Comment on "Supercurrent in a room temperature Bose-Einstein magnon   condensate"
  The comment explains that the preprint arXiv:1503.0042 has not presented persuasive theoretical or experimental arguments of existence of spin supercurrents in a magnon condensate prepared in a room temperature yttrium-iron-garnet magnetic film because the authors did not check known criteria for existence of spin supercurrents in magnetically ordered materials. Also they did not compare their supercurrent interpretation with a competing and more realistic scenario of transport by spin diffusion. 
E.B. Sonin
cond-mat.other