Numerical solution for the ground-state energy of the anisotropic Heisenberg model

Author(s):  
P. Bracken
1995 ◽  
Vol 09 (10) ◽  
pp. 619-627 ◽  
Author(s):  
R. A. SAUERWEIN ◽  
M. J. DE OLIVEIRA

The spin-1/2 antiferromagnetic Heisenberg model with spatial anisotropy is studied on a cubic lattice by a Monte Carlo Method. Two types of spatial anisotropies are considered: planar and axial. The staggered magnetization m† and the ground state energy per site ∊0 are obtained as a function of the anisotropy. In the isotropic case we have obtained m† = 0.429 ± 0.001 in units where the saturated value is 0.5 and ∊0 = –0.899 ± 0.001.


1989 ◽  
Vol 03 (09) ◽  
pp. 1443-1446 ◽  
Author(s):  
C.Y. PAN

The ground-state energy of the spin-1/2 two-dimensional antiferromagnetic Heisenberg model is obtained by a real space renormalization group method. A relative larger cluster (5×5) is used to improve the accuracy and a boundary theory is applied to extrapolate to the result which is in good agreement with the finite-size calculation and in fairly good agreement with the other available numerical estimates. How to further improve the calculation is discussed.


1994 ◽  
Vol 47 (2) ◽  
pp. 137 ◽  
Author(s):  
Lloyd CL Hollenberg ◽  
Michael J Tomlinson

In the presence of a staggered magnetic field, the plaquette expansion of the Lanczos matrix elements are obtained for the antiferromagnetic 2D Heisenberg model up to order 1/Np (Np is the number of plaquettes on the lattice). The resulting approximate tri-diagonal form of the Hamiltonian is diagonalised for various values of the field strength in the -> 00 limit for the ground state energy density. From the behaviour of the ground-state energy density at weak fields, the staggered magnetisation at this order in the plaquette expansion is found to be 0�71 (in units where the Neel state staggered magnetisation is 1� 0).


1994 ◽  
Vol 4 (9) ◽  
pp. 1281-1285 ◽  
Author(s):  
P. Sutton ◽  
D. L. Hunter ◽  
N. Jan

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