The spin-½ antiferromagnetic Heisenberg model on a square lattice is used to describe the
dynamics of the spin degrees of freedom of undoped copper oxides. Even though the model …

A modified spin-wave theory for the Heisenberg antiferromagnet (scrH= J) is formulated
under the assumption of zero sublattice magnetization in the same way with the Heisenberg …

In this article we review numerical studies of the quantum Heisenberg antiferromagnet on a
square lattice, which is a model of the magnetic properties of the undoped “precursor …

The low temperature and large volume effects in the d= 2+ 1 antiferomagnetic quantum
Heisenberg model are dominated by magnon excitations. The leading and next-to-leading …

Transverse susceptibility (χ⊥), spin stiffness constant (ρ s), spin-wave velocity (cs),
staggered magnetization (M+) and the ground-state energy (E 0) of the T= 0, spin-(1/2 …

抄録 A two-dimensional square-lattice Hubbard model is investigated. A slave-fermion
formulation, in which the electron operator is expressed by a combination of bose operators …

Abstract Quantum Monte Carlo results for the specific heat c of the two-dimensional Hubbard
model are presented. At half filling it was observed that c∼ T 2 at very low-temperatures …

Experimental evidence for the quasi-one-dimensional (1D) antiferromagnetism of CuO is
presented in a framework of Heisenberg model. We have obtained an experimental …

We show that the conventional spin-wave theory cannot give a correct phase diagram for the
frustrated square-lattice antiferromagnet. We present a modified spin-wave theory for this …

Two-dimensional Antiferromagnetic Heisenberg model is investigated by a mean field
theory, where order parameter corresponding to the resonating valence bond (RVB) state is …