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We have studied two models for anisotropic quantum spin chains. (i) XY‐chain with a field in the plane: The magnetization of the ferromagnet behaves as h1/3 for small fields, in agreement with scaling laws. The antiferromagnet shows a critical field at which the ground state is a simple Néel state and which separates power law from exponential decay of spatial correlations. (ii) Anisotropic XY‐chain: The dynamic z‐component spin correlation function can be decomposed into a spin wave and a soliton contribution. The nature of quantum soliton excitations is studied and their form compared to soliton solutions of classical equations of motion.
J. Kurmann, Gerhard Müller, H. Thomas, M. W. Puga and Beck, H. Anisotropic quantum spin chains. J. Appl. Phys. 52 (1981), 1968-1970.
Available at: http://dx.doi.org/10.1063/1.329586