|Comment on "Equilibrum spin currents: Non-Abelian Gauge Invariance and Color Diamagnetism in Condensed Matter"|
|López A., Medina E., Bolívar N., Berche B.|
|ArXiv : arxiv:0902.4635 [PDF]|
In a recent paper [Phys. Rev. Lett. 101, 106601], I. V. Tokatly addresses a non Abelian formulation of spin orbit interaction in condensed matter, restricting to a gauge symmetric scenario. In this comment we draw attention on the relevance of gauge symmetry breaking on such formulation and point out why this is a necessary ingredient for properly describing the associated diamagnetic color currents.