Comment on "Uncertainty Relation for Photons"
  In a recent interesting Letter [Phys. Rev. Lett. 108, 140401 (2012)] I. Bialynicki-Birula and his coauthor have derived the uncertainty relation for the photons in three dimensions. However, some of their arguments are problematical, and this impacts their conclusion. 
Zhi-Yong Wang, Cai-Dong Xiong, and Qi Qiu
quant-ph physics.optics