Projected wave functions and high temperature superconductivity - art. no.217002

We study the Hubbard model with parameters relevant to cuprates using varia tional Monte Carlo for projected d-wave states. For doping 0 < x <less than or similar to> 0.35 we obtain a superconductor whose order parameter Phi ( x) tracks the observed nonmonotonic T-c(x). The variational parameter Delta (var)(x) scales with the (pi, 0) "hump" and T* seen in photoemission. Proj ection leads to incoherence in the spectral function and from the singular behavior of its moments we obtain the nodal quasiparticle weight Z similar to x though the Fermi velocity remains finite as x --> 0. The Drude weight D-low and superfluid density are consistent with experiment and D-low simil ar to Z.