How Likely are Constituent Quanta to Initiate Inflation?

Abstract

We propose an intuitive framework for studying the problem of initial conditions in slow-roll inflation. In particular, we consider a universe at high, but sub-Planckian energy density and analyze the circumstances under which it is plausible for it to become dominated by inflated patches at late times, without appealing to the idea of self-reproduction. Our approach is based on defining a prior probability distribution for the constituent quanta of the pre-inflationary universe. To test the idea that inflation can begin under very generic circumstances, we make specific -- yet quite general and well grounded -- assumptions on the prior distribution. As a result, we are led to the conclusion that the probability for a given region to ignite inflation at sub-Planckian densities is extremely small. Furthermore, if one chooses to use the enormous volume factor that inflation yields as an appropriate measure, we find that the regions of the universe which started inflating at densities below the self-reproductive threshold nevertheless occupy a negligible physical volume in the present universe as compared to those domains that have never inflated.

13 pages

References in corpus (5)

• The Measure Problem in Cosmology
• The Classical Universes of the No-Boundary Quantum State
• Inflationary schism after Planck2013
• Measure and Probability in Cosmology
• Classical Inflationary and Ekpyrotic Universes in the No-Boundary Wavefunction

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