Does the Two-Dimensional t-J Model have Hole Pockets?
  We have calculated the high temperature series for the momentum distribution function n_k of the 2D t-J model to 12th order in inverse temperature. By extrapolating the series to T=0.2J we investigate the possibility of hole pockets in the t-J model. We find no indication of hole pockets at an electron density of n=0.9 with J/t=0.5 or J/t=1.0. 
W. O. Putikka, M. U. Luchini and R. R. P. Singh