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Nonlinear σ model treatment of quantum antiferromagnets in a magnetic field
Author(s) -
Normand B.,
Kyriakidis Jordan,
Loss Daniel
Publication year - 2000
Publication title -
annalen der physik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.009
H-Index - 68
eISSN - 1521-3889
pISSN - 0003-3804
DOI - 10.1002/(sici)1521-3889(200002)9:2<133::aid-andp133>3.0.co;2-z
Subject(s) - physics , sigma model , magnetization , renormalization group , quantum , spin (aerodynamics) , condensed matter physics , magnetic field , nonlinear system , critical exponent , symmetry (geometry) , quantum mechanics , density matrix renormalization group , quantum electrodynamics , phase transition , geometry , mathematics , thermodynamics
We present a theoretical analysis of the properties of low‐dimensional quantum antiferromagnets in applied magnetic fields. In a nonlinear σ model description, we use a spin stiffness analysis, a 1/N expansion, and a renormalization group approach to describe the broken‐symmetry regimes of finite magnetization, and, in cases of most interest, a low‐field regime where symmetry is restored by quantum fluctuations. We compute the magnetization, critical fields, spin correlation functions, and decay exponents accessible by nuclear magnetic resonance experiments. The model is relevant to many systems exhibiting Haldane physics, and provides good agreement with data for the two‐chain spin ladder compound CuHpCl.