How are inflaton particles that drive the early inflation created?

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Discussion Overview

The discussion centers around the creation of inflaton particles that drive the early inflation of the universe, exploring the potential energy of inflaton fields and the role of fundamental forces during this period. Participants examine the implications of inflation on the standard model of particle physics and the energy scales involved, including the relationship between inflation and gravitational waves.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose that normal matter is created only after inflation stops, suggesting that inflaton particles may be produced by non-standard model processes.
  • Others argue that the inflation period is part of the electro-weak epoch, indicating that gravity and the strong force were present during inflation.
  • A later reply questions the validity of GUT-scale and SUGRA-based models of inflation, seeking references to support these claims.
  • Some participants discuss the uncertainty surrounding the energy scale of inflation, with references to presentations that depict a range of possible values.
  • One participant mentions that the energy scale of inflation is observable through tensor perturbations in the CMB, citing Planck constraints on the tensor/scalar ratio.
  • There is a suggestion that the inflation energy scale should be at or above the GUT scale, reflecting differing views on the implications of the inflationary epoch.
  • Participants inquire about references explaining how gravitational waves cause tensor perturbations of the CMB background, indicating a desire for further technical understanding.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the presence of fundamental forces during inflation and the energy scales involved. The discussion remains unresolved, with no consensus on the implications of these theories.

Contextual Notes

Limitations include the dependence on definitions of inflationary models and the uncertainty in the energy scale of inflation, as well as unresolved questions about the processes that create inflaton particles.

Dilatino
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Assuming that the early inflation of the universe is driven by the potential energy of some inflaton field(s), the "normal" matter is created only after this rapid inflation has stopped by conversion of the latent energy of the corresponding phase transition to particles.

Does this mean that the 3 fundamental forces and the corresponding particles summerized in the standard model of particle physics were not yet present during the inflation and even earlier, such that the inflaton particles themself have to be created exclusively by non SM processes?

What are the assumed processes and interactions that are capable of producing the inflaton particles themself?
 
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Welcome to PF;
The inflation period itself, in Big Bang cosmology, forms the first part of the electro-weak epoch. i.e. gravity and the strong force have separated out. i.e. these forces were present during inflation.
 
Simon Bridge said:
Welcome to PF;
The inflation period itself, in Big Bang cosmology, forms the first part of the electro-weak epoch. i.e. gravity and the strong force have separated out. i.e. these forces were present during inflation.
Do you have a reference for this? Have GUT-scale and other SUGRA-based models of inflation been somehow ruled out?
 
Simon Bridge said:
Welcome to PF;
The inflation period itself, in Big Bang cosmology, forms the first part of the electro-weak epoch. i.e. gravity and the strong force have separated out. i.e. these forces were present during inflation.

Looking at this presentation (slide 19), the energy scale at which the inflation period occurs is depicted as having a large uncertainty. Is there any evidence to suggest that it was actually nearer the electroweak scale (the bottom end of the range shown) rather than higher, in BSM land?
 
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sheaf said:
Looking at this presentation (slide 19), the energy scale at which the inflation period occurs is depicted as having a large uncertainty. Is there any evidence to suggest that it was actually nearer the electroweak scale (the bottom end of the range shown) rather than higher, in BSM land?
Right, that's what I'm getting at. The energy scale of inflation is only observable through the presence of tensor perturbations in the CMB generated by primordial gravitational waves. The amplitude of tensors is commonly given in terms of the tensor/scalar ratio: the latest Planck constraints give r<0.1 at 95% CL. The slow roll approximation gives
V_0^{1/4} \sim \left(\frac{r}{0.7}\right)^{1/4}\times 1.8 \times 10^{16}\, {\rm GeV}
where V_0 is the vacuum energy density of inflation when the observed perturbations were generated -- this is the energy scale of inflation. With the Planck bound on r, we get V_0^{1/4} \lesssim 10^{16}\,{\rm GeV}, well above the electroweak scale.
 
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bapowell said:
Do you have a reference for this?
Pretty much any sophomore physics text dealing with the subject has it on it's timeline for the Big Bang as "inflationary epoch".
This may or may not be what was intended but I'm not going to get more sophisticated than that unless I have to :)

Have GUT-scale and other SUGRA-based models of inflation been somehow ruled out?
Not to my knowledge.
I figured I'd wait before writing a textbook ;)

You seem to be having fun though. Enjoy.
 
I started looking in this question a little after the Planck results came out earlier this year (I'm referring to the inflationary timeline stuff)... I remember being a little surprised by the lack of confidence voiced (I'm talking informally) from the physics community.

Anyway, I think I have some links stashed away from the episode--I'll edit them in if i can. (Then again if you wanted rigorous text-booky material you'll want bapowell or simon, but like I said i'll see what (if) I can find.)Speak of the devil: https://www.physicsforums.com/showthread.php?t=707029
 
Thanks for these comments, I rather thought too that the inlation energy scale should be at or above the GUT scale.

@Sheaf thanks for the link to the power point talk, this looks interesting

@bapowell is there some reference where it is explained how gravitational waves cause tensor perurbations of the CMB background?
 

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