The DSUB$m$ Approximation Scheme for the Coupled Cluster Method and Applications to Quantum Magnets

Abstract

A new approximate scheme, DSUB$m$, is described for the coupled cluster method. We then 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, quantum Monte Carlo methods and those from the CCM using the LSUB$m$ scheme.

18 pages, 10 figures

Cited by in corpus (2)

• The Coupled Cluster Method Applied to Quantum Magnets: A New LPSUB$m$ Approximation Scheme for Lattice Models
• Coupled-cluster calculations for the ground- and excited-states of the spin-half XXZ model