Nature of 3D Bose gases near Feshbach Resonance

we explore the nature of 3D Bose gases at large positive scattering lengths via resummation of dominating processes involving a minimum number of virtual atoms. We focus on the energetics of Bose gases beyond the usual dilute limit. We also ?nd that an onset instability sets in at a critical scattering length beyond which the near-resonance Bose gases become strongly coupled to molecules and lose the metastability. Near the point of instability, the chemical potential reaches a maximum and the e?ect of the three-body forces can be estimated to be within a few percent.