Long-range entanglement and topological excitations

TL;DR

This paper demonstrates that Disconnected Entanglement Entropy can detect long-range entanglement in fractionalized excitations, revealing a phase with topological features resilient to disorder and quenches.

Contribution

It introduces a novel application of Disconnected Entanglement Entropy to identify long-range entanglement in single excitations and characterizes a new topological-like phase.

Findings

Disconnected Entanglement Entropy detects LRE in fractionalized excitations.

LRE persists under quantum quenches and disorder.

A phase with topological features exists outside traditional topological order.

Abstract

Topological order comes in different forms, and its classification and detection is an important field of modern research. In this work, we show that the Disconnected Entanglement Entropy, a measure originally introduced to identify topological phases, is also able to unveil the long-range entanglement (LRE) carried by a single, fractionalized excitation. We show this by considering a quantum, delocalized domain wall excitation that can be introduced into a system by inducing topological frustration in an antiferromagnetic spin chain. Furthermore, we study the resilience of LRE against a quantum quench and the introduction of disorder, thus establishing the existence of a phase with topological features despite not being a typical topological order or symmetry-protected one.