论文标题
零温度介电常数和液体密度$^4 $ He的精确测量值
Precision measurements of the zero temperature dielectric constant and density of liquid $^4$He
论文作者
论文摘要
三维微波腔的谐振频率明确取决于填充腔的材料的介电常数，使其成为探测材料特性的理想系统。特别是，介电恒定测量值使人们可以通过Clausius-Mossotti关系提取氦密度。通过用超氟氦气填充圆柱形铝腔，我们可以对液体$^4 $ He的电介质常数进行精确测量，以饱和蒸汽压力30-300 mk的温度范围，并在30 mk处的0-25.0 bar的压力，本质上是$^4 $^4 $ He He He Hea的零温度限制。在回顾了先前的测量值之后，我们发现在零温度极限和中等差异中，低频和高频确定介电常数之间的系统差异，并以前报道的压力依赖性密度值。我们的精度测量表明，3D微波腔是精炼先前测量值的氦气值的有前途的选择，并在计量学中使用了潜在的应用。
The resonant frequencies of three-dimensional microwave cavities are explicitly dependent on the dielectric constant of the material filling the cavity, making them an ideal system for probing material properties. In particular, dielectric constant measurements allow one to extract the helium density through the Clausius-Mossotti relation. By filling a cylindrical aluminum cavity with superfluid helium, we make precision measurements of the dielectric constant of liquid $^4$He at saturated vapor pressure for range of temperatures 30 -- 300 mK and at pressures of 0-25.0 bar at 30 mK, essentially the zero temperature limit for the properties of $^4$He. After reviewing previous measurements, we find systematic discrepancy between low and high frequency determination of the dielectric constant in the zero-temperature limit and moderate discrepancy with previously reported values of pressure-dependent density. Our precision measurements suggest 3D microwave cavities are a promising choice for refining previously measured values in helium, with potential applications in metrology.
