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  Could dark matter be a smoothly distributed superfluid that ripples when galaxy clusters collide and waves in a double-slit experiment, relating general relativity and quantum mechanics?

+ 0 like - 1 dislike

This Dark Matter Theory Could Solve a Celestial Conundrum

our galaxy is swimming in a superfluid sea

Dark Matter More Ubiquitous Than We Ever Thought

dark matter is smooth, distributed more evenly throughout space than we thought

Could particles of ordinary matter move through and displace a smoothly distributed superfluid dark matter causing it to wave in a double-slit experiment? Could 'particles' as large as galaxy clusters cause the superfluid dark matter to ripple when they collide?

Closed as per community consensus as the post is not graduate-level
asked Jan 4, 2018 in Closed Questions by mpc755 (-110 points) [ no revision ]
recategorized Jan 5, 2018 by Dilaton

Even though Urs's remarks in his answer are interesting and useful, the question as such looks rather like a popular level investigation than a technical graduate-level question. Voting to close to see what others think ...

Understanding what relates general relativity and quantum mechanics is not a graduate-level question?

@mpc755: In this general form not; anyone can ask vague, sweeping questions. To make them graduate level means to provide context that shows that the person asking is familiar with some of the graduate level work in the area and that narrows down the question to something that can be answered without writing a research monograph.

@Arnold_Neumaier: Do you have any idea how easy it is to correctly relate general relativity and quantum mechanics? Do you realize the whole notion of having to ask "graduate level" questions in all physics forums is keeping graduates from correctly understanding what occurs physically in nature at a fundamental level?

The Milky Way's dark matter halo appears to be lopsided

the dark matter halo of the Milky Way is dominantly lopsided in nature.

The Milky Way's halo is lopsided due to the ordinary matter in the Milky Way moving through and displacing the dark matter, analogous to a submarine moving through and displacing the water.

Offset between dark matter and ordinary matter

the gravitational potential in clusters is mainly due to a non-baryonic fluid

The center of the light lensing through the space neighboring the galaxy clusters and the center of the galaxy clusters themselves is offset due to the galaxy clusters moving through and displacing the dark matter, analogous to submarines moving through and displacing the water.

All of the evidence is evidence 'empty' space is filled with 'stuff' that is displaced by ordinary matter. It doesn't requre a research monograph to understand. All it requires is intuition and common sense.

Robert B. Laughlin, Nobel Laureate in Physics, endowed chair in physics, Stanford University, had this to say:

the empty vacuum of space … is filled with 'stuff'

Laughlin’s ‘stuff’ is the smoothly distributed, strongly interacting dark matter that fills ‘empty’ space and is displaced by ordinary matter.

Einstein: Ether and Relativity

According to the general theory of relativity space without ether is unthinkable; for in such space there would be no propagation of light

Einstein’s ether is the dark matter that fills ‘empty’ space and is displaced by ordinary matter.

the state of the [ether] is at every place determined by connections with the matter and the state of the ether in neighbouring places

The state of the dark matter at every place determined by its connections with the ordinary matter and the state of the dark matter in neighboring places is the state of displacement of the dark matter.

Wouldn't it be worth considering the possibility that what is referred to geometrically as curved spacetime physically exists in nature as the state of displacement of the dark matter?

No, playing like this with words is fruitless speculation.

Or, you could understand there is evidence of dark matter every time a double slit experiment is performed, as it is the medium that waves. Or, you can spend another 30 years and another billion dollars looking for the non-existent WIMP.

What's the point of being a graduate level physicist if you are incapable of understanding something as simple, and correct, as it is the dark matter that waves in a double-slit experiment?

1 Answer

+ 1 like - 0 dislike

This kind of idea goes back to Baldeschi-Gelmini-Ruffini 83 and due to reinventions it goes by many other names besides "superfluid dark matter" (Berezhiani-Khoury 15), such as "Bose-Einstein-condendate dark matter" (Sin 92) or "fuzzy dark matter" (Wu-Barkana-Gruzinov 00) and several others. The latter term is the one picked up in Edward Witten et. al. 17. A recent review of the literature is in Lee 17.

