Many-body effects in the persistent current problem

In this work some many-body properties of isolated mesoscopic rings are investigated. Second quantization and tight-binding models for systems of spinless fermions and fermions with spin are used to derive an expression for the persistent current. The results obtained for non-interacting systems are in satisfactory agreement with both experimental measurements and other theoretical results. Then a Coulomb repulsion is considered for a system of interacting fermions and a variational approach is adopted. We attempt to improve the description of the system by introducing rotations of the spin-quantization axis on each site. Then we go on to show how the emergent Hartree–Fock equations may be treated, what kind of effects have to be considered and how the trial wave functions can be chosen accordingly.