Verlinde, LQG, entropy and gravity as a fundamental force vs emergent

In summary: I have seen in the context of this paper)Actually I am surprised that I have not read of more applications of holographic reasoning in the past. For example, if you assume that the universe is a computer, then the holographic principle is trivially true, since the information content of the universe is finite. So if you cannot store more information than is inside, it follows that you can describe the universe by much less information than the full information content.
  • #36
MTd2 said:
Gravity makes me think about mass. But mass is not an issue here, but entropy. Entropy is not quantized, but is a consequence of quantization. So, the only thing left here to quantize is geometry and the fields that lives on it.
(quasi-local) mass is a very difficult and derived concept in GR ...
 
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  • #37
I don't get what you are saying.
 
  • #38
quasi-local mass is a derived concept in GR that is not completely understood; you don't need it for the dynamics of gravity; all you need is energy-momentum density
 
  • #39
But energy tensor ends up involving point masses anyway, which will end up in geometry controlled by mass terms.
 
  • #40
MTd2 said:
But energy tensor ends up involving point masses anyway, which will end up in geometry controlled by mass terms.
No, it doesn't. Mass means integrating a voluem form which is tricky in curved spacetime. Forget about mass. It's not an energy tensor, it's an energy-momentumdensity tensor.
 
  • #41
Density is still a mass term.
 
  • #42
Formally the Einstein equations tell you that the action of an operator containing purely geometric degrees of freedom equates to something containing other (= "matter") degrees of freedom. If you want to separate geometry and gravity you have to make sense of "quantized geometry" alone = w/o taking into account the dynamics of the matter degrees of freedom = w/o taking into account dynamics. But I don't know how to separate geometry from dynamics b/c both have the same origin; that's one lesson of GR.
 
  • #43
Hmm, I guess what I am arguing here is the nature of matter after all. The concept is so weird that I got confused.
 

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