Preparation of an ultra-cold sample of ammonia molecules for precision measurements

TL;DR

This paper demonstrates a method to prepare ultra-cold ammonia molecules for precision measurements by using adiabatic cooling and re-compression, enabling extended free expansion times for high-resolution spectroscopy.

Contribution

It introduces a novel technique combining adiabatic cooling and re-compression to prolong the observation time of ultra-cold molecules for precision experiments.

Findings

Molecules observed after more than 10 ms of free expansion.

Statistical uncertainty decreases with the inverse square root of expansion time.

Potential for high-resolution spectroscopy and fundamental physics tests.

Abstract

We present experiments in which an ultra-cold sample of ammonia molecules is released from an electrostatic trap and recaptured after a variable time. It is shown that, by performing adiabatic cooling before releasing the molecules and adiabatic re-compression after they are recaptured, we are able to observe molecules even after more than 10 ms of free expansion. A coherent measurement performed during this time will have a statistical uncertainty that decreases approximately as the inverse of the square root of the expansion time. This offers interesting prospects for high-resolution spectroscopy and precision tests of fundamental physics theories.