Entanglement entropy in Loop Quantum Gravity and geometrical area law

Muxin Han

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arXiv · 2510.26922

Entanglement entropy in Loop Quantum Gravity and geometrical area law

Muxin Han

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Abstract

The non-factorizing nature of the Hilbert space in Loop Quantum Gravity (LQG) due to gauge invariance requires a generalized definition of entanglement entropy. This work employs the framework of von Neumann algebras to investigate the entanglement entropy in LQG. On a graph, the holonomy and flux operators within a region and on the boundary generate a non-factor type I von Neumann algebra, which is used to define the entanglement entropy for LQG states. This algebraic formalism is applied to ``fixed-area states''--superpositions of spin networks associated with a surface with a definite macroscopic area given by the LQG area spectrum. By maximizing the entropy, we derive a geometrical area law where the entanglement entropy is proportional to the area. In addition, we show that bulk entanglement can renormalize the area-law coefficient and produce logarithmic corrections. The results in this paper closely relate to LQG black hole entropy.

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Muxin Han. 2025-10-30. Entanglement entropy in Loop Quantum Gravity and geometrical area law. https://arxiv.org/abs/2510.26922

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