4 papers
Theoretical studies of the phase transition in the anisotropic 2-D square spin lattice
Mohamad Al Hajj, Nathalie Guihery, Jean-Paul Malrieu +1
The phase transition occurring in a square 2-D spin lattice governed by an anisotropic Heisenberg Hamiltonian has been studied according to two recently proposed methods. The first…
Phase transitions in the Shastry-Sutherland lattice
Mohamad Al Hajj, Jean-Paul Malrieu
Two recently developed theoretical approaches are applied to the Shastry-Sutherland lattice, varying the ratio between the couplings on the square lattice and on the oblique…
A self-consistent perturbative evaluation of ground state energies: application to cohesive energies of spin lattices
Mohamad Al Hajj, Jean-Paul Malrieu
The work presents a simple formalism which proposes an estimate of the ground state energy from a single reference function. It is based on a perturbative expansion but leads to no…
A renormalized excitonic method in terms of block excitations. Application to spin lattices
Mohamad Al Hajj, Jean-Paul Malrieu, Nathalie Guihéry
Dividing the lattice into blocks with singlet ground state and knowing the exact low energy spectrum of the blocks and of dimers (or trimers) of blocks, it is possible to approach…