1992/10/31 by S. Randjbar‐Daemi, S. Randjbar--Daemi, Abdus Salam +1 · 1 citation
Chemistry · Materials Science · Physics and Astronomy · #Advanced NMR Techniques and Applications #Magnetism in coordination complexes #Physics of Superconductivity and Magnetism #cond-mat #hep-th
paper · pdf · doi:10.1103/physrevb.48.3190
published as Phys.Rev.B48:3190-3205,1993 · 35, plain, IC/92/294
arxiv created 1992/11/03 · openalex publication_date 1993/08/01 · arxiv updated 2010/11/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
A generalization of the SU(2) spin systems on a lattice and their continuum limit to an arbitrary compact group G is discussed. The continuum limits are, in general, nonrelativistic \ensuremathσ-model-type field theories targeted on a homogeneous space G/H, where H contains the maximal torus of G. In the ferromagnetic case the equations of motion derived from our continuum Lagrangian generalize the Landau-Lifshitz equations with quadratic dispersion relation for small wave vectors. In the antiferromagnetic case the dispersion law is always linear in the long-wavelength limit. The models become relativistic only when G/H is a symmetric space. Also discussed are a generalization of the Holstein-Primakoff representation of the SU(N) algebra, the topological term, and the existence of the instanton-type solutions in the continuum limit of the antiferromagnetic systems.