Spinon-Holon Recombination in Gutzwiller Projected Wave Functions
  The Gutzwiller projection is shown to induce nontrivial correlation between the spinon and the holon in the slave Boson theory of the $t-J$ model. We find this correlation is responsible some subtle differences between the slave Boson mean field theory and the Gutzwiller projected wave function(GWF), among which the particle-hole asymmetry in the quasiparticle weight calculated from the GWF is a particular example. 
Hong-Yu Yang and Tao Li