We consider RVB state as a variational estimate for the ground state of Heisenberg antiferromagnet in square lattice. We present numerical calculation of energy, spin-spin correlation function and spin excitation spectrum. We show, that the quantum flactuations reduce of magnetization respect to Neel order. Our results are in good agreement with other methods such as spin-wave calculation a...

  In this paper a simple model calculation of spin wave is given for the ferromagtic layer in ultra thin ferromagnetic/antiferromagnetic bilayer. In this model the magnetic layer is assumed as an isolated layer but the effect of antiferromagnetic layer on ferromagnetic layer and unidirectional anisotropy, is given in the effective field applied on each spin. The thin layer is assumed as two-dim...

Charge and spin transport properties of a clean $SNS$ Josephson junction (triplet superconductor-normal metal-triplet superconductor) are studied using the quasiclassical Eilenberger equation of Green’s function. Our system consists of two p-wave superconducting crystals separated by a Copper nano layer. Effects of thickness of normal layer between superconductors on the spin and charge current...

 In this paper, a system with spin S=3/2 with general isotropic nearest neighbor exchange within a mean field approximation possess is discnssed. We derive equations describing non-Heisenberg isotropic model using coherent states of SU(4) group in real parameters and then obtain dispersion equations of spin wave of dipole and quadrupole branches for a small linear excitation from the ground state.

In this study, the effect of four-spin exchanges between the nearest and next nearest neighbor spins of honeycomb lattice on the phase diagram of S=3/2 antiferomagnetic Heisenberg model is considered with two-spin exchanges between the nearest and next nearest neighbor spins. Firstly, the method is investigated with classical phase diagram. In classical phase diagram, in addition to Neel order,...

In this paper, we reformulate three-nucleon breakup scattering in leading order approximation by considering spin-isospin degrees of freedom. At first, considering the inhomogeneous part of Faddeev equation, which is a valid approximation in high and intermediate energles, we present the Faddeev equation as a function of vector Jacobi momenta and spin and isospin quantum numbers. In this new fo...

  The incommensurate spin -density –wave magnetism of Cr has attracted great interest since its discovery via neutron scattering. Although the existence of spin- density –wave has been confirmed by experiment but the calculations which have been carried out have not been able to predict the correct ground state magnetic phase for chromium yet. To predict the magnetic hyperfine field at nucleus ...