Rovelli & Vidotto's Planck Stars describes a possible quantum black hole - white hole transition through a quantum bounce somewhat analogous to the LQC bounce.(adsbygoogle = window.adsbygoogle || []).push({});

In another thread, @marcus pointed out to me that this was not necessarilly considered the most likely scenario for a QG black hole.

Is this not however in a way, qualitatively, an almost unavoidable scenario in quantum gravity?

If I understand it correctly, the GR black hole in Kruskal coordinates already describes a pair (BH, WH) joined by a singularity at r=0, with a metric $$ds^2=\frac{4k}{r}e^{-\frac{r}{k}}(-dT^2+dX^2)+r^2d\Omega^2$$

If quantum gravity (or any modification to GR at high density) resolves the singularity, and assuming an effective spacetime description remains possible near the singularity, as seems to be the case in LQC, one would expect this to be replaced by an effective metric of a form more or less similar to $$ds^2=\frac{4k}{\phi(r)}e^{-\frac{r}{k}}(-dT^2+dX^2)+\phi(r)^2d\Omega^2$$where ##\phi(r)\sim r\text{ for }r\gg r_{min}\text{ but }\phi(0)>0##.

But then it would seem that this naturally extends to the whole Kruskal solution and must be describing the type of scenario explored in the above reference?

Is this too simplistic, or are the assumptions above too strong? What am I missing here?

Thanks

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# Planck Stars and GR black and white holes

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