Exact results for the entanglement across defects in critical chains

TL;DR

This paper derives exact analytical formulas for entanglement entropy across defects in critical quantum chains, providing insights into how defects influence quantum correlations in fermionic and bosonic systems.

Contribution

It introduces new analytical expressions for entanglement spectra and entropy in quantum chains with defects, including both fermionic and bosonic cases.

Findings

Analytical formulas for the leading logarithmic coefficient of entanglement entropy.

Numerical results supporting the analytical findings for bosonic chains.

Comparison of entanglement spectra across different defect types.

Abstract

We consider fermionic and bosonic quantum chains where a defect separates two subsystems and compare the corresponding entanglement spectra. With these, we calculate their R\'enyi entanglement entropies and obtain analytical formulae for the continuously varying coefficient of the leading logarithmic term. For the bosonic case we also present numerical results.