Abstract
The Hubbard model with unconstrained hopping of the particles on a lattice is solved exactly. It is shown that in this case the kinetic energy commutes with the interaction part, i.e., the model is essentially trivial. The thermodynamics is worked out explicitly. One finds that the results of the quasichemical approximation for the occupation probability of lattice sites are exact for this model. The ground state is insulating at half-filling and U>0 and is conducting otherwise.
- Received 2 March 1989
DOI:https://doi.org/10.1103/PhysRevB.40.7252
©1989 American Physical Society
