Quantum electrodynamics with anisotropic scaling: Heisenberg-Euler   action and Schwinger pair production in the bilayer graphene
  We discuss quantum electrodynamics emerging in the vacua with anisotropic scaling. Systems with anisotropic scaling were suggested by Horava in relation to the quantum theory of gravity. In such vacua the space and time are not equivalent, and moreover they obey different scaling laws, called the anisotropic scaling. Such anisotropic scaling takes place for fermions in bilayer graphene, where if one neglects the trigonal warping effects the massless Dirac fermions have quadratic dispersion. This results in the anisotropic quantum electrodynamics, in which electric and magnetic fields obey different scaling laws. Here we discuss the Heisenberg-Euler action and Schwinger pair production in such anisotropic QED 
M. I. Katsnelson and G. E. Volovik
cond-mat.str-el cond-mat.mes-hall gr-qc hep-ph