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Journal of the Physical Society of Japan

Order Parameter in Quantum Antiferromagnets

T. A. Kaplan, Peter Horsch, Wolfgang von der Linden

Published Nov 15, 1989• 52 citations
Publisher

Abstract

We discuss the nature of symmetry breaking in quantum antiferromagnets. We show that published arguments concerning the order parameter for the 2d s =1/2 Heisenberg antiferromagnet have to be reconsidered. These had led to \(\sqrt{3}\) and 1 for the ratio r of the mean z -component m of the staggered spin per particle m s z in an infinitesimal staggered field B , to the r.m.s. value m 0 of m s z with B =0, in the thermodynamic limit. We give arguments which put doubt on both values. Also we prove r ≧1, given m 0 ≠0.

DOI
10.1143/jpsj.58.3894

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