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

氦3是费米子，因此在简并区内，氦3准粒子的平均自由程与T^<-2>成正比。在超低温下，它变得很长，局部场论不能接受。在本研究中，我们研究了在上述情况下超流氦3准粒子的散射。今年进行了扭振实验。为了观察边界条件对氦3准粒子散射的影响，我们在样品细胞壁上放置了一层薄薄的氦4。如前文所述，氦3准粒子在超低温下的平均自由程变得很长，这时需要通过滑移修正将实验结果与理论计算进行比较。测量是在改变样品的压力和温度的情况下进行的。将实验结果与无氦4层实验（纯氦3实验）进行了比较。我们的结论是，1。液氦3的温度依赖性和粘度振幅不受氦4薄层的影响。这说明我们的测量方法是好的。我们无法检测到超流体转变温度上方波动的影响。液氦3正相的滑移长度受氦4薄层的影响，特别是在5bar实验中。它的振幅变成纯氦3实验的两倍左右，但在21bar实验中它没有受到影响。这一结果与氦4薄层的第四声结果一致，即氦4薄层的效应在高压下消失。在21 bar实验中，超流相的滑移长度不受氦4层的影响。另一方面，5bar实验得到的结果是，它变成了纯氦3的两倍。这表明即使在氦4薄层上也会发生安德烈夫反射。

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.