Theory of the quasiparticle excitation in high T$_{c}$ cuprates: quasiparticle charge and nodal-antinodal dichotomy

Abstract

A variational theory is proposed for the quasiparticle excitation in high T$_{c}$ cuprates. The theory goes beyond the usual Gutzwiller projected mean field state description by including the spin-charge recombination effect in the RVB background. The spin-charge recombination effect is found to qualitatively alter the behavior of the quasiparticle charge as a function of doping and cause considerable anisotropy in quasiparticle weight on the Fermi surface.