Entanglement Hamiltonians for Periodic Free Fermion Chains with Defects

TL;DR

This paper investigates how defects in periodic free fermion chains affect the structure of entanglement Hamiltonians, revealing non-local couplings that decay with distance and depend on defect strength.

Contribution

It provides a detailed analysis of entanglement Hamiltonians in the presence of defects, highlighting the emergence of non-local terms and their dependence on defect parameters.

Findings

Defects induce non-local couplings in entanglement Hamiltonians.

Couplings across defects decay with distance.

Fitted non-local couplings vary with defect strength.

Abstract

We study the half system entanglement Hamiltonians of the ground state of free fermion critical transverse field Ising model with periodic boundary conditions in the presence of defects. In general, we observe that these defects introduce non-local terms into the entanglement Hamiltonian, with the most significant being couplings across the defect that decay with distance. We also perform a limited entanglement Hamiltonian reconstruction using an ansatz and analyze how the fitted non-local couplings vary with defect strength.