Spectral Properties of the One-Dimensional Hubbard Model

The spectral properties of the 1D Hubbard model are obtained from quantum Monte Carlo simulations on large systems ($N=84\mathrm{}$) using the maximum entropy method. It is shown for the first time that the one-particle excitations are characterized by dispersive cosinelike bands, in extremely good agreement with slave-boson mean-field ones. Velocities for spin and charge excitations are obtained that lead to a conformal charge $c=0.98\mathrm{}\pm 0.05$. An exact sum rule for spin and charge excitations is fulfilled accurately with deviations of at most 10% only around $2k_F$.