Localization and criticality in antiblockaded 2D Rydberg atom arrays

TL;DR

This paper investigates how positional disorder affects 2D Rydberg atom arrays under facilitation conditions, revealing a critical regime linked to a flat band, with implications for quantum matter studies.

Contribution

It uncovers a novel critical regime in 2D Rydberg arrays caused by a flat band, absent in 1D systems, and proposes experimental methods to explore these regimes.

Findings

Identification of a critical regime dependent on a flat band.

Discovery of a disorder-induced flat band in 2D Rydberg arrays.

Proposal of quench dynamics as an experimental probe.

Abstract

Controllable Rydberg atom arrays have provided new insights into fundamental properties of quantum matter both in and out of equilibrium. In this work, we study the effect of experimentally relevant positional disorder on Rydberg atoms trapped in a 2D square lattice under anti-blockade (facilitation) conditions. We show that the facilitation conditions lead the connectivity graph of a particular subspace of the full Hilbert space to form a 2D Lieb lattice, which features a singular flat band. Remarkably, we find three distinct regimes as the disorder strength is varied: a critical regime, a delocalized but nonergodic regime, and a regime with a disorder-induced flat band. The critical regime's existence depends crucially upon the singular flat band in our model, and is absent in any 1D array or ladder system. We propose to use quench dynamics to probe the three different regimes experimentally.