Static spin-dependent forces between heavy quarks in the classical approximation to dual QCD

We compute the static spin-dependent forces $V_S\mathrm{}\left(R\right)\mathrm{}$ (proportional to ${\sigma }_1·{\sigma }_2$) and $V_T\mathrm{}\left(R\right)\mathrm{}$ (proportional to $3{\sigma }_1·\hat{\mathrm{R}}{\sigma }_2·\hat{\mathrm{R}}-{\sigma }_1·{\sigma }_2$) between two quarks separated by R. This is done by treating the (weak) spin-dependent effects as a perturbation on the spin-independent potentials and fields computed earlier for dual QCD. What results is a definite prediction for the heavy-quark potentials which are similar to, but different in form from, those used in phenomenological treatments. Calculations of the masses and splittings of heavy-quark states using our potentials will provide a further test of the dual superconductor picture of QCD.