Comment on “Poynting vector, heating rate, and stored energy in structured materials: A first-principles derivation”

Abstract

In Phys. Rev. B 80, 235120 (2009), M. G. Silveirinha criticizes our work on Poynting's theorem and energy conservation in systems with bounded media [EPL 81, 67005 (2008)], especially with regard to our argumentation toward $\mathbf{S}=\frac{1}{{\ensuremath{\mu}}_{0}}(\mathbf{E}\ifmmode\times\else\texttimes\fi{}\mathbf{B})$ as a generally valid energy flux vector. We fully rebut the criticism, point out that it is based on undue comparison, clear up some misunderstandings and show that Silveirinha's approach is rather a restricted than a general one.