What is the origin of spatial inhomogeneities in the Universe?

In summary, during the formation of inhomogeneities, all fields existed in a vacuum state with no real particles, only virtual ones. The inflaton, non-vacuum state, slowly slid down and transferred energy to the fields, exciting them and creating clumps of real particles in the places of fluctuations. These clumps continued to expand, resulting in nonzero density variations. During reheating at the end of inflation, the inflaton field decayed rapidly into standard model particles, causing slight differences in field values to result in different densities.
  • #1
sergiokapone
302
17
We get the following picture of the formation of inhomogeneities:

Initially, all eternally existing fields (possibly fermionic-lepton-quark-DM-field and GUT-field) lived in a vacuum state --- no real particles (only virtual ones), just fluctuated (##\left\langle\Delta E\right\rangle = 0##, ##\left\langle\Delta E^2\right\rangle \neq 0## ). And there was an inflaton, far from being in a vacuum state (why would? Others in a vacuum). Passing into a vacuum state (slowly sliding down as Linde wants), the inflaton transferred energy to the fields (somehow excited them) and born particles clumbs in places of fluctuation, but still expanding along the way - these clumps of real particles were stretched, but new clumps still continued to be born in those places where the fields fluctuated with the extraction of energy from the inflaton. We obtained nonzero ##\Delta\rho/\rho## at different scales, and it was these inhomogeneities in real particles in space (not virtual) that were further condensed due to gravity into clusters, galaxies, stars ...? So I understand?
 
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  • #2
I don't think it's a matter of the inflaton transferring energy to other fields. The energy in other fields was driven rapidly to zero by inflation. Rather, as the universe expanded and the inflaton approached its potential energy minimum, the value of the inflaton field itself fluctuated, descending slightly faster in some regions than in others.

When it reached its minimum, the inflaton field decayed rapidly into standard model particles (reheating). The very slight differences in the field value from place to place due to the initial fuctuations result in different densities once reheating is finished.
 
  • #3
kimbyd said:
I don't think it's a matter of the inflaton transferring energy to other fields.
At the end of inflation, it is, as you say later in your post:

kimbyd said:
When it reached its minimum, the inflaton field decayed rapidly into standard model particles (reheating)
I think the key thing the OP appears not to have grasped here is that reheating is not a continuous process that goes on during inflation; it is a very rapid process that happens at the end of inflation.
 

Related to What is the origin of spatial inhomogeneities in the Universe?

What is the origin of spatial inhomogeneities in the Universe?

The origin of spatial inhomogeneities in the Universe is a complex and ongoing topic of study in cosmology. It refers to the uneven distribution of matter and energy throughout the Universe, which can be observed on both large and small scales.

How do we observe and measure spatial inhomogeneities in the Universe?

Scientists use a variety of methods and tools to observe and measure spatial inhomogeneities in the Universe. These include telescopes, satellites, and computer simulations. By studying the distribution of galaxies, clusters of galaxies, and the cosmic microwave background radiation, we can gain insights into the structure and evolution of the Universe.

What causes spatial inhomogeneities in the Universe?

There are several theories that attempt to explain the origin of spatial inhomogeneities in the Universe. One of the leading theories is inflation, which proposes that the Universe underwent a rapid expansion in its early stages, leading to the formation of small density fluctuations that eventually grew into the large-scale structures we observe today.

Are spatial inhomogeneities the same throughout the Universe?

No, spatial inhomogeneities vary in different regions of the Universe. This is due to the fact that matter and energy are not evenly distributed, and their distribution is affected by various factors such as gravity, dark matter, and dark energy. Therefore, the level of inhomogeneity can vary from one region to another.

What implications do spatial inhomogeneities have for our understanding of the Universe?

The study of spatial inhomogeneities in the Universe has significant implications for our understanding of the origin, evolution, and future of the Universe. By studying these structures, we can gain insights into the fundamental laws of physics, the nature of dark matter and dark energy, and the fate of the Universe. It also helps us to better understand the formation and evolution of galaxies and other cosmic structures.

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