Thermalization within a Stark manifold through Rydberg atom interactions

TL;DR

This study investigates the thermalization process of ultracold Rb atoms in a Stark manifold, revealing partial thermalization influenced by density and long-range dipole interactions.

Contribution

It applies dynamical typicality to predict thermal states in a Stark manifold and compares these predictions with experimental equilibration data.

Findings

Atoms generally fail to thermalize at lower densities.

Approach to thermal state increases with density.

Thermalization is influenced by long-range dipole-dipole interactions.

Abstract

One explanation of the thermalization of an isolated quantum system is the eigenstate thermalization hypothesis, which posits that all energy eigenstates are thermal. Based on this idea, we use dynamical typicality to predict the thermal state of ultracold Rb atoms exchanging energy via long-range dipole-dipole interactions. In a magneto-optical trap, we excite the atoms to the center of a manifold of nearly harmonically spaced clusters of Stark energy levels and then allow them to equilibrate. Comparing the equilibrium state to our thermal prediction across a range of densities, we find that the atoms generally fail to thermalize, though they approach the thermal state at the highest tested density.