Inflationary Theory out of thin air?

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Discussion Overview

The discussion revolves around inflationary theory in cosmology, particularly its implications for the early universe and the horizon problem. Participants explore the theoretical underpinnings of inflation, its observational evidence, and the relationship between inflation and other cosmological models, such as the cyclic universe. The conversation includes technical aspects of cosmic expansion and the implications of various models on our understanding of the universe's evolution.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • Some participants question the evidence supporting inflationary theory, suggesting it may be more theoretical than observational.
  • Others argue that inflation addresses the horizon problem by proposing rapid expansion during the early universe.
  • There is a discussion about the implications of the speed of light (C) in relation to the expansion of space, with some asserting that regions of space can expand faster than C without violating relativity.
  • One participant mentions that the predictions of inflation, such as the distribution of matter and the spectral slope, are supported by observations like the Cosmic Microwave Background (CMB) and large-scale structure.
  • Another participant notes that the predictions of inflation are also consistent with alternative models, such as Dr. Steinhardt's cyclic universe, highlighting the need for definitive evidence like B-mode polarization in the CMB to distinguish between them.
  • There is a debate about the nature of recessional velocities and how they relate to redshift, with some emphasizing the role of general relativity in understanding these phenomena.
  • Participants express differing views on the implications of B-mode polarization, with some claiming it would support inflation and contradict the cyclic universe, while others suggest it could be interpreted differently.
  • A participant proposes a theory linking the Higgs mechanism and vacuum energy to the universe's expansion dynamics, raising questions about the timing of changes in vacuum energy density.

Areas of Agreement / Disagreement

Participants express a range of views on inflationary theory, its evidence, and its implications, with no clear consensus reached. Disagreements persist regarding the interpretation of observational data and the validity of competing models.

Contextual Notes

Participants reference various models and theories, including the Friedmann equations and the implications of general relativity, without resolving the complexities involved in these discussions. The conversation includes assumptions about the nature of cosmic expansion and the role of different cosmological models.

  • #31
FunkyDwarf said:
Its a good point, like i said I am simply reiterating what I've read. As i see it though they weren't really one force as such, rather they were grouped together because under the conditions of the time they all acted the same. As these conditions changed so the forces that decoupled exibited different behaviours and effects, thus affecting the world around them in a way that affected the overall entropy.
As I understand it, the other forces diverged from the one force through some mechanism of symmetry breaking. And I've suggested that h-bar was larger during inflation when the forces were one. So I have to further wonder if the required symmetry breaking process could be accomplished by a reduction of h-bar. Since h-bar has the units of an action, a larger h-bar argues for more invariance in the action integral. If the minimum possible action is larger, then changes in the action integral with respect to variables within it will still be within that minimal amount of h-bar and thus not noticed. So if the minimal possibe action becomes smaller, then invariances will have a more noticeable change in the action integral, and previous symmetries may disappear. Any thought on this anyone? Thanks.
 
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  • #32
The problem I see mike2 is a scaling h parameter is irrelevant prior to the emergence of spacetime - assuming spacetime is emergent. Albeit might be a factor in a background dependent model. BTW, I have a link you might find interesting:

Probability Theories with Dynamic Causal Structure: A New Framework for Quantum Gravity
http://arxiv.org/abs/gr-qc/0509120
 
  • #33
Chronos said:
The problem I see mike2 is a scaling h parameter is irrelevant prior to the emergence of spacetime - assuming spacetime is emergent. Albeit might be a factor in a background dependent model. BTW, I have a link you might find interesting:

Probability Theories with Dynamic Causal Structure: A New Framework for Quantum Gravity
http://arxiv.org/abs/gr-qc/0509120
What do you suppose spacetime emerges from?

From what I can gather, h-bar shows that space and time are related in a spinfoam type QFT to matter and energy. The delta-energy*delta-time>h-bar indicates time (a spacetime property) in relation to energy (a particle property), whereas the delta-momentum*delta-position>h-bar indicates space (a spacetime property) in relation to mometum (a particle property). So it seems spacetime is inexerably connected to vacuum energy (virtual particles).

If h-bar were zero it seems spacetime would be exactly correlated with energy-momentum. But if h-bar were larger, then expansion (of spacetime) would not be well correlated with vacuum energy (virtual particle properties).
 
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  • #34
A universe from nothing would be my guess.
 

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