title: Observation of decoherence in a carbon nanotube mechanical resonator.
abstract: In physical systems, decoherence can arise from both dissipative and dephasing processes. In mechanical resonators, the driven frequency response measures a combination of both, whereas time-domain techniques such as ringdown measurements can separate the two. Here we report the first observation of the mechanical ringdown of a carbon nanotube mechanical resonator. Comparing the mechanical quality factor obtained from frequency- and time-domain measurements, we find a spectral quality factor four times smaller than that measured in ringdown, demonstrating dephasing-induced decoherence of the nanomechanical motion. This decoherence is seen to arise at high driving amplitudes, pointing to a nonlinear dephasing mechanism. Our results highlight the importance of time-domain techniques for understanding dissipation in nanomechanical resonators, and the relevance of decoherence mechanisms in nanotube mechanics.
authors.affiliation: Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, The Netherlands.
authors.forename: Ben H
authors.initials: BH
authors.lastname: Schneider
authors.affiliation: Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, The Netherlands.
authors.forename: Vibhor
authors.initials: V
authors.lastname: Singh
authors.affiliation: Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, The Netherlands.
authors.forename: Warner J
authors.initials: WJ
authors.lastname: Venstra
authors.affiliation: Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, The Netherlands.
authors.forename: Harold B
authors.initials: HB
authors.lastname: Meerwaldt
authors.affiliation: Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, The Netherlands.
authors.forename: Gary A
authors.initials: GA
authors.lastname: Steele