It's a charming idea:

A model for dark matter made up of massive but extremely light particles, whose de Broglie wavelength is at the scale of galaxies.

The idea is that on scales above that of galaxies, the predictions of fuzzy dark matter agree with the standard cold dark matter models that work exceptionally well on cosmological scales, while on scales of the size of galaxies the quantum properties of these light particles become relevant and change their effect just so as to fix the problems that standard cold dark matter models have on these scales.

A natural candidate for such ultra-light particles are axions. (This is where Witten 17 gets in, since axions are a generic prediction of string theory.)

answered Jan 4, 2018 by Urs Schreiber (6,095 points) [ no revision ]

@Urs_Schreiber why would the de Broglie wavelength need to be at the scale of galaxies?

Could dark matter be a sea of massive dark photons which are displaced by the ordinary matter?

Glenn Randall talks about dark matter

dark matter might interact with itself via some yet unknown dark force … the particles could be something we call dark photons … the dark photon would have mass

The massive dark photons displaced by the Earth pushing back and exerting pressure toward the Earth would be gravity. What is referred to geometrically as curved spacetime would physically exists in nature as the state of displacement of the massive dark photons. The state of displacement of the massive dark photons would then be gravity.

The state of displacement of the sea of massive dark photons would then be the quantization of gravity.

It's one of the big observational puzzles of our times that the assumption of WIMP cold dark matter

  1.  gives excellent agreement with observation on cosmological scales;
  2. has mighty difficulties to match oberservation on galactic scales and below, close to being ruled out on these smaller scales.

The idea of the BEC/superfluid/fuzzy dak matter model is to have the dark matter particle be massive but so extremely light, that just about on the scale of galaxies its quantum effects become non-negligible and serve to fix the second point above, while on larger scales it still behaves like classical WIMP cold dark matter and hence still reproduces point 1 above.

Hence at the moment the assumption that the de Broglie wavelelength of the BEC/superfluid/fuzzy dark matter particle is of the scale of galaxy radii is driven purely by the desire to match observation. If this holds water of course one will want to see if this may be derived from theory, but this seems out of reach at the moment.

Beware that the whole point of these models is to fit observation in the framework of established physical theory, none of this is about wild speculation about the nature of gravity that you mention. On the contrary: The failure of cold dark matter models to work on scales of galaxies and below has given rise to speculation that possibly the very laws of nature need to be modified on these scales ("MOND"), which is problematic,  to say the least. The dark matter postulate is to save established physical theory in view of astronomical observation. But the WIMP model for dark matter, which used to be most popular for years, while working great on cosmological scales, is facing severe problems on smaller scales and is on the verge of being ruled out. The BEC/superfluid/fuzzy dark matter model might be the way to fix it all.

@Urs_Schreiber, What if the notion of WIMPs is incorrect. What if dark matter fills 'empty' space, strongly interacts with ordinary matter and is the medium that waves in a double-slit experiment? Then on the scale of galaxies and smaller, the effects are no longer required to be non-negligible.

What is mistaken for lumpy dark matter is actually the state of displacement of the dark matter. The state of displacement of the dark matter is curved spacetime.

Right, I hear you voicing these wild speculations, but I try not to react to them too much. :-) That's because wild vague speculation of this sort is not suitable for this research-level forum here! Maybe at Physics.SE they'll show more tolerance. But the topic of BEC/superfluid/fuzzy dark matter is much more fascinating than these wild vague speculations, because it's serious science that actually works.

The state of "research-level" physics, correctly understanding what occurs physically in nature referred to as "wild vague speculations". All you need to understand is that the BEC/superfluid/fuzzy dark matter is displaced by ordinary matter and you relate general relativity and quantum mechanics, as the BEC/superfluid/fuzzy dark matter is what ripples when galaxy clusters collide and is what waves in a double-slit experiment. The BEC/superfluid/fuzzy dark matter is another label for de Broglie's sub-quantum medium. Maybe "research-level" physicists should try using some intuition and common sense for a change instead of making up absurd nonsense like WIMPs, which there is zero evidence of after 30 years and over a billion dollars. Maybe it's time for "research-level" physicists to stop digging and realize 'empty' space is filled with 'stuff' that is displaced by ordinary matter.

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