Atom-Dimer Scattering and Stability of Bose and Fermi Mixtures

Abstract

Motivated by a recent experiment by ENS group on the mixture of Bose and Fermi superfluids (arxiv:1404.2548), we investigate the effective scattering between a bosonic atom and a molecule(dimer) of fermion atoms. It is found that the mean-field prediction of the atom-dimer scattering length ($a_{ad}$), as simply given by the boson-fermion scattering length ($a_{bf}$), generically fails. Instead, $a_{ad}$ crucially depends on the ratio between $a_{bf}$ and $a_{ff}$ (the fermion-fermion scattering length), and in addition log-periodically depends on the three-body parameter. We identify the universal parameters in characterizing $a_{ad}$ for a wide range of $a_{ff}$ in the molecular side of the fermion-fermion Feshbach resonance, and further demonstrate that the atom-dimer many-body system can become unstable against either phase separation or collapse as tuning $a_{ff}$. Our results have some implications to the ENS experiment.

arXiv comment5+2 pages, 5 figures; accepted version by PRA(R)

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• Quasi-particle Lifetime in a Mixture of Bose and Fermi Superfluids
• Few vs many-body physics of an impurity immersed in a superfluid of spin 1/2 attractive fermions
• Quantum droplet in a mixture of Bose-Fermi superfluids
• Vortex Lattices in the Bose-Fermi Superfluid Mixture
• Landau Damping in a Mixture of Bose and Fermi Superfluids
• Atom-dimer scattering in heteronuclear mixture with finite intra-species scattering length
• Two-dimensional polaron spectroscopy of Fermi superfluids
• Weak-coupling to unitarity crossover in Bose-Fermi mixtures: Mixing-demixing and spontaneous symmetry breaking in trapped systems
• Detecting Entrainment in Fermi-Bose Mixtures
• Second root of dilute Bose-Fermi mixtures
• Elementary excitations in the hybrid Bose-Fermi system induced by circularly polarized light in a two-dimensional gas of charge carriers with different masses