Reshaped Three-Body Interactions and the Observation of an Efimov State in the Continuum

Abstract

Efimov trimers are exotic three-body quantum states that emerge from the different types of three-body continua in the vicinity of two-atom Feshbach resonances. In particular, as the strength of the interaction is decreased to a critical point, an Efimov state merges into the atom-dimer threshold and eventually dissociates into an unbound atom-dimer pair. Here we explore the Efimov state in the vicinity of this critical point using coherent few-body spectroscopy in ${}^7$Li atoms using a narrow two-body Feshbach resonance. Contrary to the expectation, we find that the ${}^7$Li Efimov trimer does not immediately dissociate when passing the threshold, and survives as a metastable state embedded in the atom-dimer continuum. We identify this behavior with a universal phenomenon related to the emergence of a repulsive interaction in the atom-dimer channel which reshapes the three-body interactions in any system characterized by a narrow Feshbach resonance. Specifically, our results shed light on the nature of ${}^7$Li Efimov states and provide a path to understand various puzzling phenomena associated with them.

17 pages, 12 figures. arXiv admin note: text overlap with arXiv:2004.02723

References in corpus (20)

• Three-boson problem near a narrow Feshbach resonance
• Observation of universality in ultracold 7Li three-body recombination
• Observation of an Efimov-like resonance in ultracold atom-dimer scattering
• Radio Frequency Association of Efimov Trimers
• Analytical solution of the bosonic three-body problem
• Microscopic Origin and Universality Classes of the Efimov Three-Body Parameter
• Universal van der Waals Physics for Three Ultracold Atoms
• Study of Efimov physics in two nuclear-spin sublevels of 7Li
• Contrasting the wide Feshbach resonances in ${}^6$Li and ${}^7$Li
• Pinpointing Feshbach Resonances and Testing Efimov Universalities in ${}^{39}$K
• The multichannel nature of three-body recombination for ultracold ${}^{39}$K
• Strong spin-exchange recombination of three weakly interacting ${}^7$Li atoms
• A coherent superposition of Feshbach dimers and Efimov trimers
• Efimov scenario for overlapping narrow Feshbach resonances
• Efimovian three-body potential from broad to narrow Feshbach resonances
• Emergent inflation of the Efimov spectrum under three-body spin-exchange interactions
• A multichannel hyperspherical model for Efimov physics with van der Waals interactions controlled by a Feshbach resonance
• Efimov resonance position near a narrow Feshbach resonance in ${}^6$Li-${}^{133}$Cs mixture
• Interferometry of Efimov states in thermal gases by modulated magnetic fields
• Loosely Bound Few-Body States in a Spin-1 Gas with Near-Degenerate Continua

Cited by in corpus (10)

• Three-body forces and Efimov physics in nuclei and atoms
• Emergent inflation of the Efimov spectrum under three-body spin-exchange interactions
• Observation of a Halo Trimer in an Ultracold Bose-Fermi Mixture
• Closed-channel parameters of Feshbach resonances
• Density effects on the interferometry of Efimov states by modulating magnetic fields
• Accurate simulation of Efimov physics in ultracold atomic gases with realistic three-body multichannel interactions
• Universal spectrum of isolated three-body resonances
• Characterization of Feshbach resonances in ${}^6\mathrm{Li}{-}^7\mathrm{Li}$ using improved interaction potentials
• Universality in Ionic Three-body Systems Near an Ion-atom Feshbach Resonance
• Stabilization of three-body resonances to bound states in a continuum