  This paper deals with the thermodynamic properties of a phantom field in a
flat Friedmann-Robertson-Walker universe. General expressions for the
temperature and entropy of a general dark-energy field with equation of state
$p=\omega\rho$ are derived from which we have deduced that, whereas the
temperature of a cosmic phantom fluid ($\omega<-1$) is definite negative, its
entropy is always positive. We interpret that result in terms of the intrinsic
quantum nature of the phantom field and apply it to (i) attain a consistent
explanation for some recent results concerning the evolution of black holes
which,induced by accreting phantom energy, gradually loss their mass to finally
vanish exactly at the big rip, and (ii) introduce the concept of cosmological
information and its relation with life and the anthropic principle. Some
quantum statistical-thermodynamic properties of the quantum quantum field are
also considered that include a generalized Wien law and the prediction of some
novel phenomena such as the stimulated absorption of phantom energy and the
anti-laser effect.
