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Reality Divides

#1
Ostronomos Offline
Here we see that reality can divide itself.

Theoretical physics: The origins of space and time
https://www.nature.com/news/theoretical-...me-1.13613

EXCERPT: . . . Meanwhile, Van Raamsdonk has proposed a very different idea about the emergence of space-time, based on the holographic principle. Inspired by the hologram-like way that black holes store all their entropy at the surface, this principle was first given an explicit mathematical form by Juan Maldacena, a string theorist at the Institute of Advanced Study in Princeton, New Jersey, who published his influential model of a holographic universe in 1998. In that model, the three-dimensional interior of the universe contains strings and black holes governed only by gravity, whereas its two-dimensional boundary contains elementary particles and fields that obey ordinary quantum laws without gravity.

Hypothetical residents of the three-dimensional space would never see this boundary, because it would be infinitely far away. But that does not affect the mathematics: anything happening in the three-dimensional universe can be described equally well by equations in the two-dimensional boundary, and vice versa.

In 2010, Van Raamsdonk studied what that means when quantum particles on the boundary are 'entangled' — meaning that measurements made on one inevitably affect the other. He discovered that if every particle entanglement between two separate regions of the boundary is steadily reduced to zero, so that the quantum links between the two disappear, the three-dimensional space responds by gradually dividing itself like a splitting cell, until the last, thin connection between the two halves snaps. Repeating that process will subdivide the three-dimensional space again and again, while the two-dimensional boundary stays connected. So, in effect, Van Raamsdonk concluded, the three-dimensional universe is being held together by quantum entanglement on the boundary — which means that in some sense, quantum entanglement and space-time are the same thing.
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#2
C C Offline
(Jun 25, 2018 02:10 PM)Ostronomos Wrote: https://www.nature.com/news/theoretical-...me-1.13613 [...] whereas its two-dimensional boundary contains elementary particles and fields that obey ordinary quantum laws without gravity. [...]


Yep, two. Hardly sounds like full-blown pregeometry yet. (MORE: Is physics legislated by cosmogony? ... Geometry, pregeometry and beyond)

Such placeholder "building blocks" which Rovelli speculates about below wouldn't actually be interpenetrating each other in a dimensionless "point", since the latter is a geometric element itself whose descriptive identity is made possible by comparison with extended, extrinsic conditions that permit more degrees of freedom. What it would be instead is something size-less and scale / relation independent (neither tiny nor large, similar to Leibniz's classic, immaterial monads). These supposed "quanta piled together in _X_" would lack location because they would be the prior-in-rank provenance which made attributes like "residing or existing somewhere and somewhen" possible in the first place.

Tim Folger, about Carlo Rovelli: These would be the building blocks of space and time. It’s not easy to imagine space and time being made of something else. Where would the components of space and time exist, if not in space and time? As Rovelli explains it, in quantum mechanics all particles of matter and energy can also be described as waves. And waves have an unusual property: An infinite number of them can exist in the same location. If time and space are one day shown to consist of quanta, the quanta could all exist piled together in a single dimensionless point. “Space and time in some sense melt in this picture,” says Rovelli. “There is no space anymore. There are just quanta kind of living on top of one another without being immersed in a space.” --Newsflash: Time May Not Exist ... Discover Mag ... June, 2007


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