Three in Many: Efimov physics in the presence of a Fermi sea

Abstract

Motivated by recent experiments on ${}^6$Li-${}^{133}$Cs atomic mixtures with high mass imbalance, we study the Efimov correlation in atomic system of two heavy bosons (${}^{133}$Cs) immersed in a bath of light fermions (${}^6$Li). 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 $k_F|a_s|\lesssim 1$ ($k_F|a_s|\gtrsim 1$), 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. These results can be directly tested in Li-Cs cold atoms experiment by measuring the modified bound state spectrum and the shifted Efimov resonance, which manifest an emergent non-trivial Efimov correlation in a fermionic many-body environment.

6 pages, 4 figures

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• Fermion-mediated interactions in a dilute Bose-Einstein condensate
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Cited by in corpus (7)

• Cooper Triples in Attractive Three-Component Fermions: Implication for Hadron-Quark Crossover
• Condensation of Cooper Triples
• Three-body crossover from a Cooper triple to bound trimer state in three-component Fermi gases near a triatomic resonance
• Medium-induced bosonic clusters in a Bose-Fermi mixture: Towards simulating cluster formations in neutron-rich matter
• Interferometry of Efimov states in thermal gases by modulated magnetic fields
• Competing few-body correlations in ultracold Fermi polarons
• Non-equilibrium dynamics and atom-pair coherence in strongly interacting Bose-Fermi mixtures