Observing Quasiparticles through the Entanglement Lens

TL;DR

This paper introduces a quantum information approach to analyze the entanglement structure of quantum states, revealing properties of quasiparticles such as quantum numbers and fractionalization through entanglement spectra and mutual information.

Contribution

It proposes a novel framework that links quasiparticle characteristics to entanglement features, extending traditional low-energy physics analysis.

Findings

Entanglement spectrum reflects quasiparticle quantum numbers.

Mutual information reveals fractionalization and locality.

Framework applied successfully to the 1D transverse field Ising model.

Abstract

The low energy physics of interacting quantum systems is typically understood through the identification of the relevant quasiparticles or low energy excitations and their quantum numbers. We present a quantum information framework that goes beyond this to examine the nature of the entanglement in the corresponding quantum states. We argue that the salient features of the quasiparticles, including their quantum numbers, locality and fractionalization are reflected in the entanglement spectrum and in the mutual information. We illustrate these ideas in the specific context of the $d=1$ transverse field Ising model with an integrability breaking perturbation.