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Tuesday, September 2, 2014

Reality Emergent

CAUTION: In what follows, your mind could be blown!

Image Credit: C. Hogan, Fermilab
Related source » Fermilab | Holometer | Holometer FAQ: 'via Blog this'
[This related source is recommended in its entirety.]

How is holographic noise different from space-time foam?

John Wheeler's vision of quantum space-time was a roiling foam of virtual black holes. It was based on extrapolation of quantum field theory to the Planck scale. The holographic view is that space-time is not quantized like other fields, but emerges from a quantum system with fewer degrees of freedom than field theory. If this is right, foam is not the right way to visualize the smallest scales.

What do you mean by emergent space-time?

In general, we say that a property is "emergent" when it is obvious at large scales, even though it does not exist on smaller scale. Here is an example. The color of a wall is a large scale property. The color of the entire wall is the same as the color of individual drops of paint. However, when we get to a very small scale, the idea of "color" does not work. The color we see depends on how the fundamental particles (electrons, neutrons, and protons) are arranged. But each of these fundamental particles does not have a color.

Similarly, we can say that space-time itself is "emergent" from a fundamentally quantum system. On large scales [it] looks like what we are used to. However, on small scales the concepts of position do not exist. This happens at about the level of the Planck length. The concept of time does not exist for intervals shorter than the Planck time. This fundamental quantum system "looks like" classical spacetime in a macroscopic limit.
— Last modified: 06/07/2013 (

In my very humble opinion, the implication of this endeavor is that reality, as we perceive it, emerges from Plank-scale black-hole "evaporation" (i.e., disappearing with a pop of energy release). I think my mind just popped (but how could I know that?).

Help — I can't find my head!
Post 2,381 Reality Emergent

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