Range Corrections to Three-Body Observables near a Feshbach Resonance

TL;DR

This paper investigates how finite-range corrections affect three-body observables near a Feshbach resonance, providing theoretical results relevant for experiments with Bose-Einstein condensates.

Contribution

It derives finite-range corrections to three-body bound states and recombination rates using effective theory, extending previous zero-range results to finite scattering lengths.

Findings

Finite-range corrections modify three-body spectra and recombination rates.

Results are applicable to experiments near Feshbach resonances in Bose-Einstein condensates.

Theoretical framework extends Efimov physics to include effective range effects.

Abstract

A non-relativistic system of three identical particles will display a rich set of universal features known as Efimov physics if the scattering length a is much larger than the range l of the underlying two-body interaction. An appropriate effective theory facilitates the derivation of both results in the |a| goes to infinity limit and finite-l/a corrections to observables of interest. Here we use such an effective-theory treatment to consider the impact of corrections linear in the two-body effective range, r_s on the three-boson bound-state spectrum and recombination rate for |a| much greater than |r_s|. We do this by first deriving results appropriate to the strict limit |a| goes to infinity in coordinate space. We then extend these results to finite a using once-subtracted momentum-space integral equations. We also discuss the implications of our results for experiments that probe three-body recombination in Bose-Einstein condensates near a Feshbach resonance.