Pixelated Dark Energy
  We study the phenomenology of a recent string construction with a quantum
mechanically stable dark energy. A mild supersymmetry protects the vacuum
energy but also allows $O(10 - 100)$ TeV scale superpartner masses. The
construction is holographic in the sense that the 4D spacetime is generated
from "pixels" originating from five-branes wrapped over metastable five-cycles
of the compactification. The cosmological constant scales as $\Lambda \sim 1/N$
in the pixel number. An instability in the construction leads to cosmic
expansion. This also causes more five-branes to wind up in the geometry,
leading to a slowly decreasing cosmological constant which we interpret as an
epoch of inflation followed by (pre-)heating when a rare event occurs in which
the number of pixels increases by an order one fraction. The sudden appearance
of radiation triggers an exponential increase in the number of pixels. Dark
energy has a time varying equation of state with $w_a=-3\Omega_{m,0}(1+w_0)/2$,
which is compatible with current bounds, and could be constrained further by
future data releases. The pixelated nature of the Universe also implies a
large-$l$ cutoff on the angular power spectrum of cosmological observables with
$l_{\rm max} \sim O(N)$. We also use this pixel description to study the
thermodynamics of de Sitter space, finding rough agreement with effective field
theory considerations.
