THE 1D HEISENBERG ANTIFERROMAGNET MODEL BY THE VARIATION AFTER PROJECTION METHOD
THE 1D HEISENBERG ANTIFERROMAGNET MODEL BY THE VARIATION AFTER PROJECTION METHOD
The 4 sites and 8 sites 1D anti-ferromagnetic Heisenberg chains in the Jordan-Wigner representation are investigated within the standard Hartree-Fock and RPA approaches, both in the symmetry unbroken and in the symmetry broken phases. A translation invariant groundstate, obtained by the projection method as a linear combination of a symmetry-broken …