Polarons in Ultracold Fermi Superfluids

Abstract

We study a new type of Fermi polaron induced by an impurity interacting with an ultracold Fermi superfluid. Due to the three-component nature of the system, the polaron can become trimer-like with a non-universal energy spectrum. We identify multiple avoided crossings between impurity- and trimer-like solutions in both the attractive and the repulsive polaron spectra. In particular, the widths of avoided crossings gradually increase as the Fermi superfluid undergoes a crossover from the BCS side towards the BEC side, which suggests instabilities towards three-body losses. Such losses can be reduced for interaction potentials with small effective ranges. We also demonstrate, using the second-order perturbation theory, that the mean-field evaluation of the fermion-impurity interaction energy is inadequate even for small fermion-impurity scattering lengths, due to the essential effects of Fermi superfluid and short-range physics in such a system. Our results are practically useful for cold atom experiments on mixtures.

7 pages, 6 figures, updated with the published version

References in corpus (14)

• Observation of Fermi Polarons in a Tunable Fermi Liquid of Ultracold Atoms
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• Normal state of a polarized Fermi gas at unitarity
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• Normal state of highly polarized Fermi gases: Full many-body treatment
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• Trimers, molecules and polarons in imbalanced atomic Fermi gases
• Self-trapping of impurities in Bose-Einstein condensates: Strong attractive and repulsive coupling
• Polaronic atom-trimer continuity in three-component Fermi gases
• Casimir interaction among heavy fermions in the BCS-BEC crossover
• Pauli Blocking Effect on Efimov States Near Feshbach Resonance
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• Atom-Dimer Scattering and Stability of Bose and Fermi Mixtures

Cited by in corpus (14)

• Finite-temperature behavior of the Bose polaron
• Enhancing the Efimov correlation in Bose polarons with large mass imbalance
• Polarons and Molecules in a Fermi Gas with Orbital Feshbach Resonance
• Quantum droplet in a mixture of Bose-Fermi superfluids
• Hartree-Fock treatment of Fermi polarons using the Lee-Low-Pine transformation
• Probing the dynamic structure factor of a neutral Fermi superfluid along the BCS-BEC crossover using atomic impurity qubits
• Universal trimers emerging from a spin-orbit coupled Fermi sea
• Three in Many: Efimov physics in the presence of a Fermi sea
• Polaron in a $p+ip$ Fermi topological superfluid
• Exact results for polaron and molecule in one-dimensional spin-1/2 Fermi gas
• An impurity immersed in a double Fermi Sea
• A mixed dimensional Bose polaron
• Mean-field vs RPA calculation of the energy of an impurity immersed in a spin 1/2 superfluid
• Bose polaron in spherically symmetric trap potentials: Ground states with zero and lower angular momenta