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How can inflation homogenize an inhomogeneous distribution of massive particles in the early universe if it increases all distances between the particles with the same factor?

If the inflation caused the particles, when sufficiently far apart,* to recede from each other at superluminal velocities, then when the inflation stops, do they keep receding from each other with the velocity they acquired due to the acceleration during the inflation, only slowed down only by a very weak gravity? I fail to see how their relative -superluminal- velocity at the end of the inflation can decrease to a velocity below she speed of light -which they must if they are to re-enter each other's each other's observation horizon again. *And what, by the way, would be 'sufficiently far apart,’ 1 mm, 1 lightyear?

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In inflationary cosmology Standard Model particles are created after inflation, during the reheating stage when inflaton oscillates around the minimum of the potential, and subsequently decays into ordinary matter.

On the other hand, small inhomogeneities (or fluctuations) of the inflaton are indeed streched out by inflation, contributing to the effective potential in the corresponding area. Those stretched fluctuations can themselves form separate visible universes, or "bubbles" in the bubble universe.

Particles are not technically moving with the expansion of space. That's why superluminal expansion is OK. You can visualize it as good old inflating balloon, where its surface represents our space. Then it becomes clear that particles you "glue" to the surface are not moving.

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  • $\begingroup$ Comments are not for extended discussion; this conversation has been moved to chat. $\endgroup$
    – ACuriousMind
    Commented May 9, 2017 at 10:28

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