Parity order as a fundamental driver of bosonic topology

TL;DR

This paper demonstrates that parity order, when combined with bond dimerization, serves as a fundamental mechanism driving topological phases in interacting bosonic systems, expanding understanding beyond traditional symmetry reliance.

Contribution

It introduces parity order as a new organizing principle for bosonic topology, revealing two novel topological phases driven by parity coupling.

Findings

Identification of an SPT phase at half filling stabilized by positive parity coupling.

Discovery of a topological phase at unit filling stabilized by negative parity coupling.

Establishment of parity order as a fundamental driver of bosonic topological phases.

Abstract

Symmetry-protected topological (SPT) phases in interacting bosonic systems have been widely explored, yet most realizations rely on fine-tuned interactions or enlarged symmetries. Here we show that a qualitatively simpler mechanism--parity order coupled to bond dimerization--acts as a fundamental driver of bosonic topology. Using density matrix renormalization group simulations, we identify two distinct topological phases absent in the purely dimerized model: an SPT phase at half filling stabilized by positive parity coupling, and a topological phase at unit filling stabilized by negative coupling that can be adiabatically connected to a trivial phase without breaking any symmetry. Our results establish parity order as a new organizing principle for correlation-driven bosonic topology.