2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/98606We connect three phenomena in which a coherent electromagnetic field could be generated: polariton condensation, phase-locking in arrays of underdamped Josephson junctions, and lasing. All these phenomena have been described using Dicke-type models of spins coupled to a single photon mode. These descriptions may be distinguished by whether the spins are quantum or classical, and whether they are strongly or weakly damped.6 pages, RevTex. To appear in a special edition of Solid State Communications on "Quantum Phases at the Nanoscale"Mesoscale and Nanoscale PhysicsStrongly Correlated ElectronsSuperconductivitytext