Reshaped three-body interactions and the observation of an Efimov state in the continuum.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38459026.
- Also identified by DOI 10.1038/s41467-024-46353-1 and PMC identifier 10923905.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
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 <sup>7</sup>Li atoms using a narrow two-body Feshbach resonance. Contrary to the expectation, we find that the <sup>7</sup>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 <sup>7</sup>Li Efimov states and provide a path to understand various puzzling phenomena associated with them.