Abstract
We treat small trapped unequal-mass two-component Fermi gases at unitarity within a nonperturbative microscopic framework and investigate the system properties as functions of the mass ratio , and the numbers and of heavy and light fermions. While equal-mass Fermi gases with infinitely large interspecies -wave scattering length are universal, we find that unequal-mass Fermi gases are, for sufficiently large and in the regime where Efimov physics is absent, not universal. In particular, the and (3, 1) systems exhibit three-body and four-body resonances at and 10.4(2), respectively, as well as surprisingly large finite-range effects. These findings have profound implications for ongoing experimental efforts and quantum simulation proposals that utilize unequal-mass atomic Fermi gases.
- Received 25 June 2010
DOI:https://doi.org/10.1103/PhysRevLett.105.170403
© 2010 The American Physical Society