Fak B, Plantevin O, Glyde HR, Mulders N
Departement de Recherche Fondamentale sur la Matiere Condensee, SPSMS/MDN, CEA Grenoble, 38054 Grenoble, France.
Phys Rev Lett. 2000 Oct 30;85(18):3886-9. doi: 10.1103/PhysRevLett.85.3886.
We report the first observation of two-dimensional layer modes in both fully filled and partially filled aerogel. Using complementary high-energy resolution and high statistical precision neutron scattering instruments, and two different 87% porous aerogel samples, we show that the three-dimensional (3D) phonon-roton excitation energies and lifetimes of liquid 4He in aerogel are the same as in bulk 4He within current precision. The layer modes are the excitations that distinguish aerogel from the bulk rather than a difference in the 3D roton energy.
我们报告了在完全填充和部分填充的气凝胶中首次观察到二维层模式。使用互补的高能量分辨率和高统计精度的中子散射仪器，以及两种不同的87%孔隙率的气凝胶样品，我们表明，在当前精度范围内，气凝胶中液态4He的三维（3D）声子-旋子激发能量和寿命与体相4He中的相同。层模式是使气凝胶区别于体相的激发，而不是3D旋子能量上的差异。
