  In this paper we reexamine the problem of the separation of spin and charge
degrees of freedom in two dimensional strongly correlated systems. We establish
a set of sufficient conditions for the occurence of spin and charge separation.
Specifically, we discuss this issue in the context of the Heisenberg model for
spin-1/2 on a square lattice with nearest ($J_1$) and next-nearest ($J_2$)
neighbor antiferromagnetic couplings. Our formulation makes explicit the
existence of a local SU(2) gauge symmetry once the spin-1/2 operators are
replaced by bound states of spinons. The mean-field theory for the spinons is
solved numerically as a function of the ratio $J_2/J_1$ for the so-called s-RVB
Ansatz. A second order phase transition exists into a novel flux state for
$J_2/J_1>(J_2/J_1)_{{\rm cr}}$. We identify the range $0<J_2/J_1<(J_2/J_1)_{\rm
cr}$ as the s-RVB phase. It is characterized by the existence of a finite gap
to the elementary excitations (spinons) and the breakdown of all the continuous
gauge symmetries. An effective continuum theory for the spinons and the gauge
degrees of freedom is constructed just below the onset of the flux phase. We
argue that this effective theory is consistent with the deconfinement of the
spinons carrying the fundamental charge of the gauge group. We contrast this
result with the study of the one dimensional quantum antiferromagnet within the
same approach. We show that in the one dimensional model, the spinons of the
gauge picture are always confined and thus cannot be identified with the
gapless spin-1/2 excitations of the quantum antiferromagnet Heisenberg model.
