I'll summarize recent work on the density matrices of generic causal diamonds, and apply it to construct a model of inflation, reheating, baryogenesis and dark matter. General ideas about incorporating causality in quantum gravity show that a theory of inflation that avoids the Trans Planckian problems of field theory, leads to a post inflationary universe dominated by a dilute gas of black holes. Black hole decay leads to the Hot Big Bang and gives a roughly correct value for the baryon-antibaryon asymmetry. It can fit current data on the CMB, but gives different expectations for tensor fluctuations and non-Gaussian features of the spectrum. The most attractive model for dark matter assumes a discrete gauge symmetry whose lightest charged state is a Planck mass black hole remnant. Assuming 10^{-8} - 10^{-9} of the decaying black holes carry this charge, we fit the crossover point of matter and radiation densities in the observed universe. The model also contains a spectrum of meta-stable black holes, formed by mergers of the initial "inflationary black holes" before they decay. It's hard to calculate the mass spectrum of these meta-stable black holes, but they could contribute a fraction of decaying dark matter, which could lead to observational signals, or rule the model out.
