Phase transitions in one-dimensional Hubbard model with degeneracy

A solution in quadratures of the doubly orbitally degenerate Hubbard chain with strong correlations of the electrons in one orbital is obtained by means of the spin-symmetrized Bethe–Gaudin–Yaug ansatz. The correlation gap in the dielectric phase is due to both interorbital Coulomb repulsion of the electrons and their Hund exchange interaction. The possibilities of a Mort transition are investigated.