Mott-Insulator-Aided Detection of Ultra-Narrow Feshbach Resonances

Abstract

We report on the detection of extremely narrow Feshbach resonances by employing a Mott-insulating state for cesium atoms in a three-dimensional optical lattice. The Mott insulator protects the atomic ensemble from high background three-body losses in a magnetic field region where a broad Efimov resonance otherwise dominates the atom loss in bulk samples. Our technique reveals three ultra-narrow and previously unobserved Feshbach resonances in this region with widths below $\approx 10\mu$G, measured via Landau-Zener-type molecule formation and confirmed by theoretical predictions. For comparatively broader resonances we find a lattice-induced substructure in the respective atom-loss feature due to the interplay of tunneling and strong particle interactions. Our results provide a powerful tool to identify and characterize narrow scattering resonances, particularly in systems with complex Feshbach spectra. The observed ultra-narrow Feshbach resonances could be interesting candidates for precision measurements.

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• A Mott Insulator of Ultracold Alkaline-Earth-Like Atoms
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Cited by in corpus (13)

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• Feshbach resonances in $p$-wave three-body recombination within Fermi-Fermi mixtures of open-shell ${}^6$Li and closed-shell ${}^{173}$Yb atoms
• Many-body Chemical Reactions in a Quantum Degenerate Gas
• Two-photon photoassociation spectroscopy of the ${}^2{\Sigma }^{+}$ YbLi molecular ground state
• Observation of confinement-induced resonances in a 3D lattice
• Prospects of forming high-spin polar molecules from ultracold atoms
• Spin dynamics dominated by superexchange via virtual molecules
• Feshbach Spectroscopy of Cs Atom Pairs in Optical Tweezers
• Precise Feshbach resonance spectroscopy using tight anharmonic traps
• Droplets of Bosons at a Narrow Resonance
• First-order phase transition in atom-molecule quantum degenerate mixtures with coherent three-body recombination