Schwinger-boson approach to quantum spin systems: Gaussian fluctuactions in the "natural" gauge

Preprint

6 October 1997

preprint
Published by arXiv in arXiv

https://doi.org/10.48550/arXiv.cond-mat/9611097

Abstract

We compute the Gaussian-fluctuation corrections to the saddle-point Schwinger-boson results using collective coordinate methods. Concrete application to investigate the frustrated J1-J2 antiferromagnet on the square lattice shows that, unlike the saddle-point predictions, there is a quantum nonmagnetic phase for 0.53 < J2/J1 < 0.64. This result is obtained by considering the corrections to the spin stiffness on large lattices and extrapolating to the thermodynamic limit, which avoids the infinite-lattice infrared divergencies associated to Bose condensation. The very good agreement of our results with exact numerical values on finite clusters lends support to the calculational scheme employed.

Keywords

All Related Versions

Version 1, 1996-11-12, ArXiv
Version 2, 1997-10-06, ArXiv
Published version: Physical Review Letters, 78 (11), 2216.

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