Scalable Spin Squeezing in Power-Law Interacting XXZ Models with Disorder

TL;DR

This paper investigates the robustness of spin squeezing in two-dimensional power-law interacting XXZ models with disorder, demonstrating conditions under which scalable squeezing is achievable despite positional imperfections.

Contribution

It introduces a phase diagram for scalable spin squeezing in disordered power-law systems and explains the limitations observed in NV center experiments.

Findings

Scalable spin squeezing exists below a certain disorder threshold.

Disorder significantly impacts the scalability of squeezing.

Controlled defect creation can enhance scalable squeezing in solid-state systems.

Abstract

While spin squeezing has been traditionally considered in all-to-all interacting models, recent works have shown that it can also occur in systems with power-law interactions, enabling direct tests in Rydberg atoms, trapped ions, ultracold atoms, and nitrogen-vacancy (NV) centers in diamond. For the latter, Wu et al. Nature 646 (2025) demonstrated that spin squeezing is heavily affected by positional disorder, reducing any capacity for a practical squeezing advantage, which requires scalability with the system size. In this Letter we explore the robustness of spin squeezing in two-dimensional lattices with a fraction of unoccupied lattice sites. Using semiclassical modeling, we demonstrate the existence of scalable squeezing in power-law interacting XXZ models up to a disorder threshold, above which squeezing is not scalable. We produce a phase diagram for scalable squeezing, and explain its absence in the aforementioned NV experiment. Our work illustrates the maximum disorder allowed for realizing scalable spin squeezing in a host of quantum simulators, highlights a regime with substantial tolerance to disorder, and identifies controlled defect creation as a promising route for scalable squeezing in solid-state systems.