Efimov physics in the presence of a Fermi sea

I will introduce the Efimov correlation in atomic system of two heavy bosons (¹³³Cs) immersed in a bath of light fermions (⁶Li). Using the Born-Oppenheimer approximation, we identify two different regimes, depending on the Fermi momentum of light fermions ( k_F ) and the boson-fermion scattering length a_s(< 0), where the presence of underlying Fermi sea plays distinct roles in the Efimov-type binding of bosons. Namely, in the regime k_F |a_s| < 1 ( k_F |a_s| > 1 ), the Fermi sea induces an attractive (repulsive) effective interaction between bosons and thus favors (disfavors) the formation of bound state, which can be seen as the Efimov trimer dressed by the fermion cloud. Interestingly, this implies a non-monotonic behavior of these bound states as increasing the fermion density (or k_F ). Moreover, we establish a generalized universal scaling law for the emergence/variation of such dressed Efimov bound states when incorporating a new scale ( k_F ) brought by the Fermi sea.