All-optical production of dual Bose–Einstein condensates of paired fermions and bosons with<sup>6</sup>Li and<sup>7</sup>Li

Ikemachi, Takuya; Ito, Aki; Aratake, Yukihito; Koashi, Masato; Kuwata‐Gonokami, Makoto; Horikoshi, Munekazu

doi:10.1088/1361-6455/50/1/01lt01

Cited by 23 publications

(22 citation statements)

References 31 publications

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“…This magnetic trap works mainly along the z direction because the ODT provides much stronger confinement than the magnetic trap along the x and y directions. Typically, 5 × 10 5 degenerate fermions are prepared in a trap with a depth of 38 µK and trapping frequencies of (ω x , ω y , ω z )=2π×(250, 232, 7.08) Hz [17].…”

Section: Discussionmentioning

confidence: 99%

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Appropriate Probe Condition for Absorption Imaging of Ultracold⁶Li Atoms

et al. 2017

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One of the readily accessible observables in trapped cold-atom experiments is the column density, which is determined from optical depth (OD) obtained from absorption imaging and the absorption cross-section (σ abs ). Here we report on simple and accurate determination of OD for dense gases of light atoms such as lithium-6. We investigate theoretically and experimentally an appropriate condition for the probe intensity and duration to achieve good signal-to-noise ratio by considering the influences of photon recoils and photon shot noises. As a result, we have succeeded in measuring OD which reached 2.5 with a signal-to-noise ratio of 10 under spatial resolution of 1.7 µm.

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Section: Discussionmentioning

confidence: 99%

“…(B.12) for the present trap configuration [30]. In the experiment, the trapping potential is given by a combination of an ODT (U ODT ) and a magnetic trap (U mag ) [17]. As noted in Sec.…”

Section: Figures B2(a) and (B) Show Absorption Images Of State |1mentioning

confidence: 99%

Appropriate Probe Condition for Absorption Imaging of Ultracold⁶Li Atoms

et al. 2017

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“…The recent experimental realization of a mixture of Bose and Fermi superfluids in ultracold atoms has generated much interest in the properties of this new state of matter [1][2][3][4][5][6], and led to a surge of theoretical activity [7][8][9][10][11][12][13][14][15][16][17][18]. Collective excitations that characterize a system's response to small perturbations constitute one of the main sources of information for understanding the physics of many-body systems [19,20].…”

Section: Introductionmentioning

confidence: 99%

Collective oscillation modes of a superfluid Bose–Fermi mixture

Wen

Wang

2019

New J. Phys.

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In this work, we present a theoretical study for the collective oscillation modes, i.e. quadrupole, radial and axial mode, of a mixture of Bose and Fermi superfluids in the crossover from a Bardeen-Cooper-Schrieffer (BCS) superfluid to a molecular Bose-Einstein condensate (BEC) in harmonic trapping potentials with cylindrical symmetry of experimental interest. To this end, we start from the coupled superfluid hydrodynamic equations for the dynamics of Bose-Fermi superfluid mixtures and use the scaling theory that has been developed for a coupled system. The collective oscillation modes of Bose-Fermi superfluid mixtures are found to crucially depend on the overlap integrals of the spatial derivations of density profiles of the Bose and Fermi superfluids at equilibrium. We not only present the explicit expressions for the overlap density integrals, as well as the frequencies of the collective modes provided that the effective Bose-Fermi coupling is weak, but also test the valid regimes of the analytical approximations by numerical calculations in realistic experimental conditions. In the presence of a repulsive Bose-Fermi interaction, we find that the frequencies of the three collective modes of the Bose and Fermi superfluids are all upshifted, and the change speeds of the frequency shifts in the BCS-BEC crossover can characterize the different groundstate phases of the Bose-Fermi superfluid mixtures for different trap geometries. superfluid mixtures of 7 Li-6 Li [1, 2], 41 K-6 Li [6], and 174 Yb-6 Li [5], and the Bose-Fermi interaction gives rise to a rich behavior. In the presence of a repulsive Bose-Fermi interaction, the frequencies of the dipole oscillations of the Bose and Fermi superfluids are both downshifted in the weakly confined direction [1,5,6], and the frequency shifts increase monotonically from the BCS side to the BEC side [48,49]. In contrast, the frequency in the tight confinement for the Bose superfluid is upshifted, whereas the frequency for the Fermi superfluid is still downshifted [6]. The frequency shifts show non-monotonic and resonantlike behaviors in both directions around the BCS side [6], which may be originated from the effects of fermionic pairs breaking [50].It is naturally to ask how Bose-Fermi interaction affects the collective modes of Bose and Fermi superfluids in the BCS-BEC crossover, which is of great interest recently. However, a theoretical study for the collective oscillation modes of Bose-Fermi superfluid mixtures in a realistic experimental situation is highly nontrivial. In this work, to study quadrupole, radial and axial modes in cylindrically symmetric traps, we start from the coupled superfluid hydrodynamic equations describing the dynamics of the Bose-Fermi superfluid mixtures. The scaling method for coupled systems is then applied, and the eigenvalue equations for the coupled collective modes are obtained, which are crucially sensitive to the overlap integrals of the spatial derivations of the Bose and Fermi densities at groundstate. To present the explicit expressio...

