Relaxation of the collective magnetization of a dense 3D array of interacting dipolar S=3 atoms

TL;DR

This study investigates the collective spin dynamics of a dense 3D lattice of S=3 chromium atoms with dipolar interactions, revealing unexpected coherence persistence and highlighting the importance of spin coherences in understanding many-body quantum systems.

Contribution

It provides the first detailed experimental analysis of collective magnetization dynamics in a dense S=3 atomic lattice, combining measurements with numerical simulations of the XXZ model.

Findings

Spin populations are unaffected by spin echo techniques.

Spin length decays slower than predicted by simulations.

A small nonzero asymptotic spin length is observed.

Abstract

We report on measurements of the dynamics of the collective spin length (total magnetization) and spin populations in an almost unit filled lattice system comprising about 10^4 spin S=3 chromium atoms, under the effect of dipolar interactions. The observed spin population dynamics is unaffected by the use of a spin echo, and fully consistent with numerical simulations of the S=3 XXZ spin model. On the contrary, the observed spin length decays slower than in simulations, and surprisingly reaches a small but nonzero asymptotic value within the longest timescale. Our findings show that spin coherences are sensitive probes to systematic effects affecting quantum many-body behavior that cannot be diagnosed by merely measuring spin populations.