QUANTUM LIMIT IN RESONANT VACUUM TUNNELING TRANSDUCERS

We propose an electromechanical transducer based on a resonant-tunnelling configuration that, with respect to the standard tunnelling transducers, allows larger tunnelling currents while using the same bias voltage. The increased current leads to a decrease of the shot noise and an increase of the momentum noise which determine the quantum limit in the system under monitoring. Experiments with micromachined test masses at 42 K could show dominance of the momentum noise over the Brownian noise, allowing observation of quantum-mechanical noise at the mesoscopic scale.