Production of ultracold NH molecules by sympathetic cooling with Mg

TL;DR

This study investigates the potential for sympathetic cooling of ultracold NH molecules using Mg atoms, showing favorable elastic-to-inelastic collision ratios at low temperatures, which could enable efficient cooling to ultracold regimes.

Contribution

The paper provides theoretical calculations demonstrating the feasibility of sympathetic cooling of NH molecules with Mg atoms based on collision rate analysis.

Findings

Elastic collision rates exceed inelastic rates up to 10 mK.

The elastic-to-inelastic ratio improves at lower temperatures and magnetic fields.

Sympathetic cooling of NH with Mg is a promising method for reaching ultracold temperatures.

Abstract

We carry out calculations on $M$-changing collisions of NH ($^3\Sigma^-$) molecules in magnetically trappable states using a recently calculated potential energy surface. We show that elastic collision rates are much faster than inelastic rates for a wide range of fields at temperatures up to 10 mK and that the ratio increases for lower temperatures and magnetic fields. If NH molecules can be cooled to temperatures approaching 10 mK and brought into contact with laser-cooled Mg then there is a good prospect that sympathetic cooling can be achieved.