Semiclassical Eigenstates of Four-Sublattice Antiferromagnets

Two-dimensional Behavior of the Sublattice Magnetization in Three Dimensional Ising Antiferromagnets

A three-dimensional layered Ising-Antiferromagnet with a ferromagnetic intra-layer coupling to z neighbors, zJ > 0, and an antiferromagnetic interlayer coupling to z neighbors, zJ ′ < 0, is investigated by Monte Carlo simulations on a hexagonal lattice. The physical nature of the anomalous temperature bahavior of the sublattice magnetizations, which is found for certain values of r = zJ/zJ ′ an...

Vibrational Eigenstates of Four-Atom Molecules: A Parallel Strategy Employing the Implicitly Restarted Lanczos Method

We present an approach for determining the vibrational eigenstates of four-atom molecules. The primary representation of the (six-dimensional) eigenstates involves a nite basis or quantum number representation, whereas Hamiltonian matrix-vector products are evaluated with the aid of certain grid or discrete variable representations. This approach leads to computational and memory demands that a...

Accuracy of Approximate Eigenstates

Besides perturbation theory, which requires the knowledge of the exact unperturbed solution, variational techniques represent the main tool for any investigation of the eigenvalue problem of some semibounded operator H in quantum theory. For a reasonable choice of the employed trial subspace of the domain of H, the lowest eigenvalues of H can be located with acceptable precision whereas the tri...

4 Eigenvalues & eigenstates

Finite-temperature phase transition in a class of four-state Potts antiferromagnets.

We argue that the four-state Potts antiferromagnet has a finite-temperature phase transition on any Eulerian plane triangulation in which one sublattice consists of vertices of degree 4. We furthermore predict the universality class of this transition. We then present transfer-matrix and Monte Carlo data confirming these predictions for the cases of the Union Jack and bisected hexagonal lattices.