Pair localization in dipolar systems with tunable positional disorder

TL;DR

This paper investigates how tunable positional disorder in dipolar systems affects localization phenomena, revealing a crossover to localized states and identifying strongly interacting pairs as key conserved entities.

Contribution

It introduces a model of disorder through random spin-spin couplings in a dipolar Heisenberg XXZ system, highlighting localization effects driven by interaction disorder.

Findings

System exhibits a localization crossover.

Strongly interacting pairs act as local conserved quantities.

Entanglement entropy supports localization transition.

Abstract

Strongly interacting quantum systems subject to quenched disorder exhibit intriguing phenomena such as glassiness and many-body localization. Theoretical studies have mainly focused on disorder in the form of random potentials, while many experimental realizations naturally feature disorder in the interparticle interactions. Inspired by cold Rydberg gases, where such disorder can be engineered using the dipole blockade effect,we study a Heisenberg XXZ spin model where the disorder is exclusively due to random spin-spin couplings, arising from power-law interactions between randomly positioned spins. Using established spectral and eigenstate properties and entanglement entropy, we show that this system exhibits a localization crossover and identify strongly interacting pairs as emergent local conserved quantities in the system, leading to an intuitive physical picture consistent with our numerical results.