Indirect Evidence for Lévy Walks in Squeeze Film Damping

Abstract

Molecular flow gas damping of mechanical motion in confined geometries, and its associated noise, is important in a variety of fields, including precision measurement, gravitational wave detection, and MEMS devices. We used two torsion balance instruments to measure the strength and distance-dependence of `squeeze film' damping. Measured quality factors derived from free decay of oscillation are consistent with gas particle superdiffusion in Lévy walks and inconsistent with those expected from traditional Gaussian random walk particle motion. The distance-dependence of squeeze film damping observed in our experiments is in agreement with a parameter-free Monte Carlo simulation. The squeeze film damping of the motion of a plate suspended a distance d away from a parallel surface scales with a fractional power between 1/d and 1/d^2.

5 pages 5 figures accepted for PRD; typo in equation 3 and figure 1 fixed

References in corpus (3)

• Temporal Extent of Surface Potentials between Closely Spaced Metals
• Increased Brownian force noise from molecular impacts in a constrained volume
• Charge Management for Gravitational Wave Observatories using UV LEDs

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