1. Probing Bogoliubov quasiparticles in superfluid $^3$He with a 'vibrating-wire like' MEMS device
- Author
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Defoort, M., Dufresnes, S., Ahlstrom, S. L., Bradley, D. I., Haley, R. P., Guénault, A. M., Guise, E. A., Pickett, G. R., Poole, M., Woods, A. J., Tsepelin, V., Fisher, S. N., Godfrin, H., and Collin, E.
- Subjects
Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
We have measured the interaction between superfluid $^3$He-B and a micro-machined goalpost-shaped device at temperatures below $0.2\,T_c$. The measured damping follows well the theory developed for vibrating wires, in which the Andreev reflection of quasiparticles in the flow field around the moving structure leads to a nonlinear frictional force. At low velocities the damping force is proportional to velocity while it tends to saturate for larger excitations. Above a velocity of 2.6$\,$mms$^{-1}$ the damping abruptly increases, which is interpreted in terms of Cooper-pair breaking. Interestingly, this critical velocity is significantly lower than reported with other mechanical probes immersed in superfluid $^3$He. Furthermore, we report on a nonlinear resonance shape for large motion amplitudes that we interpret as an inertial effect due to quasiparticle friction, but other mechanisms could possibly be invoked as well., Comment: J. of Low Temp. Phys. in press
- Published
- 2015
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