Exact Classical Correspondence in Quantum Cosmology?

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Discussion Overview

The discussion revolves around a paper claiming to find a solution to the Wheeler-DeWitt equation that corresponds to classical evolution in a Friedmann model. Participants explore implications of this model, particularly regarding the universe's expansion after the inflationary epoch and its relation to primordial nucleosynthesis and the cosmic microwave background (CMB).

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants highlight the paper's claim of a coasting universe post-inflation, suggesting it is an attractive problem worth pursuing.
  • Others express skepticism about the model's compatibility with primordial nucleosynthesis observations, indicating potential issues with the proposed timeline of the universe's evolution.
  • There is a suggestion that alternative approaches and 'toy models' may provide insights, even if they do not immediately align with all observations.
  • One participant raises a speculative question about the relationship between the LHC's primordial conditions and the early universe, prompting a clarification about the energy scales involved.
  • Another participant notes that the discussion contributes to the plausibility of a non-accelerating universe in the current epoch.

Areas of Agreement / Disagreement

Participants express differing views on the validity of the proposed model, particularly regarding its implications for established observations like primordial nucleosynthesis. The discussion remains unresolved with multiple competing perspectives on the model's applicability.

Contextual Notes

Participants note limitations in the model's consideration of the CMB and nucleosynthesis, suggesting that further work is needed to reconcile these aspects with the proposed theory.

Garth
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A paper published in 'Gravitation and Cosmology', [21, 208 (2015)] and on today's physics ArXiv claims to have found a solution to the Wheeler-DeWitt equation that exactly corresponds to the classical evolution of a Friedmann model with appropriate matter/energy density: Exact Classical Correspondence in Quantum Cosmology, interestingly it states:
It is of particular interest to note that for the open case in this scenario, after the inflationary epoch, the universe enters a coasting evolution
a ∝ t and continues to expand in this fashion. The spontaneous creation of the coasting universe obtained in the present paper from nothing is an attractive problem worth pursuing.

Garth
 
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Garth said:
A paper published in 'Gravitation and Cosmology', [21, 208 (2015)] and on today's physics ArXiv claims to have found a solution to the Wheeler-DeWitt equation that exactly corresponds to the classical evolution of a Friedmann model with appropriate matter/energy density: Exact Classical Correspondence in Quantum Cosmology, interestingly it states:

Garth
After the inflationary era? Pretty sure that would run afoul of primordial nucleosynthesis observations.
 
Chalnoth said:
After the inflationary era? Pretty sure that would run afoul of primordial nucleosynthesis observations.
Yes, he doesn't look at the CMB - or nucleosynthesis for that matter - perhaps there is work to be done on this model!

To be explicit, it is important to try alternative approaches in tentative 'toy models' that may not be able immediately to explain all observations, while explaining others, because they may be modified into a concordant model at a later date.

Garth
 
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If the time was NOW and THEN, could it be true that LHC's primordial soup is the one that was in the beginning? What if we are in the beginning and the end?
 
Alex Kostko said:
If the time was NOW and THEN, could it be true that LHC's primordial soup is the one that was in the beginning? What if we are in the beginning and the end?
Hi Alex and welcome to these Forums!

However you will have to rephrase your question so that it makes sense - I can't tell whether you are 'coming or going'!

The LHC, although it does attain the highest energies/temperatures anywhere seen on Earth - especially under laboratory conditions - is nowhere near as energetic as the Inflation era.

Inflation is thought to take place from about t ~ 10-36 until 10-33-10-32 seconds after the 'BB' when the energy scale was around 1016 GeV or 10−3 times the Planck energy. By contrast the present enhanced LHC is capable of around 14 Tev or 14 x 103 GeV - some 12 orders of magnitude less.

Garth
 
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Right, Garth, another interesting piece of work gradualy adding plausibility to a non-accelerating universe in the present epoch.
 
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