Effective Cosmological Constant and Dark Energy
  Two very different methods are used to estimate the magnitude of the
effective cosmological constant / dark energy (for the present cosmic epoch).
Their results agree with each other and are in agreement with observations. One
method makes use of unimodular gravity and causal set theory, while the other
one employs arguments involving spacetime foam and holography. I also motivate
and discuss the possibility that quanta of (both) dark energy (and dark matter
in the Modified Dark Matter model) are extended/non-local, obeying infinite
statistics, also known as quantum Boltzmann statistics. Such quanta out-number
ordinary particles obeying Bose-Einstein or Fermi-Dirac statistics by a factor
of $\sim 10^{30}$.
