It is demonstrated that recent NMR results in ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ indicate that at 2.65 mK, the liquid makes a second-order transition to a phase in which the "spin-orbit" symmetry is spontaneously broken. The hypothesis that this phase is a BCS-type phase in which pairs form with $l$ odd, $S=1\mathrm{}$, $S_z=\pm 1$ leads to reasonable agreement with both NMR and thermodynamic data, but involves some difficulties as to stability.

• Received 5 September 1972

DOI:https://doi.org/10.1103/PhysRevLett.29.1227

This article appears in the following collection:

Letters from the Past - A PRL Retrospective

2008 marked PRL’s 50th anniversary. As part of the celebrations a collection of milestone Letters was started. The collection contains Letters that have made long-lived contributions to physics, either by announcing significant discoveries, or by initiating new areas of research.