Superfluid $^3$He in globally isotropic random media
Abstract
Recent theoretical and experimental studies of superfluid He in aerogels with a global anisotropy, e.g., due to an external stress, have definitely shown that the A-like phase with an equal spin pairing (ESP) in such aerogel samples is in the ABM (or, axial) pairing state. In this paper, the A-like phase of superfluid He in globally {\it isotropic} aerogel is studied in details by assuming a weakly disordered system in which singular topological defects are absent. Through calculation of the free energy, a disordered ABM state is found to be the best candidate of the pairing state of the globally isotropic A-like phase. Further, it is found through a one-loop renormalization group calculation that the coreless continuous vortices (or, vortex-skyrmions) are irrelevant to the long-distance behavior of the disorder-induced textures, and that the superfluidity is maintained in spite of lack of the conventional off-diagonal long range order. Therefore, the globally isotropic A-like phase at weak disorder is, like in the case with a global stretched anisotropy, a superfluid glass with the ABM pairing.
Keywords
Cite
@article{arxiv.0811.2292,
title = {Superfluid $^3$He in globally isotropic random media},
author = {Ryusuke Ikeda and Kazushi Aoyama},
journal= {arXiv preprint arXiv:0811.2292},
year = {2009}
}
Comments
Revised version accepted for publication in Phys.Rev.B