Universal entanglement signatures of interface conformal field theories

TL;DR

This paper investigates the entanglement properties of interface conformal field theories, revealing universal features such as the shared logarithmic scaling of mutual information and reflected entropy, linked to the smaller central charge.

Contribution

It demonstrates that entanglement measures can serve as universal probes for critical interface theories, highlighting their potential to uncover underlying physics.

Findings

Mutual information and reflected entropy share the same leading logarithmic scaling.

The effective interface central charge equals the smaller of the two CFT central charges.

Entanglement measures reveal universal features of critical interface theories.

Abstract

An interface connecting two distinct conformal field theories hosts rich critical behaviors. In this work, we investigate the entanglement properties of such critical interface theories for probing the underlying universality. As inspired by holographic perspectives, we demonstrate vital features of various entanglement measures regarding such interfaces based on several paradigmatic lattice models. Crucially, for two subsystems adjacent at the interface, the mutual information and the reflected entropy exhibit identical leading logarithmic scaling, giving an effective interface central charge that takes the same value as the smaller central charge of the two conformal field theories. Our work demonstrates that the entanglement measure offers a powerful tool to explore the rich physics in critical interface theories.