Dynamical Properties of the Phase-Separation Interface of ^3He-^4He Liquid Mixture.

在研究过饱和超流体^3He-^4He混合物中的成核现象时，我们认识到核与周围液体混合物界面的动力学行为的重要性，即界面的生长系数。我们的实验旨在得到生长系数的温度依赖性。为此，我们采取了一种方法，通过接口测量声音的传输系数(10 MHz)。由于声在^3He-^4He混合物中的衰减很大，我们发展了一种可以连续改变界面位置的方法。我们的主要结果是：(1)生长系数在70mK以下开始增加，与温度的关系约为1/T^2；(2)在流体力学条件下，生长系数的大小比预期的大得多，例如，在10mK时，差异是10^3倍。这些结果对于我们理解成核现象，特别是在伴随能量耗散的量子成核区域，是非常重要的。

In the study of nucleation phenomena in supersaturated super fluid ^3He-^4He mixtures, we recognized the importance of the dynamical behavior of the interface between the nucleus and the surrounding liquid mixture, that is, the growth coefficient of the interface.Our present experiment aimed at getting the temperature dependence of the growth coefficient. For that purpose, we took a way to measure the transmission coefficient of sound(10MHz)through the interface. Because of the very large attenuation of sound in ^3He-^4He mixtures, we developped a method in which the position of the interface can be changed continuously.The main parts of our results are ; (1)the growth coefficient starts increasing below about 70mK and, the temperature dependence is approximately 1/T^2, (2)the magnitude of the growth coefficient is much larger than expected from the consideration in a hydrodynamic regime, for example, at 10mK the difference is a factor of 10^3. These results are very important for our understanding of the nucleation phenomena, especially in the region of quantum nucleation accompanied with energy dissipation.