2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/145613We study numerically the behavior of qubit coupled to a quantum dissipative driven oscillator (resonator). Above a critical coupling strength the qubit rotations become synchronized with the oscillator phase. In the synchronized regime, at certain parameters, the qubit exhibits tunneling between two orientations with a macroscopic change of number of photons in the resonator. The life times in these metastable states can be enormously large. The synchronization leads to a drastic change of qubit radiation spectrum with appearance of narrow lines corresponding to recently observed single artificial-atom lasing [O. Astafiev {\it et al.} Nature {\bf 449}, 588 (2007)].revtex 4 pages, 6 figs, research at http://www.quantware.ups-tlse.fr/SuperconductivityOther Condensed MatterChaotic DynamicsQuantum Physicstext