Constraining Entropic Cosmology
  It has been recently proposed that the interpretation of gravity as an
emergent, entropic force might have nontrivial implications to cosmology. Here
two approaches are investigated: in one, the Friedman equation receives
entropic contributions from the usually neglected surface terms, and in
another, the extra terms are derived from quantum corrections to the entropy
formula. UV terms may drive inflation, avoiding a recently derived no-go
theorem, though in some cases leading to a graceful exit problem. IR terms can
generate dark energy, alleviating the cosmological constant problem. The
quantum corrections are bounded by their implications to the BBN, and the
surface terms are constrained in addition by their effect upon the behavior of
matter. Likelihood analyses are performed to constrain the modifications by the
SNeIa, BAO and CMB data. It is found that a monomial correction to the
area-entropy formula results in late acceleration in very good agreement with
observations, which then turn out to be compatible with positive curvature. The
evolution of perturbations is deduced by assuming the Jebsen-Birkhoff theorem.
Distinct signatures can then be identified in the large scale structure
formation. Furthermore, it is shown that the visible universe satisfies the
Bekenstein bound.
