Towards a mechanical quantum bit

We propose to realize a mechanical qubit by coupling the mechanical vibrations of a nanotube resonator to a double-quantum dot formed along the suspended nanotube. Nanotubes are the ideal system for such an experiment, since their high mechanical quantum fluctuation amplitude boosts the single-phonon electromechanical coupling strength. We may reach sub-kHz decoherence rate for the mechanical qubit. Such a demonstration would be a breakthrough in quantum science, offering new perspectives for quantum networks and quantum sensing.