Efimov states embedded in the three-body continuum

TL;DR

This paper models three-atom systems near Feshbach resonances, predicting the existence of Efimov states embedded in the continuum, which could be observed spectroscopically to measure multiple Efimov resonances.

Contribution

It introduces a multichannel pseudopotential model to predict quasi-bound Efimov states attached to excited thresholds in three-atom systems.

Findings

Predicted series of quasi-bound Efimov states above open channel energies

Identified conditions for supporting these Efimov states

Suggested spectroscopic methods for observing multiple Efimov resonances

Abstract

We consider a multichannel generalization of the Fermi pseudopotential to model low-energy atom-atom interactions near a magnetically tunable Feshbach resonance, and calculate the adiabatic hyperspherical potential curves for a system of three such interacting atoms. In particular, our model suggests the existence of a series of quasi-bound Efimov states attached to excited three-body thresholds, far above open channel collision energies. We discuss the conditions under which such states may be supported, and identify which interaction parameters limit the lifetime of these states. We speculate that it may be possible to observe these states using spectroscopic methods, perhaps allowing for the measurement of multiple Efimov resonances for the first time.