Inhomogeneous post-inflationary Lambda-CDM cosmology as a moduli space
  expansion
  We model the large scale late time universe as a Lambda-CDM cosmology driven
by cosmological constant and perfect dust fluid. Our aim is to find new
solutions in the matter and Lambda epoch consistent with inflationary initial
conditions, namely that to the far past in the matter era the cosmology tends
to a flat FLRW solution. We identify the moduli degrees of freedom that
parametrize the flat Lambda-dust FLRW solution and then promote these moduli to
slowly varying functions of the spatial coordinates and show how to solve the
Einstein equations in a comoving gradient expansion, controlled by the
cosmological constant length scale. Our initial conditions ensure that the
approximation remains under control to the far past of the matter era, and to
the far future of Lambda domination. The solution is fully non-perturbative in
the amplitude of the metric deformation, and we explicitly construct it to
fourth order in derivatives. A general Lambda-dust universe dominated by Lambda
in the future is characterized by a 3-metric and a stress tensor (with positive
trace) defined on the future conformal boundary. The new cosmologies with
inflationary initial conditions are characterized only by the boundary
3-metric, the stress tensor being locally determined entirely in terms of that
metric.
