超声干涉仪测量液态~ 4 He的初声
Ultrasonic Interferometer for First-Sound Measurements of Confined Liquid 4He
摘要：
我们提出了一种新的技术，用于探测量子流体在限制几何的性质。我们已经将液体4 He限制在由玻璃晶片形成的微流体装置内，其中一个维度是在微观尺度上。用超声模拟法布里-珀罗干涉法测量了~ 4 He的第一声，它可以作为探测λ点（$T_λ$）附近临界行为的探针。液体$^4$ He的所有热力学性质都可以从第一声和热容测量中推导出来，尽管对后者已经做了相当多的实验工作，但没有报道过对于小于几十微米的精确受限几何形状的第一声测量。在这项工作中，我们报告的等压第一声测量液体$^4$他局限在小至5 $μ$ m的空腔。我们的实验装置允许我们将液体加压至~ 25 bar，而不会导致受限几何形状的变形，该压力比先前报道的类似微流体装置大约4倍。我们的初步结果表明，人们可以观察到有限尺寸效应和验证标度律，通过使用类似的设备与更小的限制。
英文摘要：
We present a new technique for probing the properties of quantum fluids in restricted geometries. We have confined liquid 4He within microfluidic devices formed from glass wafers, in which one dimension is on the micro scale. Using an ultrasonic analog to Fabry-Perot interferometry, we have measured the first-sound of the confined liquid 4He, which can be a probe of critical behavior near the lambda point ($T_λ$). All thermodynamic properties of liquid $^4$He can be derived from first-sound and heat capacity measurements, and although quite a bit of experimental work has been done on the latter, no measurement of first-sound has been reported for a precisely confined geometry smaller than a few tens of micrometers. In this work, we report measurements of isobaric first sound in liquid $^4$He confined in cavities as small as ~ 5 $μ$m. Our experimental set-up allows us to pressurize the liquid up to ~ 25 bar without causing deformation of the confined geometry, a pressure which is about 4 times larger than previously reported with similar microfluidic devices. Our preliminary results indicate that one can possibly observe finite-size effects and verify scaling laws, by using similar devices with smaller confinement.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
