Luttinger anomaly exponent of momentum distribution in the Hubbard chain

Abstract

The exponent θ of the power-law anomaly for the momentum distribution in the one-dimensional repulsive Hubbard model is calculated by the Bethe ansatz method. We express the exponent of the 4 k F oscillation part of the asymptotic density correlator in terms of the fractional charge of the massless holon excitation. The exponent θ is then obtained assuming the scaling law based on the Luttinger liquid nature of the system. For U→∞ and 0, the present formulation reproduces the correct values θ→ 1 8 and 0, respectively, for any filling. Furthermore our results agree nicely with the Monte Carlo calculation for finite Coulomb interaction. We explicitly show that near half-filling θ takes the value close to 1 8 as long as the Hubbard gap exists.