Observation of Magnetic Devil's Staircase-Like Behavior in Quasiperiodic Qubit Lattices

TL;DR

This study demonstrates that quasiperiodic qubit lattices exhibit magnetic devil's staircase behavior, with rich, scale-independent magnetization patterns driven by external fields, challenging the belief that such phenomena are exclusive to periodic systems.

Contribution

It reveals that aperiodic, quasiperiodic geometries can produce devil's staircase magnetic responses using short-range antiferromagnetic couplings, expanding understanding beyond traditional periodic systems.

Findings

Magnetic transitions occur between spin manifolds driven by external fields.

Quasiperiodic lattices produce rich, scale-independent magnetization patterns.

Devil's staircase behavior is observed in aperiodic geometries, not just periodic ones.

Abstract

The devil's staircase (DS) phenomenon is a fractal response of magnetization to external fields, traditionally observed in periodic ferromagnetic systems, where the commensurability between spin arrangements, lattice parameters, and external magnetic fields governs abrupt changes in magnetization. Its occurrence in aperiodic, fractal-type systems has remained largely unexplored, despite their natural compatibility with such phenomena. Using a quantum annealing device, we uncover a wealth of abrupt magnetic transitions between spin manifolds driven by increasing external magnetic fields within a simple yet effective Ising-model framework. In contrast to periodic systems, where DS arises from long-range competing interactions, our findings reveal that short-range, purely antiferromagnetic couplings in aperiodic geometries produce equally rich ground-state magnetization patterns. We demonstrate that while magnetic textures are determined by the lattice size, their formation remains remarkably robust and independent of scale, with commensurability emerging locally. Our results challenge the prevailing view that DS behavior is limited to periodic systems and establish quasiperiodic geometries as a natural host for this phenomenon.