Why aren't Gravitational waves factored in to inflation formulas?

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Discussion Overview

The discussion revolves around the role of gravitational waves in inflationary physics, questioning why they are not typically included in inflation models. Participants explore the implications of gravitational waves on the inflation rate curve and their potential connection to dark matter, while also addressing the nature of the scalar field involved in inflation.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • Some participants propose that gravitational waves might be overlooked in inflationary models, suggesting their potential significance in understanding inflation dynamics.
  • Others argue that inflation inherently smooths out any gravitational waves present, implying they do not contribute significantly to inflationary dynamics.
  • A participant questions the notion of a completely homogeneous universe during inflation, suggesting that clumps of matter must have existed, which contradicts the idea that inflation smooths everything out.
  • Concerns are raised about the observational confirmation of the scalar field used in inflation models, with some suggesting it is more mathematically derived than empirically validated.
  • There is a discussion about the relationship between dark matter and inflation, with some asserting that dark matter is a separate topic that arises after inflation ends.
  • One participant expresses frustration at the perceived harshness of responses, emphasizing the importance of accommodating laypersons in scientific discussions.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the role of gravitational waves in inflation. Multiple competing views remain regarding the implications of gravitational waves, the nature of the scalar field, and the relationship between inflation and dark matter.

Contextual Notes

There are unresolved questions about the assumptions underlying the smoothness of the universe during inflation and the observational status of the scalar field. The discussion also highlights differing interpretations of the relationship between inflation and the subsequent formation of matter.

Barque
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TL;DR
Layman, asking question which seems intuitive. Gravitational waves ought likely be factored in to inflation mathematics.
It seems to me that gravitational waves are ignored when inflationary physics are described. I'm not very well read, and honestly do not know so much about most of the physics going on with inflation. Still, wave mechanics matter, harmonics matter, and it just seems intuitive to me that in order to get such a whacky inflation rate curve, something isn't being considered. Is it possible that the harmonics associated with huge masses of energy crashing together might help? Would something like this have anything to do with dark matter?

thanks for accommodating a layperson, it's a simple premise really but it seems ignored: gravitational waves as a part of inflation
 
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Barque said:
It seems to me that gravitational waves are ignored when inflationary physics are described.
That's because, heuristically, inflation "smooths" any "bumps" in curvature, and that includes gravitational waves. So gravitational waves, if they happened to be present when inflation started, would quickly get smoothed out and would not contribute anything significant to the dynamics.

Barque said:
in order to get such a whacky inflation rate curve
What do you mean by this? Inflation is a simple consequence of a particular kind of scalar field; there's nothing at all "whacky" about it.

Barque said:
Is it possible that the harmonics associated with huge masses of energy crashing together might help?
What "huge masses of energy crashing together" are you talking about? During inflation there is nothing else in the universe.

Barque said:
Would something like this have anything to do with dark matter?
Dark matter is a completely different topic from inflation. Which one do you want to talk about?
 
Doesn't this reply connote a certain denial of "clumps" of matter? Certainly, things were not all smoothed out? Something smells bad here, but again - I don't really do this work for a living.
PeterDonis said:
That's because, heuristically, inflation "smooths" any "bumps" in curvature, and that includes gravitational waves. So gravitational waves, if they happened to be present when inflation started, would quickly get smoothed out and would not contribute anything significant to the dynamics.What do you mean by this? Inflation is a simple consequence of a particular kind of scalar field; there's nothing at all "whacky" about it.What "huge masses of energy crashing together" are you talking about? During inflation there is nothing else in the universe.Dark matter is a completely different topic from inflation. Which one do you want to talk about?
Also, the scalar field you speak of seems to be more mathematically derived than observationally confirmed. We make scales, physics might not really be in accordance even when appearing to do so.

huge masses of energy crashing together. if things were all homogenous then there wouldn't be clumps? Again, I'm a primitive here - was simply curious.

If dark matter and inflation are not intertwined then someone is missing the point - all mass was distributed.

My question was about gravitational effects during inflation - beyond constants. It simply seems that masses (clumps) bashing together early makes waves. These waves interact, and if at proper frequencies, they harmonize.

Again, I'm no mathematician, and the poke seemed harsh to me. Then again I can accept stepping into a new public forum and being forced to face my own ignorance. Lol... can you bother to accommodate a layperson?
 
meh, was question. there are 8 billion people here and some think they are smart. Even if you are average there are 4 billion people smarter than you. without a safe community, however, nobody goes anywhere.
 
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Barque said:
Doesn't this reply connote a certain denial of "clumps" of matter? Certainly, things were not all smoothed out?
Evidently you didn't grasp what "during inflation there is nothing else in the universe" means. Inflation happens before there is any matter. What you call "matter" gets created when inflation ends, and all the energy that was stored in the scalar field gets transferred to the usual Standard Model fields we know--quarks, leptons, etc. During inflation the scalar field is the only thing there is, and it doesn't clump.

Barque said:
the scalar field you speak of seems to be more mathematically derived than observationally confirmed.
The Higgs field is a scalar field. Not the same one as the one that appears in inflation models, but the fact remains that we do have observational evidence that scalar fields in general can exist.

Barque said:
We make scales
"Scales" has nothing to do with a scalar field. "Scalar" means "zero spin".

Barque said:
huge masses of energy crashing together. if things were all homogenous then there wouldn't be clumps?
See my response to the first quote above.

Barque said:
all mass was distributed.
There is no "mass" in the sense you mean the term during inflation; there is no matter in the universe. See my response to the first quote above.

Barque said:
My question was about gravitational effects during inflation
No, your question was about gravitational waves during inflation.

If you want to talk about gravitational "effects" more generally, inflation is a gravitational effect--it's the gravitational effect of a scalar field when it's the only field in the universe that contains any energy.

Barque said:
I'm a primitive here
Barque said:
I'm no mathematician
Given these admissions of yours, you should have a very low level of confidence in your ability to come up with correct intuitive answers about how inflation works.

Barque said:
and the poke seemed harsh to me
What poke?

Barque said:
can you bother to accommodate a layperson?
I am accommodating you: I'm explaining why your intuition about inflation is wrong. What else would you expect?
 
Barque said:
meh, was question. there are 8 billion people here and some think they are smart. Even if you are average there are 4 billion people smarter than you. without a safe community, however, nobody goes anywhere.
What is your point here?
 
You win the thread dude, have fun!
 
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Barque said:
You win the thread dude, have fun!
It's not a matter of winning or losing. Is your question answered or not? If it is, good. If it isn't, responding with snark accomplishes nothing.
 
@Barque - are you confusing inflation, a theory about the early universe, with the expansion we see today? They're related phenomena (kind of) but they aren't the same thing.
 
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I ask because you mention dark matter, which has nothing to do with inflation (as Peter says, it forms as part of the process when inflation ends) but does affect the dynamics of expansion and the "clumping" of galaxy formation.
 
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