Intersublattice entanglement entropy as an extensive property in antiferromagnets

Recent advancements in our understanding of ordered magnets call for a quantification their entanglement content on an equal footing with classical thermodynamic quantities, such as the total magnetic moment. We evaluate entropy (EE) between two sublattices bipartite antiferromagnet, finding it to scale volume. Thus, EE density becomes intensive property and is evaluated be universal dimensionality-dependent constant when exchange dominant interaction. Our analytic results are validated against DMRG-based analysis one-dimensional (1D) system, good agreement. Furthermore, per bond provides useful shortcut towards obtaining central-cut 1D, area law higher-dimensional magnets.