Extractable entanglement from a Euclidean hourglass

TL;DR

This paper extends a Euclidean hourglass method to compute extractable entanglement entropy for spherical surfaces in conformal field theories, demonstrating its effectiveness across various models.

Contribution

It generalizes the hourglass prescription to spherical entangling surfaces and validates it through multiple quantum field theory examples.

Findings

Successfully evaluated log terms in entropy for different models.

Reproduced known results for Maxwell field entropy.

Supports the hourglass method as a Euclidean approach for extractable entropy.

Abstract

We previously proposed that entanglement across a planar surface can be obtained from the partition function on a Euclidean hourglass geometry. Here we extend the prescription to spherical entangling surfaces in conformal field theory. We use the prescription to evaluate log terms in the entropy of a CFT in two dimensions, a conformally-coupled scalar in four dimensions, and a Maxwell field in four dimensions. For Maxwell we reproduce the extractable entropy obtained by Soni and Trivedi. We take this as evidence that the hourglass prescription provides a Euclidean technique for evaluating extractable entropy in quantum field theory.