Effect of kinematic spin polarization in half-quantum vortex state on its stability

It has been shown recently [1] that a half-quantum vortex state in systems with equal spin pairing posses, in addition to a regular spin polarization produced by the Zeeman coupling, a spin polarization of purely kinematic nature. We discuss implications of such kinematic spin polarization on the stability of the half-quantum vortex and its possible experimental signatures in candidate equal spin pairing systems such as $\rm Sr_2RuO_4$. \par\noindent [1]~V.\ Vakaryuk and A.\ J.\ Leggett, Phys.\ Rev.\ Lett.\ {\bf 103}, 057003 (2009).