Spin-wave interactions in quantum antiferromagnetsN. Hasselmann and P. Kopietz
Institut für Theoretische Physik, Universität Frankfurt - Max-von-Laue Strasse 1 D-60438 Frankfurt, Germany
received 30 January 2006; accepted in final form 25 April 2006
published online 17 May 2006
We study spin-wave interactions in quantum antiferromagnets by expressing the usual magnon annihilation and creation operators in terms of Hermitian field operators representing transverse staggered and ferromagnetic spin fluctuations. In this parameterization, which was anticipated by Anderson in 1952, the two-body interaction vertex between staggered spin fluctuations vanishes at long wavelengths. We derive a new effective action for the staggered fluctuations only by tracing out the ferromagnetic fluctuations. To one loop order, the renormalization group flow agrees with the nonlinear--model approach.
75.10.Jm - Quantized spin models.
75.30.Ds - Spin waves.
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