Some aspects of functional Bethe ansatz

Abstract

The validity of Bethe ansatz wave function without the backward scattering for the problem of impurity in correlated hosts with periodic boundary condition is illustrated by a simple example of quantum mechanics. An long being overlooked point in solving Hubbard model by means of Bethe ansatz is indicated. A possible repairing on the Hamiltonian is suggested so that the well known solution is still valid.