Entanglement Spectra of Heisenberg Ladders of higher Spin

TL;DR

This paper investigates the entanglement spectra of Heisenberg spin ladders with arbitrary spin, revealing proportionality to single-chain energy spectra in isotropic cases and complex behaviors in anisotropic higher-spin ladders.

Contribution

It provides a perturbative analysis of entanglement spectra for higher-spin Heisenberg ladders, highlighting differences between isotropic and anisotropic cases and extending understanding to dimerized chains.

Findings

Entanglement spectrum proportional to single-chain energy spectrum in isotropic ladders.

Anisotropic higher-spin ladders exhibit nontrivial entanglement spectra.

Discussion of entanglement in dimerized spin chains.

Abstract

We study the entanglement spectrum of Heisenberg spin ladders of arbitrary spin length S in the perturbative regime of strong rung coupling. For isotropic spin coupling the the entanglement spectrum is, within first order perturbation theory, always proportional to the energy spectrum of the single chain with a proportionality factor being also independent of S. A more complicated situation arises for anisotropic ladders of higher spin S>=1 since here even the unperturbed ground state has a nontrivial entanglement spectrum. Finally we discuss related issues in dimerized spin chains.