Emergent Quantum Jumps in a Nano-Electro-Mechanical System

We describe a nano-electromechnical system that exhibits the "retroactive" quantum jumps discovered by Mabuchi and Wiseman [Phys. Rev. Lett. 81, 4620 (1998)]. This system consists of a Cooper-pair box coupled to a nano-mechanical resonator, in which the latter is continuously monitored by a single-electron transistor or quantum point-contact. Further, we show that these kinds of jumps, and the jumps that emerge in a continuous quantum non-demolition measurement are one and the same phenomena. We also consider manipulating the jumps by applying feedback control to the Cooper-pair box.