Spin-charge recombination and superconductivity in the t-J model

spin-charge binding mechanism is analyzed using the Schwinger boson representation of the two-dimensional t-J model. In the normal state spinons are paired into singlets which evolve out of the antiferromagnetic phase at half-filling. The singlets induce, via the hopping term, a pairing of holons and bind with the latter. The d(x2-y2) symmetry of the order parameter and the shape of the T-c vs doping curve, observed in cuprate superconductors, emerge naturally as a consequence of the symmetry of the spinon pairs, thus connecting superconductivity with quantum spin fluctuations in the insulator.