Emergent Bloch oscillations in a kinetically constrained Rydberg spin lattice

TL;DR

This paper demonstrates that weak extended interactions in kinetically constrained Rydberg spin lattices can induce Bloch oscillations, significantly affecting relaxation dynamics and potentially leading to non-ergodic behavior.

Contribution

It reveals how weak beyond-nearest-neighbor interactions cause Bloch oscillations in Rydberg spin clusters, impacting relaxation and ergodicity in kinetically constrained systems.

Findings

Weak interactions induce Bloch oscillations.

Bloch oscillations hinder cluster expansion.

Experimental detection via Rydberg atom density.

Abstract

We explore the relaxation dynamics of elementary spin clusters of a kinetically constrained spin system. Inspired by experiments with Rydberg lattice gases, we focus on the situation in which an excited spin leads to a "facilitated" excitation of a neighboring spin. We show that even weak interactions that extend beyond nearest neighbors can have a dramatic impact on the relaxation behavior: they generate a linear potential, which under certain conditions leads to the onset of Bloch oscillations of spin clusters. These hinder the expansion of a cluster and more generally the relaxation of many-body states towards equilibrium. This shows that non-ergodic behavior in kinetically constrained systems may occur as a consequence of the interplay between reduced connectivity of many-body states and weak interparticle interactions. We furthermore show that the emergent Bloch oscillations identified here can be detected in experiment through measurements of the Rydberg atom density, and discuss how spin-orbit coupling between internal and external degrees of freedom of spin clusters can be used to control their relaxation behavior.