Cosmological Constant Problem

Sep 2019
41
4
Azores
I was looking into Ricci Flow trying to get a better understanding of how space might evolve and stumbled across this paper, in which the author claims to have solved the Cosmological constant problem,

Ricci Flow Approach to The Cosmological Constant Problem M.J.Luo1 1Department of Physics, Faculty of Science, Jiangsu University, Zhenjiang 212013, People’s Republic of China In order to resolve the cosmological constant problem.


Is there anything wrong with his approach, or conclusion?
 
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I'm not equipped at all with the knowledge to deal with the detailed theories of cosmology, so I can't really provide any useful feedback. However, the basic signs of a shitty paper (no literature review, all self references, very old references, lack of mathematical rigour, etc.) are not there, so it seems to be okay, at least at face value. Although this paper does not seem to have been peer-reviewed, the author has previously published peer-reviewed papers in reputable journals. Perhaps someone else on the forum with more experience in theoretical cosmology can comment?
 

topsquark

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I'll add another lukewarm response. I haven't had time to fully look over the paper, and I don't think I know the subject well enough to give a definite response anyway, but I looked it over and it seems to hold together. The Math is vaguely familiar and the methods are what I would expect they might be. I think it's okay.

-Dan
 
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May 2014
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Is there anything wrong with his approach, or conclusion?
Yes. See Svend Rugh and Henrik Zinkernagel’s 2002 paper on the quantum vacuum and the cosmological constant problem. They point out that photons do not scatter on the vacuum fluctuations of QED. If they did, “astronomy based on the observation of electromagnetic light from distant astrophysical objects would be impossible”. Hence when they say the QED vacuum energy concept “might be an artifact of the formalism with no physical existence independent of material systems”, they’re right. The energy of the gravitational field doesn’t consist of quantum fluctuations. Nor does the energy of the electromagnetic field.

Rugh and Zinkernagel also refer to Wolfgang Pauli’s 1920s café calculation that zero-point energy would result in a universe that “would not even reach to the moon”,. In addition they refer to Niels Bohr in 1948 saying zero-point energy “would be far too great to conform to the basis of general relativity”. Pauli and Bohr were right because quantum fluctuations do not contribute to the energy density of the vacuum. Because they don't exist. An electron doesn't go round in circles in a uniform magnetic field because of quantum fluctuations. It does so because of Larmor precession. Because those quantum fluctuations are an artifact of the formalism. That's why there is no vacuum catastrophe., and no cosmological constant problem either.
 
Sep 2019
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4
Azores
Thanks for the responses.

Svend Rugh and Henrik Zinkernagel’s 2002 paper isnt in his list of references. He does however appear to address the issues discussed by Farsight.

Various theories on quantum gravity exist, I was once told by a clever prof that all things are just quantum fluctuations. Verlindes emergent gravity is interesting based on entanglement. So I dont completely agree with the idea that the gravitational field isnt based on some kind of quantum fluctution. Dont like the idea of Gravitons though.

Is the QSFR Quantum Space time reference frame he is defining valid in his approach?
 
May 2014
142
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Poole, UK
Various theories on quantum gravity exist
And they're all proposed by people who have never read the Einstein digital papers, and don't understand how gravity works. According to Einstein, a concentration of energy in the guise of a massive star “conditions” the surrounding space, making it neither homogeneous nor isotropic. As a result the speed of light is spatially variable. So light curves downwards like sonar waves curve downwards in the sea, see figure 10, because there’s a vertical gradient in wave speed. Then matter falls down because of the wave nature of matter. See Louis de Broglie’s 1923 letter to Nature on waves and quanta, where he said “the wave is tuned with the length of the closed path”. Then think of the electron as light going round a closed path. Then simplify it to a square path. The horizontal component bends downwards, so the electron’s position changes. In other words, it falls down:



I was once told by a clever prof that all things are just quantum fluctuations.
I think it's reasonable to say a photon is a quantum fluctuation of sorts. It has an E=hf wave nature. But it doesn't curve downwards in a gravitational field because of other quantum fluctuations. It does so because space is "neither homogeneous nor isotropic. This effect diminishes with distance in a non-linear fashion, hence curved spacetime. There are no gravitons flying around.

Verlinde's emergent gravity is interesting based on entanglement. So I don't completely agree with the idea that the gravitational field isn't based on some kind of quantum fluctuation. Don't like the idea of gravitons though.
A gravitational field is nothing to do with entanglement or quantum fluctuations. Nor is an electromagnetic field. Like I said yesterday, an electron doesn't go round in circles in a uniform magnetic field because of quantum fluctuations. It does so because of Larmor precession. It's something like a boomerang. A boomerang goes round in circles because of gyroscopic precession. A positron goes round in circles in a uniform magnetic field the other way because it's akin to a left-handed boomerang.

