Hybrid quantum device with a carbon nanotube and a flux qubit for dissipative quantum engineering

We describe a hybrid quantum system composed of a micrometer-sized carbon nanotube (CNT) longitudinally coupled to a flux qubit. We demonstrate the usefulness of this device for generating high-fidelity nonclassical states of the CNT via dissipative quantum engineering. Sideband cooling of the CNT to its ground state and generating a squeezed ground state, as a mechanical analog of the optical squeezed vacuum, are two additional examples of the dissipative quantum engineering studied here. Moreover, we show how to generate a long-lived macroscopically distinct superposition (i.e., a Schr\"odinger-cat-like) state. This cat state can be trapped, under some conditions, in a dark state, as can be verified by detecting the optical response of control fields.