  We investigate the effect of hole doping on the strong-coupling Hubbard model
at half-filling in spatial dimensions $D\ge 1$. We start with an
antiferromagnetic mean-field description of the insulating state, and show that
doping creates solitons in the antiferromagnetic background. In one dimension,
the soliton is topological, spinless, and decoupled from the background
antiferromagnetic fluctuations at low energies. In two dimensions and above,
the soliton is non-topological, has spin quantum number 1/2, and is strongly
coupled to the antiferromagnetic fluctuations. We derive the effective action
governing the quasiparticle motion, study the properties of a single carrier,
and comment on a possible description at finite concentration.
