Ok no more sniping. So Quantum Loop Gravity theory includes white holes not just as wormholes but within the same universe as a bounce effect where a black hole reaches a critical mass and then rewinds and becomes a white hole.
Here, Francesca Vidotto shares thoughts on it from London, Ontario, where she teaches physics at The University of Western Ontario:
”One fundamental property of the loop quantum gravity theory is that it allows for black holes to transition into white holes, which are the opposites of black holes, spitting out matter and energy, as opposed to consuming everything.
Oh, well, yes. The fundamental property is the fact that space-time is quantized, where you have fundamental grains of space-time. But this also has a counterpart, the fact that curvature is bounded. This means that the singularities that appear in general relativity are resolved in a quantum theory of gravity. Applied to the early universe, in cosmology there is a big bounce. The same thing happens in the center of a black hole.
Instead of having a singularity in the center, we just have a region that is very, very dense. When such a high density is reached, an effective quantum force appears like a repulsion that prevents the collapse of the black hole from continuing and triggers a new expanding phase that corresponds to a white hole. The idea that you can have a transition from a black hole to a white hole was something explored in the past, in the form of the Einstein-Rosen bridge [aka wormhole]. But the idea was that you would end up being in another region of space-time.
The insight that changes the picture is the possibility to have a transition to a white hole within our universe. Imagine you have some matter that starts collapsing, gets more and more dense, and in the process turns it into the very compact object that is a black hole. Then it reaches the maximal density and also a core of minimum size. At that point it starts to expand back, it’s as if you were seeing a movie in rewind, and everything starts expanding in the form of an explosion. If you can have things exploding back, this can also provide a possible window to search for quantum gravity, and we can look for traces of such an explosion.”
daily.jstor.org/francesca-vidotto-the-quantum-properties-of-space-time/
In this theory, they solve the problem of Big Bang Theory which violates the conservation of energy law by positing that the Big Bang was actually a large white hole. (I put that in layman’s terms in my first post).