close to a Feshbach resonance is computed by use of a nonperturbative flow equation. Already a simple truncation shows that for large scattering length \ensuremath|a\ensuremath| the lowest energy state is a ``trion'' (or trimer) bound state of three atoms. At the location of the resonance, for \ensuremath|a\ensuremath|\ensuremath→\ensuremath∞, we find an infinite set of trimer bound states, with exponentially decreasing binding energy. This feature was pointed out by Efimov [V. Efimov, Phys. Lett. 33B, 563 (1970)]. It arises from limit cycle scaling, which also leads to a periodic dependence of the three body scattering coupling on ln\ensuremath|a\ensuremath|. Extending our findings by continuity to nonzero density and temperature we find that a ``trion phase'' separates a Bose-Einstein condensate (BEC) and a BCS phase, with interesting quantum phase transitions for T=0.