An exact model of conformal quintessence
  A non--minimally coupled quintessence model is investigated and the conditions for a stationary solution to the coincidence problem are obtained. For a conformally coupled scalar field and dissipative matter, a general solution possessing late acceleration is found. It fits rather well the high redshift supernovae data and gives a good prediction of the age of the Universe. Likewise, the cold dark matter component dominates the cosmological perturbations at late times albeit they decrease with expansion. 
Luis P. Chimento, Alejandro S. Jakubi and Diego Pavon