Lieb-Thirring and Cwickel-Lieb-Rozenblum inequalities for perturbed   graphene with a Coulomb impurity
  We study the two dimensional massless Coulomb-Dirac operator restricted to its positive spectral subspace and prove estimates on the negative eigenvalues created by electromagnetic perturbations. 
Sergey Morozov and David M\"uller
math-ph math.MP math.SP quant-ph