On entanglement entropy in 't Hooft model

TL;DR

This paper calculates the entanglement entropy in the 't Hooft model using the replica trick, revealing that mesons contribute as point-like particles to the entanglement c-function in the large-N limit.

Contribution

It demonstrates that the entanglement c-function in the 't Hooft model can be expressed as a sum of free massive scalar contributions, each representing a meson, with a detailed explanation of this phenomenon.

Findings

Entanglement c-function equals a sum of free scalar c-functions.

Each meson contributes as a point-like particle.

Explicit calculation in the large-N limit.

Abstract

We use the replica trick approach to calculate, in the large-N limit, the entanglement c-function in two-dimensional quantum chromodynamics with the gauge group U(N) and quark in the fundamental representation ('t Hooft model). We show explicitly that the result is equal to a sum (with certain numerical coefficients) of entanglement c-functions of free massive scalars, which represent mesons in spectrum of the 't Hooft model. Interestingly, each meson contributes as a point-like particle. We provide an explanation for why this is the case.