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Clues about holographic universe + Crunching multiverse to solve 2 puzzles at once - C C - Jan 13, 2022
Crunching multiverse to solve two physics puzzles at once
https://phys.org/news/2022-01-crunching-multiverse-physics-puzzles.html
EXCERPT: . . . In broad brushes, the duo's theory works like this. In its early moments, the universe is a collection of many universes each with a different value of the Higgs mass, and in some of these universes the Higgs boson is light. In this multiverse model, universes in which the Higgs boson is heavy collapse in a big crunch in a very short time, whereas universes in which the boson is light survive this collapse. Our present-day universe would be one of these surviving light-Higgs universes... (MORE - missing details)
Symmetries reveal clues about the Holographic Universe
https://www.quantamagazine.org/symmetries-reveal-clues-about-the-holographic-universe-20220112/
EXCERPTS: While the other three forces of nature are all due to the activity of quantum fields, our best theory of gravity describes it as bent space-time. For decades, physicists have tried to use quantum field theories to describe gravity, but those efforts are incomplete at best.
One of the most promising of those efforts treats gravity as something like a hologram — a three-dimensional effect that pops out of a flat, two-dimensional surface. Currently, the only concrete example of such a theory is the AdS/CFT correspondence [...] In the bizarre curves of AdS space, a finite boundary can encapsulate an infinite world. Juan Maldacena, the theory’s discoverer, has called it a “universe in a bottle.”
But our universe isn’t a bottle. Our universe is (largely) flat. Any bottle that would contain our flat universe would have to be infinitely far away in space and time. Physicists call this cosmic capsule the “celestial sphere.”
Physicists want to determine the rules for a CFT that can give rise to gravity in a world without the curves of AdS space. They’re looking for a CFT for flat space — a celestial CFT.
The celestial CFT would be even more ambitious than the corresponding theory in AdS/CFT. Since it lives on a sphere of infinite radius, concepts of space and time break down. As a consequence, the CFT wouldn’t depend on space and time; instead, it could explain how space and time come to be.
Recent research results have given physicists hope that they’re on the right track. These results use fundamental symmetries to constrain what this CFT might look like. [...] “There’s a very large, amazing animal out here,” said Nima Arkani-Hamed, a theoretical physicist at the Institute for Advanced Study in Princeton, New Jersey. “The thing we’re going to find is going to be pretty mind-blowing, hopefully.”
[...] When you have a theory that applies to an infinitely distant sphere, problems arise. Consider two particles that come together and scatter apart. If they scatter apart at any nonzero angle, by the time they reach the infinitely distant celestial sphere, they will also be infinitely far apart. The notion of distance breaks down. Our normal theories rely on locality, in which the strength of interactions between objects depends on their distance from one another. But if everything is infinitely far from everything else, the CFT must transcend locality.
Even more perplexing: What is the concept of time on the celestial sphere, which is infinitely far in both the past and in the future? It has no meaning here.
Arkani-Hamed considers the fact that concepts of space and time break down on the celestial sphere to be a feature, not a bug. It offers the potential to explain space-time as an emergent property of a more fundamental theory... (MORE - missing details)
RE: Clues about holographic universe + Crunching multiverse to solve 2 puzzles at once - Syne - Jan 13, 2022
Postulating prematurely aborted universes to explain features of our own is not the least bit parsimonious.