# A connection between entropic gravity and the vacuum catastrophe ?

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Hello

If we take $\Large{\frac{1}{\Lambda}}$ for  the  "entropic surface" $A$ with this value of  $\Lambda=1.10242*10^{-52}m^{-2}$

The value of $N*8\pi$ from entropic gravity is exactly the value of the vacuum catastrophe (about $8.73^{122}$)  when $\Lambda=1.10242*10^{-52}m^{-2}$

Is that right and what physical meaning can it have please ?

Edited by stephaneww

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It's actually okay whatever the value of $A=\Large{\frac{1}{\Lambda}}$.

Edited by stephaneww

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oops, read : $8.73*10^{122}$ sorry

Edited by stephaneww

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Well, for greater clarity, with :

value of the vacuum catastrophe =

Energy Density of quantum mechanics / Energy Density of the comological constant =

$\Large {\frac {\frac{m_p c^2}{l_p^3}} {\frac{c^4 \Lambda}{8 \pi G}}}=$ (1)

$\Large {\frac {\frac{m_p}{l_p^2 l_p}} {\frac{c^2 \Lambda}{8 \pi G}}}=$ (2)

$\Large {\frac{m_p G}{l_p c^2}.\frac{8 \pi}{l_p^2 \Lambda}}=$ (3)

that can be simplified (with $m_p=\Large {\sqrt{\frac{c \hbar} {G}}}$ and $l_p=\Large {\sqrt{\frac{G \hbar} {c^3}}}$ )(4)

in $\Large {\frac{8 \pi} {l_p^2 \Lambda}}$ (5)

in the entropic gravity where the area $A=\Large {\frac{1} {\Lambda}}$

we have value of the vacuum catastrophe = $N. 8 \pi=\Large {\frac{8 \pi} {l_p^2 \Lambda}}$, cqfd

Edited by stephaneww

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Edited by stephaneww

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That although you can show certain relations that match. You are not digging deep enough into entropy gravity to find out where the contentions are with the standard model.

You will notice for example entropy gravity forms the basis behind MOND and in MOND the gravitational coupling constant will vary in different mass distributions so some of the relations above will also vary accordingly.

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Hi Mordred,

MOND is only one application.

there is also these one :

Quote

The theory claims to be consistent with both the macro-level observations of Newtonian gravity as well as Einstein's theory of general relativity and its gravitational distortion of spacetime. Importantly, the theory also explains (without invoking the existence of dark matter and its accompanying math featuring new free parameters that are tweaked to obtain the desired outcome) why galactic rotation curves differ from the profile expected with visible matter.

where I need to dig for the last case please ?

Edit :

Quote

According to reports in The Royal Astronomical Society magazine, the team of researchers led by Margot Brouwer tested Verlinde's theory by measuring the distribution of gravitational forces in a sample of 33,000 galaxies using the gravitational lens effect predicted by Einstein's theory of general relativity. They then discovered that by applying the calculations of Verlinde's theory of emergent gravity, they could achieve the same results without having to resort to the idea of dark matter. Thus, Einstein's theory of general relativity and Verlinde's theory of general relativity have the same relevance, at least in these measurements.

Edited by stephaneww

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If this was me I would start with the research papers on entropy gravity.

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the simplified transcription is on Wikipedia here

edit

I'm interested if you can find some more, of course.

Edited by stephaneww

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Here is a paper that better explains and argues against entropic gravity.

Hrrm so how do I put this.

The reason your seeing connections with the numerous formulas your using to those used in entropic gravity is simple yet fundamental.

F=ma the laws of inertia. All viable physics theories apply these laws of inertia. So every viable theory must at some point show that they are correctly applying these laws. This includes thermodynamics, relativity, (weak field limit), QM, QFT, string theory and the holographic principle.

Now this goes even deeper into what is called action. The action will correspond to the effective degrees of freedom which is how they are applying entropy though done through statistical mechanics (thermodynamics). The holographic principle is a methodology to reduce the number of degrees of freedom. That is where the holographic surface and the information contained in that surface comes into play.

Edited by Mordred

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Um, I don't know what to think: the paper is from 2010 (https://philpapers.org/rec/GAOWGI) before the successful cosmological test of 2016.

5 hours ago, Mordred said:

Hrrm so how do I put this.

The reason your seeing connections with the numerous formulas your using to those used in entropic gravity is simple yet fundamental.

F=ma the laws of inertia. All viable physics theories apply these laws of inertia. So every viable theory must at some point show that they are correctly applying these laws. This includes thermodynamics, relativity, (weak field limit), QM, QFT, string theory and the holographic principle.

