Universal Fermi Gas with Two- and Three-Body Resonances

TL;DR

This paper explores a universal Fermi gas with tunable two- and three-body resonances, revealing scale-invariant properties and strong interactions near critical mass ratios, with potential experimental realizations.

Contribution

It introduces a scale-invariant Fermi gas system with three-body resonances at specific mass ratios, deriving exact relationships and discussing experimental possibilities.

Findings

Ground state energy less than 2% of noninteracting gas near critical mass ratio

Exact pressure relationships near resonance points

Potential realization with cold atom experiments

Abstract

We consider a Fermi gas with two components of different masses, with the s-wave two-body interaction tuned to unitarity. In the range of mass ratio 8.62<M/m<13.6, it is possible for a single contact interaction between heavy fermions to produce a resonance in a three-body channel. The resulting system is scale invariant and has universal properties, and is very strongly interacting. When M/m is slightly above the lower limit 8.62, the ground state energy of a 2:1 mixture of heavy and light fermions is less than 2% of the energy of a noninteracting gas with the same number densities. We derive exact relationships between the pressures of the unitary Fermi gases with and without three-body resonance when the mass ratio is close to the critical values of 8.62 and 13.6. Possible experimental realization with cold atoms in optical lattices is discussed.