The dynamic spin and charge correlation functions are computed for the one-dimensional t-J model with use of world-line quantum Monte Carlo and the maximum-entropy method. By comparing our results with exactly known limits, we are able to discern the power and limitations of this method. The spin excitation spectrum shows gapless spin excitations for q=2${\mathit{k}}_{\mathit{F}}$ when J≤2t and for q=π when J>3.25t where phase separation occurs. Also, intermediate values of J/t show no spin gap for the large electron filling (${\mathrm{\rho }}_0$=0.75) considered here. For J≤2t, the charge correlations are dominated at high frequencies by excitations which are related to the particle-hole excitations found for J=0, but a low-frequency mode appears at finite values of J, which is likely related to the binding of electron pairs.

• Received 29 January 1992

DOI:https://doi.org/10.1103/PhysRevB.46.3410