This comprehensive paragraph by Dieter Forster1
” Physics is a field that thrives on analogies. We can understand, partially at least, superfluid Helium on the basis of concepts borroed from superconductoers, superconductivity with techniques that were developed in the study of ferromagnetismm and we investigate fluctuations in liquid crystals by employing methods developed to understand spin waves in ferro- and antiferromagnets. The analogy is never complete, but it is almost always helpful.
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Footnote
“Hydrodynamic Fluctuations, Broken Symmetry, and Correlation Functions”, Dieter Forster. Monograph, vol. 47 of the FRONTIERS IN PHYSICS series, W.A. Benjamin, Inc. Russian edition by Atomizdat, Moscow, 1981. Reissued in “Advanced Book Classics”, Addison-Wesley, 1990. ↩