2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/130434We consider a BCS-type model in the spin formalism and argue that the structure of the interaction provides a mechanism for control over directions of the spin $\vect S$ other than $S_z$, which is being controlled via the conventional chemical potential. We also find the conditions for the appearance of a high-$T_c$ superconducting phase.11 pages, 5 figures v3: section 2 editedHigh Energy Physics - TheorySuperconductivitytext