Double Microwave Shielding

TL;DR

This paper introduces a double microwave shielding technique that uses two microwave fields to suppress losses and control interactions in ultracold polar molecules, facilitating advanced studies of dipolar quantum matter.

Contribution

It provides a detailed theoretical framework for double microwave shielding, demonstrating its effectiveness and universality in controlling interactions in ultracold polar molecules.

Findings

Suppresses two- and three-body losses effectively

Enables tuning of dipolar interactions and scattering length

Universal applicability across various polar molecules

Abstract

We develop double microwave shielding, which has recently enabled evaporative cooling to the first Bose-Einstein condensate of polar molecules [Bigagli et al., Nature 631, 289 (2024)]. Two microwave fields of different frequency and polarization are employed to effectively shield polar molecules from inelastic collisions and three-body recombination. Here, we describe in detail the theory of double microwave shielding. We demonstrate that double microwave shielding effectively suppresses two- and three-body losses. Simultaneously, dipolar interactions and the scattering length can be flexibly tuned, enabling comprehensive control over interactions in ultracold gases of polar molecules. We show that this approach works universally for a wide range of molecules. This opens the door to studying many-body physics with strongly interacting dipolar quantum matter.