Information entropy and dark energy evolution
  The information entropy is here investigated in the context of early and late
cosmology under the hypothesis that distinct phases of universe evolution are
entangled between them. The approach is based on the \emph{entangled state
ansatz}, representing a coarse-grained definition of primordial \emph{dark
temperature} associated to an \emph{effective entangled energy density}. The
dark temperature definition comes from assuming either Von Neumann or linear
entropy as sources of cosmological thermodynamics. We interpret the involved
information entropies by means of probabilities of forming structures during
cosmic evolution. Following this recipe, we propose that quantum entropy is
simply associated to the thermodynamical entropy and we investigate the
consequences of our approach using the adiabatic sound speed. As byproducts, we
analyze two phases of universe evolution: the late and early stages. To do so,
we first recover that dark energy reduces to a pure cosmological constant, as
zero-order entanglement contribution, and second that inflation is
well-described by means of an effective potential. In both cases, we infer
numerical limits which are compatible with current observations.
