The spectral properties of the 1D Hubbard model are obtained from quantum Monte Carlo simulations on large systems (N=84) 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±0.05. An exact sum rule for spin and charge excitations is fulfilled accurately with deviations of at most 10% only around 2kF.
Preuss, R., Muramatsu, A., von der Linden, W., Dieterich, P., Assaad, F. F., & Hanke, W. (1994). Spectral Properties of the One-Dimensional Hubbard Model. Physical Review Letters, 73(5), 732. https://doi.org/10.1103/PhysRevLett.73.732