Quantum dynamics of a resonator driven by a superconducting   single-electron transistor: a solid-state analogue of the micromaser
  We investigate the behavior of a quantum resonator coupled to a superconducting single-electron transistor tuned to the Josephson quasiparticle resonance and show that the dynamics is similar in many ways to that found in a micromaser. Coupling to the SSET can drive the resonator into non-classical states of self-sustained oscillation via either continuous or discontinuous transitions. Increasing the coupling further leads to a sequence of transitions and regions of multistability. 
D.A. Rodrigues, J. Imbers and A.D. Armour