Behavior of quartz forks oscillating in isotopically pure 4 He in the T ? 0 limit
Behavior of quartz forks oscillating in isotopically pure 4 He in the T ? 0 limit
复制标题
石英叉在 T 中同位素纯 4 He 中振荡的行为？
DOI：
10.1103/physrevb.85.144518
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发表时间：
2012
影响因子：
3.7
通讯作者：
Garg D
中科院分区：
文献类型：
--
作者：
Garg D
我们报道了在低驱动下，名义上32 khz石英音叉在同位素纯超流体中振荡的共振频率和线宽取决于其环境的尺寸。我们确认了叉和细胞内声学模式之间耦合的重要性，并发展了它们耦合动力学的理论来解释观察结果。频率和线宽在几十分钟的时间尺度上是可重复的，但在更长的间隔内可以看到明显的漂移。我们认为这种漂移是由于微小的压力变化引起的声速变化引起的。在高驱动的研究中，我们观察到两个临界速度：cm/s，其中阻力可能增加或减少，取决于线宽；和cm/s，在此之上似乎是完全紊流。在高速行驶时，不同叉之间的阻力表现明显不同，否则看起来非常相似。
We report that at low drives, the resonant frequencies and linewidths of nominally 32-kHz quartz tuning forks oscillating in isotopically pure superfluidHe at10 mK are dependent on the dimensions of their environment. We confirm the importance of coupling between forks and acoustic modes within the cell, and develop a theory of their coupled dynamics to account for the observations. The frequencies and linewidths are reproducible on a time scale of tens of minutes, but pronounced drifts are seen over longer intervals. We suggest that the drifts are attributable to changes in the velocity of sound due to tiny pressure changes. In studies at high drives, we observe two critical velocities:cm/s, where the drag may either increase or decrease, depending on the linewidth; andcm/s, above which there seems to be fully turbulent flow. At high drives, the behavior of the drag differs markedly between forks that appear otherwise to be very similar.