%0 Journal Article %T The uniqueness of the invariant polarisation-tensor field for spin-1 particles in storage rings %A D. P. Barber %A A. Kling %A M. Vogt %J Physics %D 2015 %I arXiv %X We argue that the invariant tensor field introduced in [1] is unique under the condition that the invariant spin field is unique, and thereby complete that part of the discussion in that paper. %U http://arxiv.org/abs/1510.07963v1