Phys. Rev. Lett. 86, 528–531 (2001)High-Energy Magnon Dispersion and Multimagnon Continuum in the Two-Dimensional Heisenberg AntiferromagnetReceived 1 June 2000; published in the issue dated 15 January 2001 We use quantum Monte Carlo simulations and numerical analytic continuation to study high-energy spin excitations in the two-dimensional S = 1/2 Heisenberg antiferromagnet at low temperature. We present results for both the transverse (x) and longitudinal (z) dynamic spin structure factors Sx,z(q,ω) at q = (π,0) and (π/2,π/2). Linear spin-wave theory predicts no dispersion on the line connecting these momenta. Our calculations show that in fact the magnon energy at (π,0) is 10% lower than at (π/2,π/2). We also discuss the transverse and longitudinal multimagnon continua and their relevance to neutron scattering experiments. © 2001 The American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevLett.86.528
DOI:
10.1103/PhysRevLett.86.528
PACS:
75.40.Gb, 75.10.Jm, 75.40.Mg, 75.30.Ds
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