LUTTINGER ANOMALY EXPONENT OF MOMENTUM DISTRIBUTION IN THE HUBBARD CHAIN

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 4kF 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. © 1990.