Popis: |
A recently introduced recurrence-relation ansatz applied to the Fermi-Hubbard model gives rise to a soluble model and here is used to calculate several thermodynamic observables. The constraint of unit density per site, density = 1, is applied and some of the results are compared to cases where the constraint is not imposed. The modified model exhibits a continuous phase transition (second order) reminiscent of the integer quantum Hall resistance and a ground state, first-order phase transition. |