Shifts and widths of Feshbach resonances in atomic waveguides

TL;DR

This paper presents a theoretical model for calculating the shifts and widths of Feshbach resonances in atomic waveguides, considering multichannel interactions and various resonance types, enabling more accurate analysis of ultracold atomic scattering.

Contribution

It introduces a multichannel tensorial potential model for Feshbach resonances in waveguides, extending beyond s-wave interactions and incorporating experimental parameters.

Findings

Resonance width depends linearly on atomic momentum.

Resonance width depends quadratically on waveguide width.

The model predicts shifts and widths for Cs atom resonances in harmonic waveguides.

Abstract

We develop and analyze a theoretical model which yields the shifts and widths of Feshbach resonances in an atomic waveguide. It is based on a multichannel approach for confinement-induced resonances (CIRs) and atomic transitions in the waveguides in the multimode regime. We replace in this scheme the single-channel scalar interatomic interaction by the four-channel tensorial potential modeling resonances of broad, narrow and overlapping character according to the two-channel parametrization of A.D.Lange et al. As an input the experimentally known parameters of Feshbach resonances in the absence of the waveguide are used. We calculate the shifts and widths of s-, d- and g-wave magnetic Feshbach resonances of Cs atoms emerging in harmonic waveguides as CIRs and resonant enhancement of the transmission at zeros of the free space scattering length. We have found the linear dependence of the width of the resonance on the longitudinal atomic momentum and quadratic dependence on the waiveguide width. Our model opens novel possibilities for quantitative studies of the scattering processes in ultracold atomic gases in waveguides beyond the framework of s-wave resonant scattering.