Energy Transport Among Highly-Polarized Atoms

TL;DR

This study investigates energy transport among ultracold Rydberg atoms under a static electric field, revealing non-thermalization behavior and modeling it with a simplified computational approach.

Contribution

It demonstrates how energy exchange occurs in Rydberg atoms near a harmonic manifold and shows the system's failure to thermalize over time.

Findings

Energy spreads away from the center of the manifold.

System fails to thermalize for long interaction times.

A simplified model qualitatively matches experimental results.

Abstract

A static electric field of a few V/cm shifts the energy levels of ultracold Rydberg atoms in a magneto-optical trap. For a given principle quantum number, most of the energy levels are nearly degenerate at zero field and fan out with increasing field to form a manifold. We excite Rydberg atoms to energy levels near the center of the manifold, where the spacing is nearly harmonic, and allow them to exchange energy via resonant dipole-dipole interactions. We measure the time evolution as energy spreads away from the center of the manifold, which reveals that the system fails to thermalize for long interaction times. A computational model that includes only a few essential features of the system qualitatively agrees with this result.