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arXiv · 2610.42127

Resolving the spinon hierarchy of the Heisenberg antiferromagnet

Ian P. McCulloch·Jesse J. Osborne
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Abstract

A local spin fluctuation in the spin-$\tfrac12$ Heisenberg antiferromagnet creates an even number of fractional spinon excitations. We resolve its zero-temperature dynamical structure factor through six spinons directly in the thermodynamic limit. Beyond the established two-spinon contribution of $72.89\%$, the four-spinon response gives approximately $21.90\%$ of the integrated intensity and six spinons contribute a further $4.3\%$, bringing the response to about $99\%$ of both the intensity and first-frequency-moment sum rules. We derive momentum-independent first-moment fractions in the calculated sectors and a general upper-edge law $S_n\sim A_n(k)(ω_{n,u}-ω)^{(n^2-3)/2}$ for every even $n$ at nonzero momentum. The rapid growth of the edge exponent explains why the expanding multiparticle bandwidth carries very little high-energy weight, while higher sectors remain appreciable within the lower-sector continua.

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Ian P. McCulloch, Jesse J. Osborne. 2026-10-30. Resolving the spinon hierarchy of the Heisenberg antiferromagnet. https://arxiv.org/abs/2610.42127

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