Small dark energy without small parameters
  We present a prototype model that resolves the cosmological constant problem
using matter alone, i.e., without modifying gravity. Its generic cosmological
solutions adjust an arbitrarily large, negative dark energy to a positive value
parametrically suppressed by an initial field velocity. Inflationary initial
conditions lead to a positive dark energy exponentially smaller in magnitude
than any model parameter, or any scale in the initial conditions.
