Charge excitations in the one-dimensional Hubbard model

On the basis of the Bethe ansatz solution, the characteristic properties of charge excitations are investigated for the one-dimensional Hubbard model by inserting a charged hole into the Mott insulator. The density of states for the charged hole shows divergent behavior in the lower-energy region, whose connection is discussed analytically with the compressibility and magnitude of the Hubbard gap. Momentum-dependent susceptibility is also investigated within the framework of the quasiparticle formalism in the Bethe ansatz method. The logarithmic anomaly of the susceptibilty for the charged hole near 4kF (kF being the Fermi momentum in the noninteracting case) is considerably enhanced in the vicinity of the Mott insulating phase, while it is suppressed at the insulating phase due to the formation of the Hubbard gap.