Feshbach resonances in ultracold 85Rb-87Rb and 6Li-87Rb mixtures

TL;DR

This paper analyzes and models magnetic Feshbach resonances in ultracold heteronuclear 85Rb-87Rb and 6Li-87Rb mixtures, predicting resonance locations to aid experimental control in quantum systems.

Contribution

It develops accurate potential models for these mixtures based on recent experimental data, predicting new resonances at low magnetic fields for quantum applications.

Findings

Resonances occur below 10 G in magnetic field.

Models accurately reproduce known resonances.

Predicted resonances can facilitate entanglement in quantum traps.

Abstract

We present an analysis of experimentally accessible magnetic Feshbach resonances in ultra-cold hetero-nuclear 85Rb-87Rb and 6Li-87Rb mixtures. Using recent experimental measurements of the triplet scattering lengths for 6Li-87Rb and 7Li-87Rb mixtures and Feshbach resonances for one combination of atomic states, we create model potential curves and fine tune them to reproduce the measured resonances and to predict the location of several experimentally relevant resonances in Li-Rb collisions. To model 85Rb-87Rb collisions, we use accurate Rb_2 potentials obtained previously from the analysis of experiments on 87Rb-87Rb collisions. We find resonances that occur at very low magnetic fields, below 10 G, which may be useful for entanglement generation in optical lattices or atom chip magnetic traps.