Stability of Ground States of 2d Strongly Asymmetric Correlated-Hopping Hubbard Model

The asymmetric correlated-hopping Hubbard model is analysed perturbatively for large values of the Coulomb interaction U. An effective Hamiltonian is obtained up to terms of the order U ^–3. For d=2 and in the limit of the strong asymmetry, the orderings of the ground states are found (confirming earlier nonrigorous results). Their thermal and quantum stability is proved. These results have been obtained by an application of the quantum Pirogov–Sinai theory in the variant developed by Datta, Fernandez, Fröhlich, and Rey-Bellet.