Is the QSFR Quantum Spacetime Reference Frame he is defining valid in his approach?
No. Spacetime is an abstract thing that models space at all time. So spacetime doesn't expand or flow. Instead it's static. It's space that expands. Luo says this on page 2: "The quantum zero-point fluctuation energies of vacuum are completely unobservable and unphysical, including the Casimir effect [46], when it is relative to a QSRF system which is also zero-point fluctuating quantum mechanically". He's saying something like we can't see the vacuum fluctuations because we're fluctuating too. He's trying to use an unobservable speculation as a reason why some other unobservable speculation is unobservable. It just doesn't work for me.
 

topsquark

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On the dance floor, baby!
Dont like the idea of Gravitons though.
Why not? It's the simplest way to set up Quauntum Gravity.

In his text "Gravitation and Cosmology" Weinberg uses the GR field equations to write the equation for a gravity wave. He uses some simple QM to show that the quantum of the gravity wave would be massless and have spin 2. (I don't recall if that is his derivation or if he based it on the work or someone else.) We call that quantum a graviton. It's a pretty general and standard analysis. I can't see any reason why this argument should not hold.

-Dan
 
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May 2014
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In his text "Gravitation and Cosmology" Weinberg uses the GR field equations to write the equation for a gravity wave. He uses some simple QM to show that the quantum of the gravity wave would be massless and have spin 2. (I don't recall if that is his derivation or if he based it on the work or someone else.) We call that quantum a graviton. It's a pretty general and standard analysis. I can't see any reason why this argument should not hold.
There is a straightforward reason, Dan. A photon has energy E=hf, and any concentration of energy has a gravitational effect. People like Weinberg have always been too accustomed to separating the various fields, which is the exact opposite of what they should be doing.
 
Sep 2019
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4
Azores
Why not? It's the simplest way to set up Quauntum Gravity.

In his text "Gravitation and Cosmology" Weinberg uses the GR field equations to write the equation for a gravity wave. He uses some simple QM to show that the quantum of the gravity wave would be massless and have spin 2. (I don't recall if that is his derivation or if he based it on the work or someone else.) We call that quantum a graviton. It's a pretty general and standard analysis. I can't see any reason why this argument should not hold.

-Dan
[/QUOTE]
The Graviton has never been detected, is the simplest reason. How does it get out of black hole is another reason. If its a simple absorbtion process where do they come from, unless its quantum foam froth etc.
 
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Sep 2019
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And they're all proposed by people who have never read the Einstein digital papers, and don't understand how gravity works. According to Einstein, a concentration of energy in the guise of a massive star “conditions” the surrounding space, making it neither homogeneous nor isotropic. As a result the speed of light is spatially variable. So light curves downwards like sonar waves curve downwards in the sea, see figure 10, because there’s a vertical gradient in wave speed. Then matter falls down because of the wave nature of matter. See Louis de Broglie’s 1923 letter to Nature on waves and quanta, where he said “the wave is tuned with the length of the closed path”. Then think of the electron as light going round a closed path. Then simplify it to a square path. The horizontal component bends downwards, so the electron’s position changes. In other words, it falls down:



I think it's reasonable to say a photon is a quantum fluctuation of sorts. It has an E=hf wave nature. But it doesn't curve downwards in a gravitational field because of other quantum fluctuations. It does so because space is "neither homogeneous nor isotropic. This effect diminishes with distance in a non-linear fashion, hence curved spacetime. There are no gravitons flying around.

A gravitational field is nothing to do with entanglement or quantum fluctuations. Nor is an electromagnetic field. Like I said yesterday, an electron doesn't go round in circles in a uniform magnetic field because of quantum fluctuations. It does so because of Larmor precession. It's something like a boomerang. A boomerang goes round in circles because of gyroscopic precession. A positron goes round in circles in a uniform magnetic field the other way because it's akin to a left-handed boomerang.

No. Spacetime is an abstract thing that models space at all time. So spacetime doesn't expand or flow. Instead it's static. It's space that expands. Luo says this on page 2: "The quantum zero-point fluctuation energies of vacuum are completely unobservable and unphysical, including the Casimir effect [46], when it is relative to a QSRF system which is also zero-point fluctuating quantum mechanically". He's saying something like we can't see the vacuum fluctuations because we're fluctuating too. He's trying to use an unobservable speculation as a reason why some other unobservable speculation is unobservable. It just doesn't work for me.
I suspect the likes of Sabine Hossenfelder and Eric Verlinde, understand how gravity works better than just about anyone on the planet. Both of them can derive Einsteins field equations using their methods. Verlinde requires no dark matter to explain why galaxies dont fly apart, I understand also Hossenfelder does not require as much dark matter to explain the galactic rotations as Einsteins field equations do. According to Verlinde both space and time are emergent.

Also an additional interesting point is that many papers have been published in support of Verlindes theories and in addition to this Ricci flow is being used by other theoretical physicists to support Verlindes theory. Of course Verlindes theory is still under development.

Edit PS Dark matter like the graviton has not been detected