Title: The DSUBm approximation scheme for the coupled cluster method and applications to quantum magnets
Author(s):

	R.F. Bishop (School of Physics and Astronomy, Schuster Building, The University of Manchester, Manchester, M13 9PL, UK),
	P.H.Y. Li (School of Physics and Astronomy, Schuster Building, The University of Manchester, Manchester, M13 9PL, UK) ,
	J. Schulenburg (Universitätsrechenzentrum, Universität Magdeburg, P.O. Box 4120, 39016 Magdeburg, Germany)

A new approximate scheme, DSUBm, is described for the coupled cluster method. We apply it to two well-studied (spin-1/2 Heisenberg antiferromagnet) spin-lattice models, namely: the XXZ and the XY models on the square lattice in two dimensions. Results are obtained in each case for the ground-state energy, the sublattice magnetization and the quantum critical point. They are in good agreement with those from such alternative methods as spin-wave theory, series expansions, exact diagonalization techniques, quantum Monte Carlo methods and those from the CCM using the LSUBm scheme.

Key words: coupled cluster method, quantum antiferromagnet
PACS: 75.10.Jm, 75.30.Gw, 75.40.-s, 75.50.Ee
Comments: Figs. 6, Refs. 43, Tabs. 3

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