Quantum friction in nanomechanical oscillators at millikelvin temperatures

Abstract

We report low-temperature measurements of dissipation in megahertz-range, suspended, singlecrystal nanomechanical oscillators. At millikelvin temperatures, both dissipation (inverse quality factor) and shift in the resonance frequency display reproducible features, similar to those observed in sound attenuation experiments in disordered glasses and consistent with measurements in larger micromechanical oscillators fabricated from single-crystal silicon. Dissipation in our single-crystal nanomechanical structures is dominated by internal quantum friction due to an estimated number of roughly 50 two-level systems, which represent both dangling bonds on the surface and bulk defects.

Surface dissipation in nanoelectromechanical systems: Unified description with the standard tunneling model and effects of metallic electrodes

“…An estimate for Q −1 (T ) was provided, reproducing correctly the weak ∼ T 1/3 temperature dependence as well as the order of magnitude observed in recent experiments 30,32 . However, the way the Standard Tunneling Model was adapted was not fully correct, and a revision of the results for Q −1 (T ) obtained therein was mandatory.…”

“…Imperfections and the environment surrounding the oscillator result in both a finite linewidth ∆ω and a frequency shift δω with respect to the ideal case. Therefore several works have been devoted to the analysis of the different sources of dissipation present in MEMS and NEMS 22,23,24,25,26,27,28,29,30,31,32 , trying to determine the dominant damping mechanisms and ways to minimize them. Among the different mechanisms affecting semiconductor-based NEMS the most important and difficult to avoid are i) clamping losses h L w t The height above the substrate is h. A schematic view of the surface is given, highlighting imperfections like roughness and adsorbates, which dominate dissipation at low temperatures.…”

Optomechanical analog of two-color electromagnetically induced transparency: Photon transmission through an optomechanical device with a two-level system

“…Such defects can affect the quantum properties of a mechanical resonator [76][77][78]. Usually, the defects are modeled as two-level systems, and they can interact with the mechanical mode through a deformation force.…”

Rapid characterization of microscopic two-level systems using Landau-Zener transitions in a superconducting qubit

“…TLSs are also harmful to Rabi oscillations, leading to a sharp decrease in gate fidelity. [5][6][7][8][9][10][11][12] Since TLSs are ubiquitous in solid-state devices, [13][14][15] it is important to detect and investigate them in order to achieve better qubit performance. 6,16,17 In recent experiments on the mechanism and interaction of TLSs in superconducting qubits, TLSs are detected through the standard energy spectroscopy measurement.…”