Based on the string theory concept of holography, Hawking and Hertog now postulate that
https://phys.org/news/2018-05-multiversestephen-hawking-theory-big.html
https://www.sciencealert.com/stephen-hawking-s-last-physics-paper-theory-on-eternal-inflation-multiverses
https://arxiv.org/abs/1707.07702
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https://vimeo.com/267131639
In their new paper, Hawking and Hertog say this account of eternal inflation as a theory of the big bang is wrong. "The problem with the usual account of eternal inflation is that it assumes an existing background universe that evolves according to Einstein's theory of general relativity and treats the quantum effects as small fluctuations around this," said Hertog. "However, the dynamics of eternal inflation wipes out the separation between classical and quantum physics. As a consequence, Einstein's theory breaks down in eternal inflation."
"We predict that our universe, on the largest scales, is reasonably smooth and globally finite. So it is not a fractal structure," said Hawking.
Their results, if confirmed by further work, would have far-reaching implications for the multiverse paradigm. "We are not down to a single, unique universe, but our findings imply a significant reduction of the multiverse, to a much smaller range of possible universes," said Hawking.
https://phys.org/news/2018-05-multiversestephen-hawking-theory-big.html
https://www.sciencealert.com/stephen-hawking-s-last-physics-paper-theory-on-eternal-inflation-multiverses
https://arxiv.org/abs/1707.07702
[video=vimeo;267131639]https://vimeo.com/267131639[/video]
https://vimeo.com/267131639