  We analyze the t-J model on a square lattice using bosonic spinons and
fermionic holons for low density x of holes. Spinons are paired into singlets,
which condense below a temperature T*. The condensate evolves out of the Mott
phase - preserving its symmetry. For T > T* holons and spinons are confined (by
gauge forces), so that there is no coherent charge propagation. Metallic
conduction and d-wave superconductivity result from separate,
sublattice-preserving, holon hopping processes which originate below T* from a
coupling with the condensate. A simple effective Hamiltonian describing these
processes is derived and solved. Holons form a charge Fermi liquid, becoming
incoherent (confined) above T*. In the superconductor holons hop as pairs,
reducing kinetic energy. The two-sublattice property is the glue that connects
the three phases; its effect can be seen in various correlation functions. The
theory can account for many features of the cuprate superconductors, including
the origin of two-dimensional metallicity.
