Devil's staircases without particle-hole symmetry

TL;DR

This paper introduces spin models with long-range interactions that exhibit a devil's staircase in their ground states, notably lacking particle-hole symmetry, allowing independent control of particle and hole sectors, leading to novel hybrid staircases.

Contribution

The authors develop and analyze spin models with long-range interactions that display a devil's staircase without particle-hole symmetry, enabling separate control of particle and hole sectors.

Findings

Models exhibit a devil's staircase in ground states.

Absence of particle-hole symmetry leads to hybrid staircases.

Independent control of particle and hole sectors is possible.

Abstract

We present and analyze spin models with long-range interactions whose ground state features a so-called devil's staircase and where plateaus of the staircase are accessed by varying two-body interactions. This is in contrast to the canonical devil's staircase, for example occurring in the one-dimensional Ising model with long-range interactions, where typically a single-body chemical potential is varied to scan through the plateaus. These systems, moreover, typically feature a particle-hole symmetry which trivially connects the hole part of the staircase (filling fraction $f\geq1/2$) to its particle part ($f\leq1/2$). Such symmetry is absent in our models and hence the particle sector and the hole sector can be separately controlled, resulting in exotic hybrid staircases.