BEC-BCS crossover, phase transitions and phase separation in polarized resonantly-paired superfluids

Abstract

We study resonantly-paired s-wave superfluidity in a degenerate gas of two species (hyperfine states labeled by $\uparrow ,\downarrow$) of fermionic atoms when the numbers $N_{\uparrow }$ and $N_{\downarrow }$ of the two species are {\it unequal}, i.e., the system is "polarized". We find that the continuous crossover from the Bose-Einstein condensate (BEC) limit of tightly-bound diatomic molecules to the Bardeen-Cooper-Schrieffer (BCS) limit of weakly correlated Cooper pairs, studied extensively at equal populations, is interrupted by a variety of distinct phenomena under an imposed population difference $\Delta N\equiv N_{\uparrow }-N_{\downarrow }$. Our findings are summarized by a `` polarization\rq\rq ($\Delta N$) versus Feshbach-resonance detuning ($\delta$) zero-temperature phase diagram, which exhibits regions of phase separation, a periodic FFLO superfluid, a polarized normal Fermi gas and a polarized molecular superfluid consisting of a molecular condensate and a fully polarized Fermi gas. We describe numerous experimental signatures of such phases and the transitions between them, in particular focusing on their spatial structure in the inhomogeneous environment of an atomic trap.

76 RevTeX pages, 54 figures. Corrected typos. PRB two-column format. To appear in Annals of Physics (already available online at AOP website)

References in corpus (16)

• Vortices and Superfluidity in a Strongly Interacting Fermi Gas
• Observation of the Pairing Gap in a Strongly Interacting Fermi Gas
• Weakly bound dimers of fermionic atoms
• Collective excitations of a degenerate gas at the BEC-BCS crossover
• Observation of Phase Separation in a Strongly-Interacting Imbalanced Fermi Gas
• Molecular Probe of Pairing in the BEC-BCS Crossover
• Phase diagram of a cold polarized Fermi gas
• Mean field phase diagrams of imbalanced Fermi gases near a Feshbach resonance
• Nonequilibrium dynamics and thermodynamics of a degenerate Fermi gas across a Feshbach resonance
• Induced P-wave Superfluidity in Asymmetric Fermi Gases
• BCS-BEC crossover in an asymmetric two-component Fermi gas
• Realization and Detection of Fulde-Ferrell-Larkin-Ovchinnikov Superfluid Phases in Trapped Atomic Fermion Systems
• Phase diagram of a polarized Fermi gas across a Feshbach resonance in a potential trap
• Fermi surfaces and Luttinger's theorem in paired fermion systems
• Asymmetric Fermi superfluid in a harmonic trap
• Ultracold polarized Fermi gas at intermediate temperatures

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• Normal-Superfluid Interface for Polarized Fermion Gases
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• Superfluid-Insulator Transition and Fermion Pairing in Bose-Fermi Mixtures
• Temperature Effects in a Fermi Gas with Population Imbalance
• Polarized superfluids near their tricritical point
• Unconventional interaction between vortices in a polarized Fermi gas
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