Feshbach resonances in ultracold 85Rb

TL;DR

This paper reports the experimental discovery and analysis of 17 Feshbach resonances in ultracold 85Rb, including wide resonances useful for condensate formation and a narrow resonance in a spin mixture, supported by coupled-channels analysis.

Contribution

The study provides the first comprehensive experimental identification of multiple Feshbach resonances in 85Rb and detailed theoretical characterization, expanding control over ultracold rubidium systems.

Findings

17 Feshbach resonances confirmed in 85Rb

Wide resonances identified for condensate and few-body physics

Narrow resonance observed in a specific spin mixture

Abstract

We present 17 experimentally confirmed Feshbach resonances in optically trapped 85Rb. Seven of the resonances are in the ground-state channel (f,m_f) = (2,+2)+(2,+2), and nine are in the excited-state channel (2,-2)+(2,-2). We find a wide resonance at high field in each of the two channels, offering new possibilities for the formation of larger 85Rb condensates and studies of few-body physics. A detailed coupled-channels analysis is presented to characterize the resonances, and also provides an understanding of the inelastic losses observed in the excited-state channel. In addition we have confirmed the existence of one narrow resonance in a (2,+2)+(3,+3) spin mixture.