2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/25222We analyze the behavior of systems of two and three qubits made by Josephson junctions, treated in the two level approximation, driven by a radiation mode in a cavity. The regime we consider is a strong coupling one recently experimentally reached for a single junction. Rabi oscillations are obtained with the frequency proportional to integer order Bessel functions in the limit of a large photon number, similarly to the case of the single qubit. A selection rule is derived for the appearance of Rabi oscillations. A quantum amplifier built with a large number of Josephson junctions in a cavity in the strong coupling regime is also described.9 pages, no figures. Version accepted for publication in Physical Review BSuperconductivityAtomic PhysicsQuantum Physicstext