Three-Body Recombination of Ultracold Microwave-Shielded Polar Molecules

TL;DR

This study combines experiments and classical modeling to understand three-body recombination in microwave-shielded polar molecules, revealing its role in observed loss rates and the importance of field-linked bound states.

Contribution

It provides a detailed classical trajectory model for three-body recombination into field-linked states, explaining experimental loss rates in microwave-shielded polar molecules.

Findings

Reproduces experimental three-body loss rates across various parameters.

Shows three-body recombination explains enhanced loss at small microwave detunings.

Highlights the significance of field-linked bound states in molecular loss processes.

Abstract

A combined experimental and theoretical study is carried out on the three-body recombination process in a gas of microwave-shielded polar molecules. For ground-state polar molecules dressed with a strong microwave field, field-linked bound states can appear in the intermolecular potential. We model three-body recombination into such bound states using classical trajectory calculations. Our results show that recombination can explain the enhanced loss rates observed at small microwave detunings in trapped samples of bosonic NaCs [Bigagli, $\textit{et al.}$, Nat. Phys. $\textbf{19}$ 1579-1584 (2023)]. Specifically, our calculations reproduce the experimentally measured three-body loss rates across a wide range of microwave Rabi couplings, detunings, and temperatures. This work suggests that for bosonic shielded molecular systems in which the two-body loss is sufficiently suppressed and a field-linked bound state is present, the dominant loss process will be three-body recombination.