  We calculate the spectral densities of electric and magnetic gluons at zero
temperature in color-superconducting quark matter in the color-flavor-locking
(CFL) phase. We find a collective excitation, a plasmon, at energies smaller
than two times the gap parameter and momenta smaller than about eight times the
gap. The dispersion relation of this mode exhibits a minimum at some nonzero
value of momentum, indicating a van Hove singularity.
