  Jorge Berger shows theoretically in the paper Phys. Rev. B 109, 024501 (2024)
that according to the Ginzburg-Landau theory the persistent current can create
the persistent voltage, i.e. a dc voltage at thermodynamic equilibrium, on
segments of nonuniform superconducting loop. A similar result was published
early and was collaborated experimentally. The persistent power estimated by
Berger is compared with the experimentally observed power. The attention of
experimenters is drawn to the possibility to observe the persistent voltage
thanks to its increase with the number of identical rings connected in series.
