  Using first-principles techniques, we calculate the renormalization of the
electron Fermi velocity and the vibrational lifetimes arising from
electron-phonon interactions in doped bilayer graphene and in graphite and
compare the results with the corresponding quantities in graphene. For similar
levels of doping, the Fermi velocity renormalization in bilayer graphene and in
graphite is found to be approximately 30% larger than that in graphene. In the
case of bilayer graphene, this difference is shown to arise from the interlayer
interaction. We discuss our findings in the light of recent photoemission and
Raman spectroscopy experiments.
