Mutual information on the fuzzy sphere

TL;DR

This study compares entanglement entropy and mutual information in free scalar fields on commutative and noncommutative spheres, revealing differences in UV divergence behavior but similar large-distance correlations.

Contribution

It provides the first numerical comparison of entanglement properties between commutative and fuzzy spheres, highlighting the impact of nonlocality on UV divergences.

Findings

Entanglement entropy on fuzzy sphere does not follow an area law.

Mutual information is identical in both theories despite UV divergence differences.

Nonlocality does not affect large-distance quantum correlations.

Abstract

We numerically calculate entanglement entropy and mutual information for a massive free scalar field on commutative (ordinary) and noncommutative (fuzzy) spheres. We regularize the theory on the commutative geometry by discretizing the polar coordinate, whereas the theory on the noncommutative geometry naturally posseses a finite and adjustable number of degrees of freedom. Our results show that the UV-divergent part of the entanglement entropy on a fuzzy sphere does not follow an area law, while the entanglement entropy on a commutative sphere does. Nonetheless, we find that mutual information (which is UV-finite) is the same in both theories. This suggests that nonlocality at short distances does not affect quantum correlations over large distances in a free field theory.