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Naty1

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the divergent big bang singularity into a finite big crunch...

If so, what changed and is this a generally accepted 'new start' at the front end of the FLRW model which follows??

I may have missed some discussions in November/December as I was away,

but I did skim this discussion from that time frame:

Penrose's argument that q.g. can't remove the Big Bang singularity

https://www.physicsforums.com/showthread.php?t=649836From that discussion, papers linked to by Marcus were discussed, so I read them and was surprised to find this in the Introduction:

An Extension of the Quantum Theory of Cosmological

Perturbations to the Planck Era

Ivan Agullo, Abhay Ashtekar, William Nelson

http://arxiv.org/pdf/1211.1354v1.pdf

...the FLRW space-times of interest are invariably incomplete in the past

due to the big bang singularity where matter ﬁelds and space-time curvature diverge...

... to encompass the Planck regime, one needs a quantum gravity extension of

the standard cosmological perturbation theory. ...Loop quantum gravity (LQG) provides a promising avenue to meet this goal because by nowin a variety of models in LQC. It is therefore natural to use LQC as the point of departure for extending the cosmological perturbation theory.the big bang singularity has been resolved

Can someone explain what has been 'resolved'?

From the other paper by the same authors,

A Quantum Gravity Extension of the Inflationary Scenario

Ivan Agullo, Abhay Ashtekar, William Nelson

(Submitted on 7 Sep 2012)

http://arxiv.org/abs/1209.1609

the early text says this:

In layman's terms, did truncating [the author's term] continuous spacetime somehow eliminate the associated divergences??...Since the standard inflationary paradigm is based on quantum field theory on classical space-times, it excludes the Planck era... Using techniques from loop quantum gravity, the paradigm is extended to a self-consistent theory from the Planck scale to the onset of slow roll inflation, ...Loop quantum gravity (LQG) oﬀers a natural framework to address these issues because eﬀects of its underlying quantum geometry dominate at the Planck scale…The key diﬀerence from standard inﬂation is that quantum ﬁelds … now propagate on a quantum geometry represented by Ψo (a, φ) rather than on a classical Friedmann solution (a(t), φ(t)).Thus, by construction, the framework encompasses the Planck regime…., we use the conceptual framework of quantum ﬁeld theory on cosmological quantum geometriesThese quantum geometries are all regular, free of singularities.