  An effective quantum field theory (QFT) with a manifest UV/IR connection, so
as to be valid for arbitrarily large volumes, can successfully be applied to
the cosmological dark energy problem as well as the cosmological constant (CC)
problem. Motivated by recent approaches to the hierarchy problem, we develop
such a framework with a large number of particle species. When applying to
systems on the brink of experiencing a sudden collapse to a black hole, we find
that the entropy, unlike the total energy, now becomes an increasing function
of the number of field species. An internal consistency of the theory is then
used to infer the upper bound on the number of particle species, showing
consistency with the holographic Bekenstein-Hawking bound. This may thus serve
to fill in a large gap in entropy of any non-black hole configuration of matter
and the black holes. In addition, when the bound is saturated the entanglement
entropy matches the black hole entropy, thus solving the multiplicity of
species problem. In a cosmological setting, the maximum allowable number of
species becomes a function of cosmological time, reaching its minimal value in
a low-entropy post-reheating epoch.

General Relativity and Quantum Cosmology;High Energy Physics - Phenomenology;High Energy Physics - Theory