The magnetocaloric effect is studied at the transition to saturation in the antiferromagnetic spin-1/2 Heisenberg model on the simplest two-dimensional lattices, namely the square and the triangular lattice. Numerical results are presented for the entropy which are consistent with identical universal properties. However, the absolute values of the entropy are bigger on the geometrically frustra...

The octagonal mesh is a variation of the two-dimensional (2D) mesh topology in which each processing element is connected to its eight closest neighbors. This paper studies the octagonal mesh as a topology for a wormhole-routed multiprocessor. A unicast routing algorithm and two multicast routing algorithms are presented and shown to be deadlock-free. Simulation results are given that compare m...

Inelastic neutron scattering measurements on the itinerant antiferromagnet CaCo_{2-y}As_{2} at a temperature of 8 K reveal two orthogonal planes of scattering perpendicular to the Co square lattice in reciprocal space, demonstrating the presence of effective one-dimensional spin interactions. These results are shown to arise from near-perfect bond frustration within the J_{1}-J_{2} Heisenberg m...

We present molecular dynamics simulation evidence of spontaneous formation of quasi-one-dimensional (Q1D) hydrogen gas hydrates within single-walled carbon nanotubes (SW-CNTs) of nanometer-sized diameter (1-1.3 nm) near ambient temperature. Contrary to conventional 3D gas hydrates in which the guest molecules are typically contained in individual and isolated cages in the host lattice, the gues...

We consider the Hubbard model for electrons in a two-dimensional quasiperiodic tiling using the Hartree–Fock approximation. Numerical solutions are obtained for the first three square approximants of the perfect octagonal tiling. At half-filling, the magnetic state is antiferromagnetic. We calculate the distributions of local magnetizations and their dependence on the local environments as U is...

in this paper, two dimensional natural convection heat transfer in non-square cavities such as triangle, trapezoid, quadrant-circle and semi-circular are investigated via lattice boltzmann method. the prandtl number is taken as 0.71 that corresponds to that of air. the results show that, when the flow pattern consists of two rotating cell, there is a extremum point in the variations of the loca...

In lasers with nonorthogonal eigenmodes the excess-noise factor K can be large, especially in unstable-cavity lasers with hard-edged intracavity apertures. To the best of our knowledge, we report the first detailed study of the dependence of K on aperture shape. Calculations and measurements of K for unstable-cavity lasers with variable-size apertures of triangular, square, pentagonal, hexagona...

We generalize the Toda lattice (or Toda chain) equation to the square lattice, i.e., we construct an integrable nonlinear equation for a scalar field taking values on the square lattice and depending on a continuous (time) variable, characterized by an exponential law of interaction in both discrete directions of the square lattice. We construct the Darboux-Bäcklund transformations for such lat...

We present a set of exactly solvable Ising models, with half-odd-integer spinS on a square-type lattice including a quartic interaction term in the Hamiltonian. The particular properties of the mixed lattice, associated with mixed half-odd-integer spin-(S,1/2) and only nearest-neighbor interaction, allow us to map this system either onto a purely spin-1/2 lattice or onto a purely spinS lattice....