2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/194233We introduce a new model for dark energy in the universe in which a small cosmological constant is generated by ordinary electromagnetic vacuum energy. The corresponding virtual photons exist at all frequencies but switch from a gravitationally active phase at low frequencies to a gravitationally inactive phase at higher frequencies via a Ginzburg-Landau type of phase transition. Only virtual photons in the gravitationally active state contribute to the cosmological constant. A small vacuum energy density, consistent with astronomical observations, is naturally generated in this model. We propose possible laboratory tests for such a scenario based on phase synchronisation in superconductors.5 pages, 1 figure. Replaced by final version, to appear in Int. J. Mod. Phys. DAstrophysicsSuperconductivitytext