# `St\"uckelberg interferometry' with ultracold molecules

## TL;DR

This paper demonstrates a St"uckelberg interferometer using ultracold molecules, enabling precise energy difference measurements and control over molecular state dynamics for potential applications in precision measurement.

## Contribution

It introduces a novel time-domain interferometer based on ultracold molecules' internal states, allowing high-precision energy measurements and control.

## Key findings

- High-contrast population oscillations observed
- Precise energy difference measurement achieved
- Demonstrated control over interferometer dynamics

## Abstract

We report on the realization of a time-domain `St\"uckelberg interferometer', which is based on the internal state structure of ultracold Feshbach molecules. Two subsequent passages through a weak avoided crossing between two different orbital angular momentum states in combination with a variable hold time lead to high-contrast population oscillations. This allows for a precise determination of the energy difference between the two molecular states. We demonstrate a high degree of control over the interferometer dynamics. The interferometric scheme provides new possibilities for precision measurements with ultracold molecules.