Reaching a Fermi-superfluid state near an orbital Feshbach resonance

Xu, Junjun; Zhang, Ren; Cheng, Yanting; Zhang, Peng; Qi, Ran; Zhai, Hui

doi:10.1103/physreva.94.033609

Cited by 38 publications

(55 citation statements)

References 28 publications

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“…In particular, it is no longer admissible to treat the closed channel state as a single boson without taking into account of its proper internal dynamics. One is thus lead to a situation much the same as a two-band superconductor, where the appropriate picture is that two Fermi surfaces (including both spin) intersect the chemical potential [18][19][20]. We show that this new situation leads to the appearance of new collective modes and in particular, the long-sought Leggett mode in the two-band superconductor.…”

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confidence: 97%

Collective modes in a two-band superfluid of ultracold alkaline-earth-metal atoms close to an orbital Feshbach resonance

2017

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We discuss the collective modes in an alkaline-earth Fermi gas close to an orbital Feshbach resonance. Unlike the usual Feshbach resonance, the orbital Feshbach resonance in alkaline-earth atoms realizes a two-band superfluid system where the fermionic nature of both the open and the closed channel has to be taken into account. We show that apart from the usual Anderson-Bogoliubov mode which corresponds to the oscillation of total density, there also appears the long-sought Leggett mode corresponding to the oscillation of relative density between the two channels. The existence of the phonon and the Leggett modes and their evolution are discussed in detail. We show how these collective modes are reflected in the density response of the system. [5][6][7], is that there are two clock states, the electronic s-and p-states, both of which have zero electronic angular momentum J = 0. As a result, there is no hyperfine coupling between the electronic and nuclear spins. The inter-atomic interactions which depend (primarily) on the electronic configurations thus become independent of nuclear spins. This realizes the so-called SU (N ) symmetries, where N is the number of nuclear spin components [8][9][10][11][12][13][14][15]. The OFR relies on the atoms residing on both the s and p-states which possess slight different Landé g-factors [16,17], thus allowing tuning by external magnetic field.

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confidence: 97%

Collective modes in a two-band superfluid of ultracold alkaline-earth-metal atoms close to an orbital Feshbach resonance

2017

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“…This would enable us to control the interactions between the two internal states by using the recently discovered 173 Yb orbital Feshbach resonance [36][37][38]. This would allow the investigation of synthetic flux ladders with tunable interleg interactions, and could be used to investigate SOC in atomic 173 Yb Fermi superfluids at the BEC-BCS crossover [39,40], e.g., to study the possible emergence of topological superfluidity. In the SD approach, we envision the possibility of combining the nuclear spin SD with the electronic SD, realizing multidimensional synthetic lattice structures with nontrivial connectivities [41,42], periodic boundary conditions, and engineered topological properties thanks to the control of the tunneling phases.…”

Section: H Y S I C a L R E V I E W L E T T E R S Week Ending 25 Novemmentioning

confidence: 99%

Synthetic Dimensions and Spin-Orbit Coupling with an Optical Clock Transition

et al. 2016

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We demonstrate a novel way of synthesizing spin-orbit interactions in ultracold quantum gases, based on a single-photon optical clock transition coupling two long-lived electronic states of two-electron 173 Yb atoms. By mapping the electronic states onto effective sites along a synthetic "electronic" dimension, we have engineered fermionic ladders with synthetic magnetic flux in an experimental configuration that has allowed us to achieve uniform fluxes on a lattice with minimal requirements and unprecedented tunability. We have detected the spin-orbit coupling with fiber-link-enhanced clock spectroscopy and directly measured the emergence of chiral edge currents, probing them as a function of the flux. These results open new directions for the investigation of topological states of matter with ultracold atomic gases. DOI: 10.1103/PhysRevLett.117.220401 Ultracold atoms are emerging as a very versatile platform for the investigation of topological states of matter [1], thanks to the possibility of using laser light to synthesize artificial gauge fields [2,3] and to engineer lattices with topological band structures [4][5][6][7][8]. A prime element for the emergence of nontrivial topological properties is the presence of spin-orbit coupling (SOC) [9,10], locking the spin of the particles to their motion. This interaction was first synthesized in cold atomic gases by using twophoton Raman transitions [11] coupling two hyperfine spin states with a transfer of momentum. The coupling between spin states also enables a new powerful tool for engineering topological states of matter, which relies on the "synthetic dimension" (SD) concept [12,13]. According to this approach, the internal states of an atom are treated as effective sites along a synthetic lattice dimension, and coherent coupling between them is interpreted in terms of an effective tunneling. This idea has recently been realized in Refs. [14,15], where synthetic flux ladders have been implemented by using the spin degree of freedom, and has allowed the first observation of chiral edge states in ultracold atomic systems. Its extension has inspired several proposals, opening the way, e.g., to the observation of new quantum states [16,17], to the detection of fractional charge pumping [18,19], or to the observation of the four-dimensional quantum Hall effect [20].In this Letter, we demonstrate that SOC and SDs can be efficiently implemented by exploiting different degrees of freedom, specifically, the long-lived electronic state of alkaline-earth(-like) atoms. By using the technology developed in the context of optical atomic clocks, we induce a coherent coupling between the ground state g ¼ 1 S 0 and the metastable state e ¼ 3 P 0 (lifetime ∼20 s) of ultracold 173 Yb atoms. Since the two states are separated by an optical energy, it is possible to have a sizable transfer of momentum with a single-photon transition, as pointed out An ultranarrow clock laser with wavelength λ C drives the singlephoton transition between the ground state g ¼ 1 S 0 and the long...

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“…As discussed in Ref. [31], under the ladder approximation, we may write down a set of coupled equations for the T-matrices, which lead to the solution Here, the pair propagators for the closed and the open channel χ c (q, ω) and χ o (q, ω) can be written as…”

Section: (A)mentioning

confidence: 99%

Repulsive polarons in alkaline-earth-metal-like atoms across an orbital Feshbach resonance

Deng¹,

Lu²,

Shi³

et al. 2018

Phys. Rev. A

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We characterize properties of the so-called repulsive polaron across the recently discovered orbital Feshbach resonance in alkaline-earth(-like) atoms. Being a metastable quasiparticle excitation at the positive energy, the repulsive polaron is induced by the interaction between an impurity atom and a Fermi sea. By analyzing in detail the energy, the polaron residue, the effective mass, and the decay rate of the repulsive polaron, we reveal interesting features that are intimately related to the two-channel nature of the orbital Feshbach resonance. In particular, we find that the life time of the repulsive polaron is non-monotonic in the Zeeman-field detuning bewteen the two channels, and has a maximum on the BEC-side of the resonance. Further, by considering the stability of a mixture of the impurity and the majority atoms against phase separation, we show that the itinerant ferromagnetism may exist near the orbital Feshbach resonance at appropriate densities. Our results can be readily probed experimentally, and have interesting implications for the observation of itinerant ferromagnetism near an orbital Feshbach resonance.

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Reaching a Fermi-superfluid state near an orbital Feshbach resonance

Cited by 38 publications

References 28 publications

Collective modes in a two-band superfluid of ultracold alkaline-earth-metal atoms close to an orbital Feshbach resonance

Collective modes in a two-band superfluid of ultracold alkaline-earth-metal atoms close to an orbital Feshbach resonance

Synthetic Dimensions and Spin-Orbit Coupling with an Optical Clock Transition

Repulsive polarons in alkaline-earth-metal-like atoms across an orbital Feshbach resonance

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