Fermi-Bose mixture across a Feshbach resonance

Abstract

We study a dilute mixture of degenerate bosons and fermions across a Feshbach resonance of the Fermi-Fermi scattering length $a_F$. This scattering length is renormalized by the boson-induced interaction between fermions and its value is crucial to determine the phase diagram of the system. For the mixture in a box and a positive Bose-Fermi scattering length, we show that there are three possibilities: a single uniform mixed phase, a purely fermionic phase coexisting with a mixed phase, and a purely fermionic phase coexisting with a purely bosonic one. As $1/a_F$ is increased from a negative value to the Feshbach resonance ($1/a_F=0$) the region of pure separation increases and the other two regions are strongly reduced. Above the Feshbach resonance ($1/a_F>0$), pairs of Fermi atoms become Bose-condensed molecules. We find that these molecules are fully spatially separated from the bosonic atoms when $1/a_F$ exceedes a critical value. For a negative Bose-Fermi scattering length we deduce the condition for collapse, which coincides with the onset of dynamical instability of the fully mixed phase. We consider also the mixture in a harmonic trap and determine the conditions for partial demixing, full demixing and collapse. The experimental implications of our results are investigated by analyzing mixtures of ${}^6$Li--${}^{23}$Na and ${}^{40}$K--${}^{87}$Rb atoms.

9 pages, 5 figures, to be published in Phys. Rev. A

References in corpus (48)

• Observation of a Strongly-Interacting Degenerate Fermi Gas of Atoms
• Vortices and Superfluidity in a Strongly Interacting Fermi Gas
• Observation of Bose-Einstein Condensation of Molecules
• Experimental Study of the BEC-BCS Crossover Region in Lithium 6
• Evidence for Superfluidity in a Resonantly Interacting Fermi Gas
• Weakly bound dimers of fermionic atoms
• Collective excitations of a degenerate gas at the BEC-BCS crossover
• Superfluid Fermi Gases with Large Scattering Length
• Equation of state of a Fermi gas in the BEC-BCS crossover: a quantum Monte Carlo study
• Two-species mixture of quantum degenerate Bose and Fermi gases
• Fermi-Bose quantum degenerate ^40 K - ^87 Rb mixture with attractive interaction
• Fermi systems with long scattering lengths
• Influence of Induced Interactions on the Superfluid Transition in Dilute Fermi Gases
• Zero-temperature phase diagram of binary boson-fermion mixtures
• Quantum Monte Carlo Studies of Superfluid Fermi Gases
• Phonon exchange in dilute Fermi-Bose mixtures: tailoring the Fermi-Fermi interaction
• BCS-BEC crossover at finite temperature for superfluid trapped Fermi atoms
• Bulk and Collective Properties of a Dilute Fermi Gas in the BCS-BEC Crossover
• Interaction-driven Dynamics of 40K / 87Rb Fermi-Bose Gas Mixtures in the Large Particle Number Limit
• Collective modes of trapped gases at the BEC-BCS crossover
• Collective modes and ballistic expansion of a Fermi gas in the BCS-BEC crossover
• Time-Dependent Density-Functional Theory for Trapped Strongly-Interacting Fermionic Atoms
• Quantitative comparison between theoretical predictions and experimental results for the BCS-BEC crossover
• Breakdown of Hydrodynamics in the Radial Breathing Mode of a Strongly-Interacting Fermi Gas
• Collective oscillations of a trapped Fermi gas near a Feshbach resonance
• A Degenerate Bose-Fermi Mixture of Metastable Atoms
• Ground-state properties of a dilute Bose-Fermi mixture
• Condensate Fraction of a Fermi Gas in the BCS-BEC Crossover
• Bose-Fermi Mixtures in One Dimension
• The Vortex State in a Strongly Coupled Dilute Atomic Fermionic Superfluid
• Component separation in harmonically trapped boson-fermion mixtures
• Mean-field analysis of the stability of a K-Rb Fermi-Bose mixture
• Oscillation Frequencies for a Bose Condensate in a Triaxial Magnetic Trap
• Ideal Quantum Gases in D-dimensional Space and Power-law Potentials
• Quantum field theory of dilute homogeneous Bose-Fermi-mixtures at zero temperature: general formalismand beyond mean-field corrections
• Mean-field description of dynamical collapse of a fermionic condensate in a trapped boson-fermion mixture
• Boson induced s-wave pairing in dilute boson-fermion mixtures
• Collective excitations in trapped boson-fermion mixtures: from demixing to collapse
• Thermodynamics of Multi-Component Fermi Vapors
• Normal modes and stability of phase separated trapped Bose-Einstein condensates
• Expansion of a Fermi Cloud in the BCS-BEC Crossover
• Pulsed Macroscopic Quantum Tunneling of Falling Bose Condensates
• Comment on "Collective excitations of a degenerate gas at the BEC-BCS crossover"
• Finite temperature effects on the collapse of trapped Bose-Fermi mixtures
• Ground-state properties of trapped Bose-Fermi mixtures: role of exchange-correlation
• Strong coupling theory for the superfluidity of Bose-Fermi mixtures
• Hydrodynamic Modes in a Trapped Strongly Interacting Fermi Gases of Atoms
• Statics and dynamics of phase segregation in multicomponent fermion gas

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• The demixing of the two-component fermions in optical lattices under a spin-dependent external potential
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• BCS and BEC p-wave pairing in Bose-Fermi gases
• Landau-Ginzburg Perspective of Finite-Temperature Phase Diagrams of a Two-Component Fermi-Bose Mixture
• Vortex-lattice structures in rotating Bose-Fermi superfluid mixtures