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High Energy Phenomenology Seminar: Tom Banks (Rutgers) "Density Matrix of Causal Diamonds and a Finite Model of the Very Early Universe"

Event Type
Department of Physics
wifi event
Oct 14, 2022   11:00 am  
Tom Banks (Rutgers)
Brandy Koebbe

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.

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