2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/100502For strongly correlated electrons the relation between total number of charge carriers $n_e$ and the chemical potential $μ$ reveals for large Coulomb energy the apparently paradoxical pinning of $μ$ within the Mott gap, as observed in high-$T_c$ cuprates. By unravelling consequences of the non-trivial topology of the charge gauge U(1) group and the associated ground state degeneracy we found a close kinship between the pinning of $μ$ and the zero-temperature divergence of the charge compressibility $κ\sim\partial n_e/\partialμ$, which marks a novel quantum criticality governed by topological charges rather than Landau principle of the symmetry breaking.4+ pages, 2 figures, typos corrected, version as publishedStrongly Correlated ElectronsSuperconductivitytext