The two-fluid model with superfluid entropy
arXiv:cond-mat/9507038 · doi:10.1007/BF02451645
Abstract
The two-fluid model of liquid helium is generalized to the case that the superfluid fraction has a small entropy content. We present theoretical arguments in favour of such a small superfluid entropy. In the generalized two-fluid model various sound modes of HeII are investigated. In a superleak carrying a persistent current the superfluid entropy leads to a new sound mode which we call sixth sound. The relation between the sixth sound and the superfluid entropy is discussed in detail.
arXiv comment22 pages, latex, published in Nuovo Cimento 16 D (1994) 373