Quantum Friction of Micromechanical Resonators at Low Temperatures

Quantum friction of micromechanical resonators at low temperatures.

Dissipation of micro- and nanoscale mechanical structures is dominated by quantum-mechanical tunneling of two-level defects intrinsically present in the system. We find that at high frequencies-usually, for smaller, micron-scale structures-a novel mechanism of phonon pumping of two-level defects gives rise to weakly temperature-dependent internal friction, Q-1, concomitant to the effects observ...

High-frequency micromechanical columnar resonators.

High-frequency silicon columnar microresonators are fabricated using a simple but effective technological scheme. An optimized fabrication scheme was invented to obtain mechanically protected microcolumns with lateral dimensions controlled on a scale of at least 1 μm. In this paper, we investigate the influence of the environmental conditions on the mechanical resonator properties. At ambient c...

Nonlinear Dynamics of Nanomechanical and Micromechanical Resonators

Quantum Turbulence at Very Low Temperatures: Status and Prospects

The theory of how turbulent energy decays via a Richardson cascade is well-established for classical fluids, and it also seems to apply to the case of so-called co-flowing He II turbulence in the range from the superfluid transition temperature 7\ down to ~1 K, where its behaviour is similar to that of a classical fluid. For pure superfluids, e.g. He II in the mK range or He-B in the jiK range,...

Gallium nitride micromechanical resonators for IR detection

This paper reports on a novel technology for low-noise un-cooled detection of infrared (IR) radiation using a combination of piezoelectric, pyroelectric, electrostrictive, and resonant effects. The architecture consists of a parallel array of high-Q gallium nitride (GaN) micro-mechanical resonators coated with an IR absorbing nanocomposite. The nanocomposite absorber converts the IR energy into...