THE LATEST BUZZ IS THAT THE VACUUM ENERGY OR THE COSMOLOGICAL CONSTANT OR VIRTUAL PARTICLES, ALL ABOUT THE SAME THING, opps did not see the caps. Please excuse me. The latest buzz is that a plain uniform vacuum without matter also has no vacuum energy. That is because the trans=-planckian virtual paerticles cancel the others, hatever that means.
So for their to be vacuum energy (or any of the other representations) the vacuum must be perturbed in some way. An obvious perturbation is to introduce mass and in out universe most of the mass comes from dark matter. So most likely the virtual particles of our universe that make up the vacuum energy comes from dark matter.
Lets see if I can find a paper. Here it is "Phenomenology of Effective Gravity" by Volovik from Finland but in English as all physics papers are. I got the abstract but not a link. I cannot get you a link without losing this text. So ask again if you are interested.
Phenomenology of effective gravity
Author: G.E. Volovik
Comments: LaTeX file, 25 pages, no figures, prepared for proceedings of the COSLAB school in Krakow, 2002; some issues are clarified, references are added
The cosmological constant is not an absolute constant. The gravitating part of the vacuum energy is adjusted to the energy density of matter and to other types of the perturbations of the vacuum. We discuss how the vacuum energy responds (i) to the curvature of space in the Einstein closed Universe; (ii) to the expansion rate in the de Sitter Universe; and (iii) to the rotation in the Goedel Universe. In all these steady state Universes, the gravitating vacuum energy is zero in the absence of the perturbation, and is proportional to the energy density of perturbation. This is in a full agreement with the thermodynamic Gibbs-Duhem relation applicable to any quantum vacuum. It demonstrates that (i) the cosmological constant is not huge, since according to the Gibbs-Duhem relation the contribution of zero point fluctuations to the vacuum energy is cancelled by the trans-Planckian degrees of freedom; (ii) the cosmological constant is non-zero, since the perturbations of the vacuum state induce the non-zero vacuum energy; and (iii) the gravitating vacuum energy is on the order of the energy density of matter and/or of other perturbations. We also consider the vacuum response to the non-steady-state perturbations. In this case the Einstein equations are modified to include the non-covariant corrections, which are responsible for the relaxation of the cosmological constant. The connection to the quintessence is demonstrated.