Showing papers by "Tobias Donner published in 2010"

Nanomechanical motion measured with an imprecision below the standard quantum limit

Abstract: Nanomechanical oscillators are at the heart of ultrasensitive detectors of force, mass and motion. As these detectors progress to even better sensitivity, they will encounter measurement limits imposed by the laws of quantum mechanics. If the imprecision of a measurement of the displacement of an oscillator is pushed below a scale set by the standard quantum limit, the measurement must perturb the motion of the oscillator by an amount larger than that scale. Here we show a displacement measurement with an imprecision below the standard quantum limit scale. We achieve this imprecision by measuring the motion of a nanomechanical oscillator with a nearly shot-noise limited microwave interferometer. As the interferometer is naturally operated at cryogenic temperatures, the thermal motion of the oscillator is minimized, yielding an excellent force detector with a sensitivity of 0.51 aN Hz(-1/2). This measurement is a critical step towards observing quantum behaviour in a mechanical object.

Measurement of Nanomechanical Motion with Precision Sufficient to Detect Zero-Point Motion

Abstract: We detect the motion of a suspended micro- and nano- mechanical elements, whose fundamental mode of motion has been cooled to within a few 10s of quanta of the ground-state using an ultra-low temperature cryostat.