Hidden non-Abelian gauge symmetries in doped planar antiferromagnets

We investigate the possibility of hidden non-Abelian local phase symmetries in large-U doped planar Hubbard antiferromagnets, believed to simulate the physics of two-dimensional (magnetic) superconductors. We present a spin-charge separation ansatz, appropriate to incorporate holon spin flip, which allows for such a hidden local gauge symmetry to emerge in the effective action. The group is of the form SU(2)xU(S)(1)xU(em)(1), where SU(2) is a local non-Abelian group associated with the spin degrees of freedom, U-em(1) is that of ordinary electromagnetism, associated with the electric charge of the holes, and U-S(1) is a "statistical" Abelian gauge group pertaining to the fractional statistics of holes on the spatial plane. In certain regime of the parameters of the model, namely, strong U-S(1) and weak SU(2), there is the possibility of dynamical formation of a holon condensate. This leads to a dynamical breaking of SU(2)-->U(1). The resulting Abelian effective theory is closely related to an earlier model proposed as the continuum limit of large-spin planar doped antiferromagnets, which lead to an unconventional scenario for two-dimensional parity-invariant superconductivity.