English

$\mathbb{Z}_N$ symmetry breaking in Projected Entangled Pair State models

Statistical Mechanics 2017-08-15 v1 Quantum Physics

Abstract

We consider Projected Entangled Pair State (PEPS) models with a global ZN\mathbb Z_N symmetry, which are constructed from ZN\mathbb Z_N-symmetric tensors and are thus ZN\mathbb Z_N-invariant wavefunctions, and study the occurence of long-range order and symmetry breaking in these systems. First, we show that long-range order in those models is accompanied by a degeneracy in the so-called transfer operator of the system. We subsequently use this degeneracy to determine the nature of the symmetry broken states, i.e., those stable under arbitrary perturbations, and provide a succinct characterization in terms of the fixed points of the transfer operator (i.e.\ the different boundary conditions) in the individual symmetry sectors. We verify our findings numerically through the study of a Z3\mathbb Z_3-symmetric model, and show that the entanglement Hamiltonian derived from the symmetry broken states is quasi-local (unlike the one derived from the symmetric state), reinforcing the locality of the entanglement Hamiltonian for gapped phases.

Keywords

Cite

@article{arxiv.1703.04137,
  title  = {$\mathbb{Z}_N$ symmetry breaking in Projected Entangled Pair State models},
  author = {Manuel Rispler and Kasper Duivenvoorden and Norbert Schuch},
  journal= {arXiv preprint arXiv:1703.04137},
  year   = {2017}
}

Comments

11 pages

R2 v1 2026-06-22T18:43:31.357Z