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“…The recent experimental realization of mixtures of Bose and Fermi superfluids in ultra-cold atoms advances an essential step to explore double superfluidity belonging to different statistics [1,2], which is a long-sought goal in liquid helium, and opens a new scenario for the physics of superfluid mixtures [3][4][5][6]. Motivated by the breakthrough experiments [1][2][3][4][5][6], many theoretical studies have been done, such as Chandrasekhar-Clogston critical polarization [7], atom-dimer scattering properties [8,9], quasiparticle excitation [10,11], counterflow instability [12], dark-bright soliton [13], and vortex [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Collective dipole oscillations in a mixture of Bose and Fermi superfluids in the BCS–BEC crossover

Wen

2018

New J. Phys.

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We present a study for the collective dipole oscillations of a mixture of Bose and Fermi superfluids in the crossover from Bardeen-Cooper-Schrieffer (BCS) superfluid to a molecular Bose-Einstein condensate (BEC) in the ENS experimental setup (Ferrier-Barbut et al 2014 Science 345 1035). The dynamics of the double superfluidity is described by coupled time-dependent order-parameter equations, which are Gross-Pitaevskii equations for the Bose superfluid, coupled to the orderparameter equation including the equation of state fitting from the experimental data for the Fermi superfluid in the BCS-BEC crossover. The numerical simulations show that due to the boson-fermion interaction, the frequencies of the dipole oscillations of the Bose and Fermi superfluids are both downshifted and the frequency shifts increase monotonically from the BCS side to BEC side, which are in agreement with the experiment. We further study the dependencies of the frequency shifts on the oscillation amplitudes and the nonlinear effects, in which the Bose and Fermi superfliuds show different features. The frequency shifts of the Bose superfluid increase linearly as the oscillation amplitudes increase, while the frequency shifts of the Fermi superfluid show a quadratical increase. It is found that the intrinsic dipole oscillations of the Bose (Fermi) superfluid can be triggered by only boosting the Fermi (Bose) superfluid.

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All-optical production of dual Bose–Einstein condensates of paired fermions and bosons with⁶Li and⁷Li

Cited by 23 publications

References 31 publications

Appropriate Probe Condition for Absorption Imaging of Ultracold⁶Li Atoms

Appropriate Probe Condition for Absorption Imaging of Ultracold⁶Li Atoms

Collective oscillation modes of a superfluid Bose–Fermi mixture

Collective dipole oscillations in a mixture of Bose and Fermi superfluids in the BCS–BEC crossover

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All-optical production of dual Bose–Einstein condensates of paired fermions and bosons with6Li and7Li

Cited by 23 publications

References 31 publications

Appropriate Probe Condition for Absorption Imaging of Ultracold6Li Atoms

Appropriate Probe Condition for Absorption Imaging of Ultracold6Li Atoms

Collective oscillation modes of a superfluid Bose–Fermi mixture

Collective dipole oscillations in a mixture of Bose and Fermi superfluids in the BCS–BEC crossover

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All-optical production of dual Bose–Einstein condensates of paired fermions and bosons with⁶Li and⁷Li

Appropriate Probe Condition for Absorption Imaging of Ultracold⁶Li Atoms

Appropriate Probe Condition for Absorption Imaging of Ultracold⁶Li Atoms