论文标题
粘性液体中布朗力噪声的纳米力学测量
Nanomechanical Measurement of the Brownian Force Noise in a Viscous Liquid
论文作者
论文摘要
我们研究了热力的热力的光谱特性，从而在粘性液体中引起了连续机械系统的布朗运动（即纳米力学束谐振器）。为此，我们执行两组实验集。首先，我们测量谐振器在其中心基本模式周围位置波动的功率谱密度（PSD）。然后，我们通过用谐波力驱动它与基本模式相结合，测量谐振器的频率依赖性线性响应。这两个测量值使我们能够在其基本模式下确定作用在结构上的布朗力噪声的PSD。从跨越频率范围的多个谐振器中提取的力噪声的PSD显示“彩色频谱”。使用单模理论，我们表明，围绕谐振器的基本谐振，力噪声的PSD遵循粘性液体中刀片旋转的耗散 - 凭借波动散热定理。
We study the spectral properties of the thermal force giving rise to the Brownian motion of a continuous mechanical system -- namely, a nanomechanical beam resonator -- in a viscous liquid. To this end, we perform two separate sets of experiments. First, we measure the power spectral density (PSD) of the position fluctuations of the resonator around its fundamental mode at its center. Then, we measure the frequency-dependent linear response of the resonator, again at its center, by driving it with a harmonic force that couples well to the fundamental mode. These two measurements allow us to determine the PSD of the Brownian force noise acting on the structure in its fundamental mode. The PSD of the force noise extracted from multiple resonators spanning a broad frequency range displays a "colored spectrum". Using a single-mode theory, we show that, around the fundamental resonances of the resonators, the PSD of the force noise follows the dissipation of a blade oscillating in a viscous liquid -- by virtue of the fluctuation-dissipation theorem.
