Intra-Landau-level cyclotron resonance in bilayer graphene

Interaction driven integer quantum-Hall effects are anticipated in graphene bilayers because of the near degeneracy of the eight Landau levels which appear near the neutral system Fermi level. We predict that an intra-Landau-level cyclotron resonance signal will appear at some odd-integer filling factors, accompanied by collective modes which are nearly gapless and have approximate k(3/2) dispersion. We speculate on the possibility of unusual localization physics associated with these modes.