Now this goes even deeper into what is called action. The action will correspond to the effective degrees of freedom which is how they are applying entropy though done through statistical mechanics (thermodynamics). The holographic principle is a methodology to reduce the number of degrees of freedom. That is where the holographic surface and the information contained in that surface comes into play.

I don't get the argument,  How is E.VERLINDE wrong ?

Edited by stephaneww

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Nothing in that statement suggests E.Verlinde is wrong. I am explaining that every physics theory will apply the above at some point.

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18 minutes ago, Mordred said:

Nothing in that statement suggests E.Verlinde is wrong. I am explaining that every physics theory will apply the above at some point.

ok ,thank you

edti :

17 hours ago, stephaneww said:

Is the novelty with entropic gravity that it gives meaning to the value of the vacuum catastrophe =N "=number of 'bits' of information"?

Edited by stephaneww

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The bits comply to quantum information theory but those bits would require quantization of gravity. Which hasnt happened yet. We have not successfully quantized gravity. In essence the theory above would require gravity to operate in discrete units (ie gravitons).

Edited by Mordred

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8 minutes ago, Mordred said:

We have not successfully quantized gravity.

is it possible ? I'm not sure because we have $G$ in $l_p^2$ in holographic approach ?

Edited by stephaneww

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QM requires quantization however relativity doesn't. It is this issue that prevents a successful theory of quantum gravity. More complex is how this applies to renormalization. Some physicist's feel that renormalization may be impossible while others feel the opposite.

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3 hours ago, Mordred said:

The bits comply to quantum information theory but those bits would require quantization of gravity. Which hasnt happened yet. We have not successfully quantized gravity. In essence the theory above would require gravity to operate in discrete units (ie gravitons).

3 hours ago, Mordred said:

QM requires quantization however relativity doesn't. It is this issue that prevents a successful theory of quantum gravity

It seems we can do without this quantification:

Quote

Les ondes sonores, par exemple, sont émergentes. Elles proviennent d’effets collectifs dans les molécules de l’air. Elles ne sont pas des phénomènes fondamentaux et, pour cette raison, il n’est par exemple pas envisagé de les quantifier. La connaissance du processus d’émergence change notre façon de comprendre le phénomène de façon non-triviale.

Quote

Sound waves, for example, are emergent. They come from collective effects in air molecules. They are not fundamental phenomena and, for this reason, it is for example not envisaged to quantify them. Knowledge of the emergence process changes our understanding of the phenomenon in a non-trivial way.

further on :

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… Mais la forme d’émergence particulière que je veux évoquer dans ce billet est différente. Elle est thermodynamique. La thermodynamique est une science qui montre que les propriétés d’un système physique constitué d’un grand nombre de petits éléments peuvent être comprises indépendamment des détails des constituants fondamentaux. C’est une science extraordinairement belle et fiable….

Quote

But the particular form of emergence I want to discuss in this post is different. It is thermodynamic. Thermodynamics is a science that shows that the properties of a physical system made up of a large number of small elements can be understood independently of the details of the fundamental constituents. It is an extraordinarily beautiful and reliable science.

from which further more the emerging gravity in the blog

Edited by stephaneww

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In the classical applications then yes renormalization isn't needed however quantum gravity does require quantization.

Sound waves for example using phonons under QM is renormalizable the phonon is the quantization. Phonons being a quasi particle.

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Quote

You can't extrapolate the notion of phonon directly into a gas.

I think that it is in this sense that Aurélien Barrau talks about sound waves :

Quote

Sound waves, for example, are emergent. They come from collective effects in air molecules.

... not in a crystal lattice ?

but here I'm entering territory I know nothing about.🙄

edit :

and the holographic principle (and entropic gravity) are phenomena coming from thermodynamics, so ???

6 hours ago, Mordred said:

The bits comply to quantum information theory

Which quantum information theory, please ?

Edited by stephaneww

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Hi Modred.

On 1/31/2020 at 2:34 PM, Mordred said:

The bits comply to quantum information theory but those bits would require quantization of gravity. Which hasnt happened yet. We have not successfully quantized gravity. In essence the theory above would require gravity to operate in discrete units (ie gravitons).

Quote

If you think that gravity is really emergent, then quantizing gravity does not make sense. Because, if you think of the analogy to thermodynamics, you also do not obtain a theory for the structure of atom by quantizing the equations for gases. Therefore, in emergent gravity one does not quantize gravity. One instead removes the inconsistency between gravity and quantum mechanics by saying that quantizing gravity is not the right thing to do.

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20 minutes ago, stephaneww said:

As someone with only a vague understanding of the relevant theories, that seems like a nice insight.

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That link describes the situation accurately with each methodology used. Excellent link.

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Found the comments after the article much more interesting.

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