SciPost Submission Page

Long-distance entanglement in Motzkin and Fredkin spin chains

by Luca Dell'Anna

Submission summary

As Contributors: Luca Dell'Anna
Preprint link: scipost_201905_00002v2
Date accepted: 2019-10-04
Date submitted: 2019-09-23
Submitted by: Dell'Anna, Luca
Submitted to: SciPost Physics
Domain(s): Theoretical
Subject area: Quantum Physics

Abstract

We derive some entanglement properties of the ground states of two classes of quantum spin chains described by the Fredkin model, for half-integer spins, and the Motzkin model, for integer ones. Since the ground states of the two models are known analytically, we can calculate the entanglement entropy, the negativity and the quantum mutual information exactly. We show, in particular, that these systems exhibit long-distance entanglement, namely two disjoint regions of the chains remain entangled even when the separation is sent to infinity, i.e. these systems are not affected by decoherence. This strongly entangled behavior, occurring both for colorful versions of the models (with spin larger than 1/2 or 1, respectively) and for colorless cases (spin 1/2 and 1), is consistent with the violation of the cluster decomposition property. Moreover we show that this behavior involves disjoint segments located both at the edges and in the bulk of the chains.

Current status:
Publication decision taken: accept

Author comments upon resubmission

Dear Editor,
hereafter the new version of the paper with the changes made in accordance with the requests of the Referee.
The reply and the changes have been already sent in July.

List of changes

The list of changes has been sent already in the reply to the Referee's report in July.


Reports on this Submission

Anonymous Report 1 on 2019-10-1 Invited Report

Report

I think the manuscript is improved and I am satisfied with the author's changes and responses to my requested changes.
I now recommend publication, however I did find at least one typo that a standard spellcheck would have turned up (bottom of page 7, "Before to proceed ne need to know").

  • validity: high
  • significance: ok
  • originality: good
  • clarity: good
  • formatting: good
  • grammar: acceptable

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Comments

Anonymous on 2019-09-23
Category:
remark

The paper is the same as posted in arXiv with the version 1904.05205v3