Is Galilean Creation a Viable Alternative to Inflationary Cosmology?

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Discussion Overview

The discussion centers on the viability of Galilean creation as an alternative to inflationary cosmology. Participants explore theoretical implications, potential models, and the challenges associated with superluminal excitations within this framework.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants introduce Galilean creation as a proposed alternative to inflationary cosmology, referencing a paper that suggests a smooth transition to single field inflation.
  • One participant requests a more accessible explanation of Galilean creation, indicating difficulty in understanding the referenced paper.
  • Another participant points to a different paper on Galilean Genesis, noting that it requires superluminal excitations, which raises concerns about its viability.
  • Some participants express skepticism about the necessity of superluminal excitations in the Galilean Genesis model, while others argue that the model's conclusions suggest they might be unavoidable.
  • There is a mention of historical context regarding Galileo, with a participant suggesting that his explanations were cautious to avoid conflict with authorities.
  • One participant agrees that unresolved issues surrounding superluminal excitations could undermine the model's credibility, although they note that later papers may address these concerns.
  • Another participant claims that a different model, studied earlier, does not lead to superluminal propagation, suggesting it as a potentially more viable alternative.

Areas of Agreement / Disagreement

Participants express differing views on the implications of superluminal excitations within the Galilean Genesis model. While some believe these excitations are problematic, others argue they may not be unavoidable. The discussion remains unresolved regarding the overall viability of Galilean creation compared to inflationary cosmology.

Contextual Notes

Participants highlight the dependence on specific assumptions regarding superluminal excitations and the interpretations of various models. There are references to multiple papers, indicating a complex landscape of theoretical exploration without consensus on the implications of these findings.

Chronos
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Galilean creation is one of a number of proposed alternatives to inflationary cosmology. This paper; http://arxiv.org/abs/1504.05710, Galilean Creation of the Inflationary Universe, takes the idea a step further by showing how it can transit smoothly to the single field inflationary model favored by WMAP and Planck.
 
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Got a decent link explaining the basics of Galilean Creation? The paper is just a tad beyond my understanding.
 
Chronos said:
See http://arxiv.org/abs/1007.0027, Galilean Genesis: an alternative to inflation.
Hmm. Apparently this model requires superluminal excitations. That makes it seem rather unlikely.
 
Galilieo was probably trying to explain things in a manner which would not irritate the inquisitors too much.
 
rootone said:
Galilieo was probably trying to explain things in a manner which would not irritate the inquisitors too much.
This is a different idea. It's a recent alternative to inflation that relies upon a big rip-like scenario.
 
Superluminal excitations are discussed, but, not deemed unavoidable under the Galilean Genesis model.
 
Chronos said:
Superluminal excitations are discussed, but, not deemed unavoidable under the Galilean Genesis model.
Sounded like they were pretty unavoidable to me. If you read the last paragraph in their conclusion, they basically say, "Well, maybe they can be avoided. We don't know how, but maybe."
 
I agree, if the superluminal issue cannot be resolved, the model is suspect. Later papers appear promising on this count.
 
  • #10
That's a nice idea, except that it had been suggested and studied thoroughly 6 months earlier in

http://inspirehep.net/record/1320024

(this model does not lead to superluminal propagation)
 

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