Extending rotational coherence of interacting polar molecules in a spin-decoupled magic trap

TL;DR

This paper demonstrates a significant extension of rotational coherence times in polar molecules by employing spin-decoupled magic trapping, reducing light shifts, and analyzing dipolar interaction effects in a dilute gas.

Contribution

It introduces a novel spin-decoupled magic trapping technique that nearly doubles the rotational coherence time in polar molecules.

Findings

Rotational coherence time extended to 8.7 ms

Spin-decoupled magic trapping reduces light shifts

Dipolar interactions cause density-dependent coherence times

Abstract

Superpositions of rotational states in polar molecules induce strong, long-range dipolar interactions. Here we extend the rotational coherence by nearly one order of magnitude to 8.7(6) ms in a dilute gas of polar $^{23}$Na$^{40}$K molecules in an optical trap. We demonstrate spin-decoupled magic trapping, which cancels first-order and reduces second-order differential light shifts. The latter is achieved with a dc electric field that decouples nuclear spin, rotation and trapping light field. We observe density-dependent coherence times, which can be explained by dipolar interactions in the bulk gas.