Observing weakly broken conservation laws in a dipolar Rydberg quantum spin chain
Abstract
Integrable quantum many-body systems host families of extensive conservation laws, some of which are fragile: even infinitesimal perturbations can qualitatively alter their dynamical constraints. Here we show that this fragility leaves a clear experimental fingerprint in a one-dimensional quantum spin chain of as few as 14 Rydberg atoms. Weak integrability breaking from interatomic dipolar couplings is directly detectable within experimentally accessible times in the dynamics of non-local observables. In particular, magnetization fluctuations are highly sensitive to the breaking of fragile conservation laws and exhibit anomalous growth, which we observe experimentally; similar signatures appear in a semilocal string observable. Numerical simulations on substantially longer chains and a simplified classical stochastic model reproduce those features. We establish non-local observables as a sensitive probe of fragile conservation laws in quantum spin chains and Rydberg-atom arrays as a platform to test perturbative descriptions of quantum many-body dynamics with weak integrability breaking.
Cite
@article{arxiv.2602.02251,
title = {Observing weakly broken conservation laws in a dipolar Rydberg quantum spin chain},
author = {Cheng Chen and Luca Capizzi and Alice Marché and Guillaume Bornet and Gabriel Emperauger and Thierry Lahaye and Antoine Browaeys and Maurizio Fagotti and Leonardo Mazza},
journal= {arXiv preprint arXiv:2602.02251},
year = {2026}
}
Comments
9 pages + References and Additional Materials; 8 Figures