VARIATIONAL TREATMENT OF THE ONE-DIMENSIONAL PEIERLS-HUBBARD MODEL - LATTICE DIMERIZATION AND SOLITONS

The one-dimensional SSH Hamiltonian supplemented by an on-site Coulomb interaction is investigated using the Gutzwiller Ansatz. The various expectation values for the correlated ground state are evaluated numer ically (Hubbard-Stratonovich transformation and Monte Carlo simulation ). Within the parameter region studied, the lattice dimerization (for the half-filled band) has lower energy than the spin-density wave grou nd state. Preliminary results for charged and neutral solitons show th at these two inhomogeneous configurations are more and more distinct, both in size and energy, as the Hubbard parameter U increases.