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is this the starting point of a new cosmology ? (lemmy.world)
submitted 4 months ago* (last edited 4 months ago) by A_A@lemmy.world to c/askscience@lemmy.world
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Hi,

I found this scientific paper that I believe is very well supported and is for me the most satisfying new cosmological development I ever read.

Cosmological Particle Production: A Review
(2021 December 7 // @ arXiv...)
https://arxiv.org/pdf/2112.02444.pdf

... the way I read it, it provides an alternative explanation for the cosmological microwave background (CMB) and an alternative for the Big Bang.

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[–] count_of_monte_carlo@lemmy.world 20 points 4 months ago (1 children)

There isn’t a link in your post, but it looks like you’re referring to this preprint. The article has been published in a peer reviewed journal paywall warning.

This is a review article, so it isn’t proposing anything new and is instead giving a summary of the current state of the field. These sorts of articles are typically written by someone who is deeply familiar with the subject. They’re also super useful if you’re learning about a new area - think of them as a short, relatively up-to-date textbook.

I’m not sure how you’re interpreting this review as an alternative to the standard model of cosmology and the Big Bang. Everything is pretty standard quantum field theory. The only mention of the CMB is in regards to the possibility that gravitons in the early universe would leave detectable signatures (anisotropies and polarization). They aren’t proposing an alternative production mechanism for the CMB.

[–] Mbourgon@lemmy.world 8 points 4 months ago (1 children)

How can you tell it’s a review? That sounds like an easy way to learn about a subject’s state-of-the-art, and I’d like to find more.

[–] count_of_monte_carlo@lemmy.world 16 points 4 months ago (1 children)

Haha it’s in the title: “Cosmological Particle Production: A Review”. Also the journal it was published in is for review articles: Reports on Progress in Physics. Mostly though the abstract promises to give a review of the subject.

Another indication is its lengthy (28 pages) with tons of citations throughout. If someone is doing new work, citations will mostly be in the introduction and discussion sections.

[–] Mbourgon@lemmy.world 9 points 4 months ago

Okay, I’m denser than the subjects discussed in it. Thanks for the detailed explanation, it’s appreciated.

[–] A_A@lemmy.world 3 points 4 months ago

i only have access to the preprint :
https://arxiv.org/pdf/2112.02444.pdf

[–] A_A@lemmy.world -1 points 4 months ago (1 children)

i cannot understand everything (far from it) but here is the part where I believe is an alternative explanation for the CMB :

Equations (2.38), (2.39), (2.40), and (2.53) all illustrate that the creation rate of particles with energies larger than the inverse expansion time, ρ, is exponentially suppressed. Parker [11] has noted that these exponential factor are similar to those which appear in thermal spectrum at finite temperature.

[–] count_of_monte_carlo@lemmy.world 10 points 4 months ago (1 children)

So unfortunately the article they reference by Parker is paywalled. I have access but can’t share it easily. The article is essentially the foundation of quantum field theory in curved space time - in other words the genesis of the standard cosmological model. Cosmological particle production in an expanding universe isn’t an alternative to the Big Bang, it’s an essential part of it.

Leonard Parker’s work is summarized on his Wikipedia page. You can also read an interview with him on the arxiv

[–] A_A@lemmy.world -2 points 4 months ago (1 children)

Thanks for your input.

May I take another route and ask you what you know about the history of science ... about paradigm shifts ... and about how people very knowledgeable on the current paradigm cannot see (most of times historicaly) that a paradigm shift is about to happen ?

[–] count_of_monte_carlo@lemmy.world 1 points 4 months ago (1 children)

how people very knowledgeable on the current paradigm cannot see (most of times historicaly) that a paradigm shift is about to happen ?

I’m not sure I’d agree with that assessment. Generally a new model or understanding of physics arises because of known shortcomings in the current model. Quantum physics is the classic example that resolved a number of open problems at the time: the ultraviolet catastrophe in black body radiation, the photoelectric effect, and the interference pattern of the double slit experiment, among others. In the years leading up to the development of quantum theory, it was clear to everyone active in physics that something was missing from the current understanding of Newtonian/classical physics. Obviously it wasn’t clear what the solution was until it came about, but it was obvious that a shift was coming.

The same thing happened again with electroweak unification%20and%20the%20weak%20interaction.) and the standard model of particle physics. There were known problems with the previous standard model Lagrangian, but it took a unique mathematical approach to resolve many of them.

Generally research focuses on things that are unknown or can’t be explained by our current understanding of physics. The review article you linked, for example, details open questions and contradictory observations/predictions in the state of the art.

[–] A_A@lemmy.world 4 points 4 months ago (1 children)

Thanks again for your time and consideration.

We are discussing here in a community dedicated to science and clearly I have to acknowledge that your arguments here are much better than mine 😆 and that you are very knowledgeable in the current paradigm of science.

Unfortunately for me, there is no community at Lemmy dedicated to the history of science where "very knowledgeable on the current paradigm" would be so telling for historians knowledgeable in this field.

[–] count_of_monte_carlo@lemmy.world 5 points 4 months ago (1 children)

Unfortunately for me, there is no community at Lemmy dedicated to the history of science

I agree! The history of science is often even more interesting since you get both the science and the personalities of all the people involved, plus the occasional world war in the mix. It’s a shame there isn’t an “askhistorians” type community here.

[–] threelonmusketeers@sh.itjust.works 3 points 4 months ago

there is no community at Lemmy dedicated to the history of science

That seems like something @Sal@mander.xyz might be able to fix...