Invisible QCD as Dark Energy
  We account for the late time acceleration of the Universe by extending the
QCD color to a $SU(3)$ invisible sector (IQCD). If the Invisible Chiral
symmetry is broken in the early universe, a condensate of dark pions (dpions)
and dark gluons (dgluons) forms. The condensate naturally forms due to strong
dynamics similar to the Nambu--Jona-Lasinio mechanism. As the Universe evolves
from early times to present times the interaction energy between the dgluon and
dpion condensate dominates with a negative pressure equation of state and
causes late time acceleration. We conclude with a stability analysis of the
coupled perturbations of the dark pions and dark gluons.
