Experimental study of free surface of superfluid 3He

在这个项目中，我们已经澄清，液体3 He的表面张力的温度依赖性低于100 mK几乎淬火（平坦之间0和100 mK），也有一个非常小的峰值附近100 mK。实验结果进行了分析的基础上的假设，本地熵密度图片是正确的。表面张力与温度关系的主导项是T^2，T^2项系数很小是由于表面附近的费米能密度小于体相液体的费米能密度，然后随着密度的减小而增大，当T^2系数很小时，次高阶项变得重要。下一项应该取决于强关联费米液体（^3He）的模型。我们采用了三泽的模型，该模型将液态^3He描述为近亚磁性模型。在这个理论中，下一个前导项是cT^4ln（T/T^*）。通过适当的拟合，我们可以很好地再现实验中观测到的小的极大值，从而可以从低温下表面张力的精确测量中推断出有关液态~ 3 He的一些重要信息，并在超流^3He表面零声反射的实验中取得了一些进展。不幸的是，我们不能在项目期间进行实验，但第一个实验将很快完成。

In this project we have clarified that the temperature dependence of the surface tension of liquid 3He below 100 mK is almost quenched (flat between 0 and 100 mK) and also there is a very small peak around 100 mK.The experimental results were analyzed based on the assumption that the local entropy density picture is correct. The leading term of the temperature dependence of surface tension is T^2 and the very small coefficient of T^2 term is the result that the Fermi energy density near the surface becomes smaller than that of bulk liquid and then gets much bigger as the density decreases more.As the coefficient of T^2 becomes very small, the next higher order term becomes important. The next term should be dependent on the model of the strongly correlated Fermi-liquid (^3He). We adopted the Misawa's model which describes the liquid ^3He as the nearly meta-magnetic model. In this theory the next leading term is cT^4ln(T/T^*). By a suitable fitting, we could reproduce the small maximum observed in the experiment perfectly.Thus we could deduce some important information on liquid 3He from the precise measurement of surface tension in the low temperature.We also have made some progress in the experiment on zero sound reflection at the superfluid ^3He surface. Unfortunately we could not perform the experiment during the project period but the first experiment will be done pretty soon.