Cosmological constant problem, interesting solution?

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Discussion Overview

The discussion centers on potential solutions to the cosmological constant problem, exploring various theoretical approaches and models. Participants share links to papers and reports that propose different mechanisms or frameworks related to the cosmological constant and dark energy.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • Some participants reference a paper suggesting a solution to the cosmological constant problem, noting its calculation yields a cutoff-scale near the Planck scale using two scalar fields.
  • Another participant introduces an alternative perspective, discussing a model that posits the universe began with a "big melt" rather than a "big bang," linking to a detailed paper on this idea.
  • A further contribution highlights Christof Wetterich's approach, which employs a quantum effective action and describes the Planck mass as a scalar field, suggesting that inflation and dark energy are manifestations of the same underlying process. The participant expresses skepticism about the model's claims of compatibility with current cosmological observations.

Areas of Agreement / Disagreement

Participants present multiple competing views and models regarding the cosmological constant problem, with no consensus reached on the validity or acceptance of any particular approach.

Contextual Notes

Some claims depend on specific interpretations of scalar fields and the nature of dark energy, and there are unresolved questions regarding the implications of the proposed models on current cosmological observations.

windy miller
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Som news outlets are reporting a potential solution to the cosmological constant problem:
https://arxiv.org/pdf/1703.00543.pdf
opinions on this paper are much appreciated.
 
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Space news on Phys.org
Here is a report from the university

It is interesting that their calculation (based on the observed cosmological constant) gives a cutoff-scale that is not too far away from the Planck scale. They just used two scalar fields, a more realistic field content would be interesting.
 
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Here is a very interesting way of arriving at the cosmological constant.

http://nautil.us/issue/53/monsters/the-universe-began-with-a-big-melt-not-a-big-bang

A more detailed paper: https://arxiv.org/abs/1703.06144

regards
sunu
 
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What do you think of Christof Wetterichs way? He uses a quantum effective action to describe the Universe (as a transition between fixed points of RG flow) where the Planck mass is described as a scalar field ("variable gravity"). This model (where masses decrease in time and the Universe shrinks) incorporates very naturally dark energy. See e.g. https://arxiv.org/pdf/1705.00552.pdf (one in a series of many papers on this model). As far as I understand it, in his model inflation and DE are just two manifestations of the same. He also claims that his model is compatible with all current observations in cosmology, but I'm not really convinced yet.
 

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