  We propose a model of inflation driven by the relaxation of an initially
Planckian cosmological constant due to diffusion. The model can solve the
horizon and flatness problem, and generate a (approximately) scale invariant
spectrum of (adiabatic) primordial perturbations with the correct amplitudes
and blue tilt without an inflaton. The inhomogeneities observable in the CMB
arise from those associated to the fundamental Planckian granularity that are
imprinted into the standard model Higgs scalar fluctuations during the
inflationary phase. The process admits a semiclassical interpretation and
avoids the trans-Planckian problem of standard inflationary scenarios based on
the role of vacuum fluctuations. The deviations from scale invariance observed
in the CMB are controlled by known parameters of the standard model of particle
physics. If an order one portion of these fluctuations collapses to form
primordial black holes the model produces the amount of cold dark matter
required by observations.
