Exact results for three electrons in a linear chain within the Hubbard model

In this work we analyzed the ground-state symmetry for the cases of three particles in a linear chain, using the generalized Hubbard Hamiltonian and a previously developed real-space mapping method. The method is based oil mapping the correlated many-body problem onto an equivalent site- and bond-impurity one-body problem in a higher dimensional space, where the problem can be solved exactly. For the case of three particles, it is obtained a ground-state when the correlated hopping interactions are included. A clear asymmetry between electrons and holes is observed due to the bond-charge interactions. The three-particle problem is analyzed by looking at the phase diagram for the bound state. (C) 2002 Elsevier Science B.V. All rights reserved.