Phase diagram of a dual-species Rydberg atom ladder

TL;DR

This paper maps the complex phase diagram of a dual-species Rydberg atom ladder, revealing novel ordered, disordered, and crossover phenomena enabled by competing interactions and quantum fluctuations.

Contribution

It provides the first large-scale DMRG analysis of dual-species Rydberg arrays, identifying multiple symmetry-breaking phases and a multi-critical point.

Findings

Identified disordered, ordered, and floating phases with incommensurate correlations.

Discovered a smooth crossover between different $ ext{Z}_2$-ordered regimes.

Located a multi-critical point where multiple phase transition lines intersect.

Abstract

Dual-species Rydberg atom arrays extend single-species platforms by introducing competing interaction scales and enhanced quantum fluctuations, enabling phenomena beyond homogeneous settings. In this work, we study the ground-state phase diagram of a one-dimensional dual-species Rydberg atom ladder using large-scale density-matrix renormalization group calculations. We identify disordered phases, multiple ordered phases with $\mathbb{Z}_2$, $\mathbb{Z}_3$, and $\mathbb{Z}_4$ symmetry, as well as floating phases characterized by incommensurate wave vectors and algebraically decaying correlations. Importantly, we observe a smooth crossover between distinct $\mathbb{Z}_2$-ordered regimes, reflecting a reorganization of low-energy degrees of freedom rather than a true phase transition, which is absent in single-species Rydberg arrays. We further uncover a multi-critical point at the boundary between the $\mathbb{Z}_2 \otimes \mathbb{Z}_2$ and $\mathbb{Z}_3 \otimes \mathbb{Z}_3$ ordered phases, where Ising, chiral, and first-order transition lines intersect. Our results demonstrate that dual-species Rydberg atom arrays provide a unique platform for realizing crossover physics and multi-critical behavior inaccessible in single-species architectures.