Controlling few-body reaction pathways using a Feshbach resonance

TL;DR

This paper presents a new method to control three-body recombination reactions at the quantum level using a magnetically-tunable Feshbach resonance, enabling selective manipulation of reaction products in ultracold chemistry.

Contribution

The authors introduce a novel technique employing Feshbach resonances to coherently steer reaction pathways and control product spin channels in ultracold three-body reactions.

Findings

Feshbach resonance can selectively enhance specific reaction channels.

Efimov resonance increases overall recombination but does not alter channel ratios.

The control scheme is adaptable to other reaction processes.

Abstract

Gaining control over chemical reactions on the quantum level is a central goal of the modern field of cold and ultracold chemistry. Here, we demonstrate a novel method to coherently steer reaction flux of a three-body recombination process across different product spin channels. For this, we employ a magnetically-tunable Feshbach resonance to admix, in a controlled way, a specific spin state to the reacting collision complex. This allows for the control of the reaction flux into the admixed spin channel, which can be used to significantly change the reaction products. Furthermore, we also investigate the influence of an Efimov resonance on the reaction dynamics. We find that while the Efimov resonance can be used to globally enhance three-body recombination, the relative flux between the reaction channels remains unchanged. Our control scheme is general and can be extended to other reaction processes. It also provides new opportunities in combination with other control schemes, such as quantum interference of reaction paths.