Non-Gaussianity of Entanglement Entropy and Correlations of Composite Operators

TL;DR

This paper extends previous work on entanglement entropy in interacting field theories, revealing non-Gaussian contributions from interaction vertices as renormalized correlators of composite operators, enhancing understanding of EE's structure.

Contribution

It introduces a novel interpretation of non-Gaussian contributions to EE as renormalized composite operator correlations in general field theories.

Findings

Non-Gaussian contributions are interpreted as renormalized composite operator correlators.

The method applies to more general interacting field theories.

EE contributions include both two-point functions and interaction vertices.

Abstract

This is an extended version of the previous paper arXiv:2103.05303 to study entanglement entropy (EE) of a half space in interacting field theories. In the previous paper, we have proposed a novel method to calculate EE based on the notion of $\mathbb{Z}_M$ gauge theory on Feynman diagrams, and shown that EE consists of two particular contributions, one from a renormalized two-point correlation function in the two-particle irreducible (2PI) formalism and another from interaction vertices. In this paper, we further investigate them in more general field theories and show that the non-Gaussian contributions from vertices can be interpreted as renormalized correlation functions of composite operators.