Harris, A. Brooks2023-05-232023-05-231991-04-152015-07-09https://repository.upenn.edu/handle/20.500.14332/43155The commensurability energy ΔE is calculated for a Heisenberg helimagnet whose wavelength is three lattice constants at zero temperature with a small but nonzero uniform field applied in the plane of polarization of the spins. It is shown that ΔE=0 for classical spins but ΔE≠0 for quantum spins when spin‐wave interactions are considered.Reprinted with permission from the Journal of Applied Physics. Copyright 1991, American Institute of Physics.PhysicsQuantum PhysicsArticle