# Matter-wave interferometry with atoms in high Rydberg states

## TL;DR

This paper demonstrates matter-wave interferometry with helium atoms in high Rydberg states, showing quantum interference effects and potential applications in precision measurements of gravitational acceleration on exotic atoms.

## Contribution

It introduces a novel method of creating and observing matter-wave interference with high Rydberg states, expanding the scope of quantum interferometry with giant atomic states.

## Key findings

- Successful observation of matter-wave interference with Rydberg atoms.
- Quantitative agreement between experimental results and theoretical calculations.
- Potential for measuring gravitational effects on Rydberg positronium or antihydrogen.

## Abstract

Matter-wave interferometry has been performed with helium atoms in high Rydberg states. In the experiments the atoms were prepared in coherent superpositions of Rydberg states with different electric dipole moments. Upon the application of an inhomogeneous electric field, the different forces on these internal state components resulted in the generation of coherent superpositions of momentum states. Using a sequence of microwave and electric field gradient pulses the internal Rydberg states were entangled with the momentum states associated with the external motion of these matter waves. Under these conditions matter-wave interference was observed by monitoring the populations of the Rydberg states as the magnitudes and durations of the pulsed electric field gradients were adjusted. The results of the experiments have been compared to, and are in excellent quantitative agreement with, matter-wave interference patterns calculated for the corresponding pulse sequences. For the Rydberg states used, the spatial extent of the Rydberg electron wavefunction was ~320 nm. Matter-wave interferometry with such giant atoms is of interest in the exploration of the boundary between quantum and classical mechanics. The results presented also open new possibilities for measurements of the acceleration of Rydberg positronium or antihydrogen atoms in the Earth's gravitational field.