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Research of the scattering process of quasi-particle of superfluid 3He using the fourth sound and the torsional oscillator technique

利用第四声和扭转振子技术研究超流体3He准粒子的散射过程

基本信息

批准号：
06452061
负责人：
KODAMA Takao
金额：
$ 4.42万
依托单位：
Osaka City University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06452061/
关键词：
fourth sound torsional oscillator superfluid helium 3

项目摘要

Helium 3 is Fermion, so that the mean free path of the quasi particle of helium 3 is proportional to T^<-2> in a degenerate region. At ultra-low temperature it becomes very long and the local field theory cannot be acceptable. In this research, we studied the scattering of the quasi particle of superfluid helium 3 in a situation mentioned above.In this year torsional oscillator experiment has been carried out. Tosee the influence of the boundary condition to the scattering of the quasi particle of helium 3, we used the thin layr of helium 4 on a sample cell wall. As mentioned above, the mean free path of the helium 3 quasi particle becomes very long at the ultra-low temperature, then the result of the experiments should be compared with the theoretical calculation by the slip correction. The measurements were done changing the pressure and the temperature of the sample. The results were compared with that of the experiment without helium 4 layr (pure helium 3 experiment). Our conclusion are,1. The temperature dependence and the amplitude of the viscosity of the liquid helium 3 are not influenced by the helium 4 thin layr. This shows that our measurement method is good.2. We could not detect the effect of the fluctuation just above the superfluid transition temperature.3. The slip length of the normal phase of liquid helium 3 was affected by helium 4 thin layr, especially in 5bar experiment. Its amplitude becomes about twice of the pure helium 3 experiment, however, in 21bar experiment it was not affected. This result is consistent to the fourth sound result of helium 4 thin layr, that the effect of helium 4 thin layr disappears at high pressure.4. The slip length of the superfluid phase of 21 bar experiment does not show the effect by the helium 4 layr. On the other hand, 5bar experiment gives the result that it becomes as twice as pure helium 3 case. This shows that the Andreev reflection occurs even on helium 4 thin layr.

氦3是费米子，因此氦3准粒子的平均自由程在简并区域与T^成正比<-2>。在超低温下，它变得很长，局域场理论不能被接受。本文研究了超流氦3准粒子在上述情况下的散射，并在今年进行了扭振子实验。为了考察边界条件对氦3准粒子散射的影响，我们在样品池壁上加了氦4薄层。如前所述，氦3准粒子在超低温下的平均自由程变长，实验结果与理论计算结果需进行滑移修正比较。通过改变样品的压力和温度进行测量。并与无氦4层的实验（纯氦3实验）进行了比较。我们的结论是，1.液氦3的粘度的温度依赖性和幅度不受氦4薄层的影响。这表明我们的测量方法是好的.在超流转变温度以上，我们无法探测到涨落的影响.氦4薄层对液氦3正常相的滑移长度有影响，尤其是在5bar实验中。其振幅约为纯氦3实验的两倍，但在21巴实验中不受影响。这一结果与氦4薄层的第四个合理结果一致，即氦4薄层效应在高压下消失. 21巴实验中超流相的滑移长度不受氦4层的影响。另一方面，5巴实验给出的结果是，它变成了纯氦3情况的两倍。这表明即使在氦4薄层上也会发生Andreev反射。