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How does a multiverse get its mass/energy? + Information without particle exchange

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C C Offline
In a Mind-Bending New Paper, Physicists Give Schrodinger's Cat a Cheshire Grin
https://www.sciencealert.com/schrodinger...s-analysis

INTRO: "I've often seen a cat without a grin," thought Alice. "But a grin without a cat! It's the most curious thing I ever saw in all my life!"

It's an experience eminent physicist Yakir Aharonov can relate to. Together with fellow Israeli physicist Daniel Rohrlich, he's shown theoretically how a particle might show its face in a corner of an experiment without needing its body anywhere in sight.

To be more precise, their analysis argues information could be transferred between two points without an exchange of particles. The theory dates back to 2013 when researchers based in the US and Saudi Arabia suggested a kind of freezing effect applied to a quantum wave still might not be enough to stop it from transmitting information.

"We found it extremely interesting – the possibility of communication without anything passing between the two people who communicate with each other," Aharonov explained to Anna Demming at Phys.org. "And we wanted to see if we can understand it better."

The experimental model they base their calculations on is surprisingly simple... (MORE - details)


How do we get enough mass to have a multiverse?
https://www.forbes.com/sites/startswitha...ultiverse/

EXCERPTS (Ethan Siegel): One of the predictions arising from those too-early-for-confirmation times is that our Universe is just one of many, with the sum total of everything making up a multiverse. But where does all the mass/energy for a multiverse come from? [...] This is an incredibly deep question, and the best answer we can give is full of surprises.

[...] If inflation is also a quantum field — which it ought to be, considering that everything in the Universe is (probably) fundamentally quantum in nature — that means it experiences quantum fluctuations. ... that means there are some “pockets” of the inflationary Universe where inflation ends earlier, others where it ends later, and still others where it must still be ongoing, even today.

[...] Wherever inflation comes to an end — no matter how big or small the region is where that happens, no matter where or when it occurs, and no matter whether the regions surrounding it are still inflating or not — you get a hot Big Bang and a new chance at a Universe like ours. There’s a lot we don’t know, even in theory, about these multiple Universes, but if inflation is correct and the laws of physics that we know are still valid during it, their existence is all but inevitable. This is where the idea of the multiverse, from a pure physics perspective (with no appeals to philosophy, interpretations of quantum mechanics, or assumptions about the pre-inflationary Universe), arises from.

[...] given this remarkable story, you might rightly worry exactly what we’ve been asked this week, “where did the energy for all of this come from?”

Here’s where things are really going to go against your intuition. You’ve no doubt heard about the law of conservation of energy: that energy can never be created nor destroyed, only transformed from one form into another. [...] But for the entire Universe itself — or for a spacetime in general — energy isn’t always conserved, or even well-defined. Energy can only be well-defined if you’re in a static spacetime: one that’s the same, overall, from one moment to the next...

Both normal matter and dark matter, for example, are made of particles: they have a specific mass and occupy a specific volume. As the Universe expands, the number of particles stays the same, the volume increases, but the total energy remains the same.

Radiation, however, is different. Light waves have an energy that’s defined by their wavelength, where shorter wavelengths mean higher energies and longer wavelengths mean lower energies. As the Universe expands, the number of quanta of radiation stays the same, but the wavelength gets stretched to longer distances, causing each quantum to lose energy. As time goes on and the volume increases, the total energy drops.

Dark energy is also different. It’s an energy inherent to the fabric of space itself: a form of energy that has a small value today, but had a very large value during inflation. As space expands, the energy density remains constant, but the volume increases. The total energy of the Universe goes up over time, since energy equals density multiplied by volume.

This is unsatisfying to many, but it’s the truth: energy is neither conserved nor even well-defined for a Universe whose space expands or contracts over time. If you like, you can force energy to be conserved by imposing a global definition of energy: one where you can draw a boundary around a portion of the Universe and demand “energy must be conserved in here.” The only way to do it is to add in another definition: of work done on the boundary you drew as the Universe expands. Radiation does positive work, and that’s why it loses energy; dark energy (or inflationary energy) does negative work, and that’s why the total energy goes up.

As attractive as that imposition is, however, it isn’t a sound definition. It’s something we can simply choose to do — incorrectly, mind you — solely to fit our prejudice that energy must be conserved. The fact is that energy conservation only works at a particular location, not for the expanding Universe.

You might have heard the expression that “there’s no such thing as a free lunch.” While that might be true here on Earth, that reasoning doesn’t apply to the expanding Universe. In fact, if ideas like inflation and the multiverse are correct, perhaps the real truth is that the Universe is the ultimate free lunch. In these trying times, this is one thing we can all be thankful for... (MORE - details, illustrations)
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