Adamenko I N, Nemchenko K E, Slipko V A, Wyatt A F G
Karazin Kharkov National University, Svobody Square 4, Kharkov 61077, Ukraine.
Phys Rev Lett. 2006 Feb 17;96(6):065301. doi: 10.1103/PhysRevLett.96.065301. Epub 2006 Feb 13.
The thermodynamic properties of anisotropic quasiparticle systems of He II are considered for all degrees of anisotropy. It is shown that the thermodynamic functions of a strongly anisotropic phonon-roton system are mainly determined by rotons at all temperatures. Analytical expressions for the roton thermodynamic functions are obtained for all degrees of anisotropy. The maximum anisotropy is limited by the criterion for thermodynamic stability, which is here derived for the whole temperature range.
针对所有各向异性程度，研究了氦 II 各向异性准粒子系统的热力学性质。结果表明，在所有温度下，强各向异性声子 - 旋子系统的热力学函数主要由旋子决定。得到了所有各向异性程度下旋子热力学函数的解析表达式。最大各向异性受热力学稳定性判据的限制，本文在整个温度范围内推导了该判据。
