Analytical theory of the dressed bound state in highly polarized Fermi gases

We present an analytical treatment of a single ↓-atom within a Fermi sea of ↑-atoms, when the interaction is strong enough to produce a bound state, dressed by the Fermi sea. Our method makes use of a diagrammatic analysis, with the involved diagrams taking only into account at most two particle-hole pairs excitations. The agreement with existing Monte Carlo results is excellent. In the BEC limit our equation reduces exactly to the Skorniakov and Ter-Martirosian equation. We present results for ↑- and ↓-atoms with different masses, which is of interest for experiments in progress.