AHB1, program description

SSE quantum Monte Carlo simulation of an isotropic S=1/2 Heisenberg model on a simple cubic lattice in 1, 2, or 3 dimensions. An efficient operator-loop update is used. The physical quantities calculated are: the internal energy, the specific heat, the uniform magnetic susceptibility, the spin stiffness, the staggered spin structure factor, and the staggered spin susceptibility.

Fortran program files

Complete simulation program
ahb1.f

Include-file for 'ahb1.f'
ahb1.h

Program for processing the output of 'ahb1.f'
ahb1res.f

Summary of usage

The full source code of the simulation program is in 'ahb1.f'. The program is compiled for a user-fixed dimensionality and lattice size, which are both set in the include-file 'ahb1.h'. The raw data generated by the simulation program AHB1 should be processed by the program AHB1RES (file 'ahb1res.f'), which calculates averages and statistical errors.

Details on how to run the program

Useful references for algorithms used

A. W. Sandvik, Phys. Rev. B 59, R14157 (1999) [Introduces the SSE operator-loop update].

A. W. Sandvik, Phys. Rev. B 56, 11678 (1997) [Discusses estimators for expectation values].

O. F. Syljućsen and A. W. Sandvik, cond-mat/0202316 (to appear in Phys. Rev. E) [Contains a detailed pedagogical discussion of the SSE algorithm].

Credits

Author: A. W. Sandvik
Cite references: A. W. Sandvik, Phys. Rev. B59, R14157 (1999)