  We present a microscopic model for a strongly repulsive electron gas on a 2D
square lattice. We suggest that nearest neighbor Coulomb repulsion stabilizes a
state in which electrons undergo a "somersault" in their internal spin-space
(spin-flux). When this spin-1/2 antiferromagnetic (AFM) insulator is doped, the
charge carriers nucleate mobile, charged, bosonic vortex solitons accompanied
by unoccupied states deep inside the Mott-Hubbard charge-transfer gap. This
model provides a unified microscopic basis for (i) non-Fermi-liquid transport
properties, (ii) mid-infrared optical absorption, (iii) destruction of AFM long
range order with doping, (iv) angled resolved spectroscopy (ARPES), and (v)
d-wave preformed charged carrier pairs. We use the Configuration Interaction
(CI) method to study the quantum translational and rotational properties of
such pairs. The CI method systematically describes fluctuation and quantum
tunneling corrections to the Hartree-Fock approximation and recaptures
essential features of the (Bethe ansatz) exact solution of the Hubbard model in
1D. For a single hole in the 2D AFM plane, we find a precursor to spin-charge
separation. The CI ground state consists of a bound vortex-antivortex pair, one
vortex carrying the charge and the other one carrying the spin of the doping
hole.
