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• CommentRowNumber1.
• CommentAuthorUrs
• CommentTimeJul 13th 2018

started something. For the moment really just a glorified pointer to Buchert et al. 15 and putting Scharf 13 into perspective

• CommentRowNumber2.
• CommentAuthorUrs
• CommentTimeJul 13th 2018

typo fixed

• CommentRowNumber3.
• CommentAuthorUrs
• CommentTimeJul 14th 2018
• (edited Jul 14th 2018)

expanded a bit more and introduced subsections.

found a useful conclusion of the arguments exchanged in the “backreaction debate”, in Ostrowski-Roukema 15, and added it as a quote (here)

• CommentRowNumber4.
• CommentAuthorUrs
• CommentTimeJul 16th 2018

further added various bit of this and that, notably some quotes on the qualitative understanding of how inhomogeneity may give rise to accelerated expansion (here). That was fun, but I should leave it at that now.

• CommentRowNumber5.
• CommentAuthorUrs
• CommentTimeJul 24th 2018

added pointer to Coley 18, p. 28, where it is confirmed that it remains open whether cosmic inhomogeneity may have substantial backreaction on cosmic evolution (in view of the debate about a claim by Green-Wald to the contrary)

• CommentRowNumber6.
• CommentAuthorUrs
• CommentTimeAug 2nd 2018
• (edited Aug 2nd 2018)

This is remarkable, as they claim an analytic solution exhibiting the effect:

Our analysis is based on the discovery of a closed ansatz for perturbations of the SM during the p$= 0$ epoch of the Big Bang which triggers instabilities that create unexpectedly large regions of accelerated uniform expansion within Einstein’s original theory without the cosmological constant. We prove that these accelerated regions introduce precisely the same range of corrections to redshift vs luminosity as are produced by the cosmological constant in the theory of Dark Energy.

• CommentRowNumber7.
• CommentAuthorDavidRoberts
• CommentTimeAug 3rd 2018

Cool!

• CommentRowNumber8.
• CommentAuthorUrs
• CommentTimeAug 3rd 2018
• (edited Aug 3rd 2018)

Should this hold water, and dark energy shown to be just an artifact of an inappropriate model, this would be the most dramatic triumph of rigour over handwaving in physics. Cosmology/HEP physics has entered an era of storytelling since the last decades, and this might well be what brings mathematical physics back to the forefront.

• CommentRowNumber9.
• CommentAuthorUrs
• CommentTimeMay 8th 2019

• Zhiqi Huang, Han Gao, Haoting Xu, Revisiting Ryskin’s Model of Cosmic Acceleration (arXiv:1905.02441)
• CommentRowNumber10.
• CommentAuthorUrs
• CommentTimeMay 8th 2019

also added a brief quote from their article

at the end of the section “The backreaction debate” (here)

• CommentRowNumber11.
• CommentAuthorUrs
• CommentTimeSep 7th 2019