Abstract
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, = 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.
Publisher
National Academy of Sciences of the Republic of Armenia