Abstract:
We investigate low-temperature magnetization processes for two frustrated quantum Heisenberg antiferromagnets using the lattice gas model. The emerging discrete degrees of freedom indicate a close relation of the frustrated quantum Heisenberg antiferromagnet to the classical lattice gas with a finite nearest-neighbor repulsion or, equivalently, to the Ising antiferromagnet in a uniform magnetic field. Using this relation, we obtain analytic results for thermodynamically large systems in the one-dimensional case. In the two-dimensional case, we simulate systems of the size up to $100\times100$ sites using the classical Monte Carlo method.