When exactly did 'quantum fluctuations' in the early universe occur?

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Discussion Overview

The discussion centers around the timing of quantum fluctuations in the early universe, particularly in relation to density fluctuations and their potential connection to dark matter. Participants explore various theoretical frameworks, including supersymmetry and primordial black holes, while seeking clarity on the consensus regarding these phenomena.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant references a video summarizing a paper from the University of Tokyo, seeking clarification on when density fluctuations are believed to have occurred in the early universe and their implications for dark matter.
  • Another participant mentions that while they are unfamiliar with the specific field discussed in the paper, they suggest that density fluctuations may have occurred around ##10^{-32}## seconds after the Big Bang, linking this to theories involving sterile neutrinos as a candidate for dark matter.
  • A later post humorously reflects on the complexity of the type 2 seesaw mechanism related to the MSSM Higgs, indicating a need for further investigation.
  • Additional contributions provide links to external articles discussing primordial black holes and their potential role in dark matter, while noting the lack of evidence for such black holes and questioning the mechanisms by which they could form from the Big Bang.
  • One participant asserts that physicists generally do not support the idea that dark matter consists of black holes, highlighting the ongoing debate in the community.

Areas of Agreement / Disagreement

Participants express differing views on the timing of quantum fluctuations and the nature of dark matter, with no consensus reached on these topics. The discussion reflects multiple competing theories and uncertainties surrounding these concepts.

Contextual Notes

Participants acknowledge the complexity of the theories discussed, including the dependence on definitions and the unresolved nature of certain mathematical steps related to the timing of fluctuations and dark matter candidates.

MJM
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TL;DR
A recent paper by Kawasaki and Murai discuss how quantum fluctuations could've led to primordial black holes, which eventually became the supermassive black holes we see today.
I came across this video today:

Which summarizes this new paper from University of Tokyo: https://arxiv.org/pdf/1907.02273.pdf

I get that the video is just an explainer for primordial black holes, but I was hoping to get a better explanation on exactly when conventional wisdom says density fluctuations occurred in the early universe. And what's the consensus on whether or not this can help explain dark matter?
 
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While I am unfamiliar with the AD field in this paper, which utilizes super symmetry (MSSM) in order to time with inflation estimates were looking at roughly ##10^{-32}## seconds.
No one knows what DM is for sure, however under MSSM treatments involving the Higgs field it's possible that DM may be sterile neutrinos which would form shortly after inflation with electro weak symmetry breaking (inflation itself may have be caused by EWSB) however this is just one theory among many.
Just a hunch but this reminds me of a type 2 seesaw mechanism involved in the paper. I would have to dig deeper to confirm that though
 
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Lol the reminder due to similarities of type 2 seesaw under MSSM Higgs/Higglets is about as far as that went ...
Glad I checked lmao
 
https://en.m.wikipedia.org/wiki/Primordial_black_hole

https://www.skyandtelescope.com/astronomy-news/black-holes/could-dark-matter-be-black-holes/

So far there is no evidence of such black holes existing, though the Sky and Telescope article above brings up one candidate.

The Wikipedia article lists observational bounds for the mass and the abundance of primordial black holes.

There is no obvious mechanism how the Big Bang would create mini black holes.

https://www.sciencemag.org/news/2017/02/dark-matter-made-black-holes

It looks like physicists do not believe that dark matter consists of black holes.
 

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