Screening of the interaction between fermionic polarons

We study the induced interaction between heavy atoms immersed in a light Fermi sea. We show that when the density of the light fermions is large enough, the induced interaction between $N$ heavy atoms is screened and the heavy atoms behave as independent quasi-particles. We also show that the $N$-body Efimov effect is suppressed for any $N$ in the dense Fermi sea limit.