I've suggested (& published in 18 journal papers) a new theory called quantised inertia (or MiHsC) that assumes that inertia is caused by relativistic horizons damping quantum fields. It predicts galaxy rotation, cosmic acceleration & the emdrive without any dark stuff or adjustment.
My Plymouth University webpage is here, I've written a book called Physics from the Edge and I'm on twitter as @memcculloch

Saturday, 12 November 2016

Critique of Verlinde's Gravity

People have been sending me Verlinde's new emergent gravity paper wanting me to comment on it. I started reading it and I'm afraid I stopped at the sentence 'code subspace in microscopic bulk Hilbert space'. I skimmed the rest. He focuses on gravity, and just assumes inertia, and is proposing a new force that starts to appear at large scales. Although there are similarities to MiHsC in that he uses the Unruh temperature formula and information, there are many observations that falsify Emergent Gravity:

1) Emergent gravity predicts an anomalous effect that occurs only on large scales, and so it is falsified by the many tiny globular clusters and small satellite galaxies that show even more of an anomalous rotation effect than big galaxies (MiHsC is successful with these minnows too because it predicts anomalies at low accelerations, instead of just large scales, see paper). Emergent Gravity also cannot deal with many other anomalies like the cosmic acceleration, the flybys and the emdrive. MiHsC explains all of these.

2) Entropic gravity has been falsified by a detailed comparison with galaxy rotation curves: https://arxiv.org/abs/1609.05917 (Lelli et al., 2017, to be published in MNRAS letters).

3) Emergent Gravity has been falsified by experiments in which uncharged neutrons were confined in the vertical direction by making them bounce off a mirror below, and allowing gravity to pull them down. It was found that, in agreement with quantum mechanics, the neutrons did not move continuously along the vertical direction, but jumped from height to height like mountain goats. Entropic gravity predicts the wrong heights (see the Kobakhidze reference).

4) Emergent Gravity relies on something called code subspace, which is something we cannot directly see, so it is another kind of informational dark matter that is difficult to test for directly.

It is strange people that people are considering Emergent Gravity and are not discussing MiHsC / quantised inertia which is far simpler, requires less new physics, is based only on observable things, and predicts far more. To summarise:

1. MiHsC/quantised inertia is deliberately based only on things we can see (empiricism): visible matter, the speed of light, the cosmic diameter, and Unruh radiation that was already predicted and is at least observable, and may have been seen already (Unruh confirmed?).

2. MiHsC is simple. Emergent gravity is complex and Byzantine, and needs more untestable assumptions (like code subspace) than you can shake Occam's razor at, MiHsC needs only one new assumption and 6 lines of maths to predict galaxy rotation and many more anomalies on a huge range of scales.

3. The new assumption in MiHsC: that quantum mechanics (the zero point field) and relativity (horizons) interact on all scales via the uncertainty principle simply gets rid of the dark sector and unifies physics.

4. The same mathematics that leads to MiHsC, also predicts gravity, so MiHsC predict both gravity and inertia.

5. MiHsC predicts the many anomalies that have been seen in recent years (29 or so of them), but also makes very specific predictions for new things that can be looked for (eg: early galaxies span faster at the same visible mass, the emdrive can reverse if you change its aspect ratio..)

Of course, it's good that Verlinde is at least trying to solve galaxy rotation without vague dark matter, but he is still suffering from the excess-baggage problem of theoretical physics. He had to start from general relativity and try to add invisible elements to it. The result is complex, contrived and doesn't fit the data.

Quantised inertia / MiHsC fits the data, and is far simpler because you don't have to add anything unobservable. All you have to do is admit that quantum mechanics and relativity interact via horizons and the uncertainty principle (summary).

References

Kobakhidze, A., 2011. Once again gravity is not an entropic force. arXiv

McCulloch, M.E., 2012. Testing quantised inertia on galactic scales. arXiv

Verlinde, E., 2016. Emergent gravity and the dark universe. arXiv

20 comments:

qraal said...

Totally missed that refutation of Verlinde. Thanks Mike!

Andrew Jaremko said...

Mike - Brlliant! I hope you put your critique where it belongs in the discussion of the paper! IANAS (I Am Not A Scientist) so I don't (yet) know where to look to check for it.

duane oldsen said...

Oddball Query. Can MiHsC survive "transplantation" from Copenhagen Interpretation QM to Bohmian/ pilot wave QM?

Mike McCulloch said...

Duane. Well, I don't accept either of those QM interpretations. I have an informational interpretation of quantum mechanics that I think is better and that I am trying to publish (I've submitted it 4 times so far). It is testable.. I guess you are referring to the NASA EW hypothesis for the emdrive. I looked through it last year and, although I admire those EW guys for the experiments they do, I'm afraid I don't believe their hypothesis (at least, the version I saw last year) since there were too many arbitrary adjustable parameters (they had 3), too much was hidden in complex computer modelling, their 'acoustic vacuum' model appeared contrived and in my opinion would produce a different kind of nature to the one we see.

duane oldsen said...

The recent emdrive paper from NASA was the proximate reason for me mentioning the Bohmian interpretation, yes, though the Couder oil pan experiments are fascinating and convincing evidence for the pilot wave interpretation, or at least evidence for some QM variant beyond the Copenhagen interpretation. The Copenhagen interpretation has long struck me as far too metaphysical for its own good.

Looking forward to reading your own work when it busts past the gatekeepers. They can't hold it back much longer. :)

David Schroeder said...

Reading Erik Verlinde's paper, or I should say attempting to read it, makes me appreciate the extraordinary intelligence of some people; how they can take so many disparate concepts and weave them into what appears to be a coherent whole. I'm glad you provided an overview, to save me from a brain meltdown!

Zephir said...

/* MiHsC is simple. Emergent gravity is complex and Byzantine */

Why not to learn from recent past of stringy/susy models (theory is too strong word here)? The complex and opaque models provide the occupation for more theorists, the larger groups of theorists is more loud and influential in their promotion. Occupational circle gets closed.

Mike McCulloch said...

David: Complexity is not impressive in science, simplicity is.

Mike McCulloch said...

Zephir: The way you describe it, it sounds like an priesthood where you have to memorise complex texts to gain admittance and lay people then dutifully stand back in awe.. Yes, that sounds like the mainstream :) As for me, I'd like to know the real answer, and I have no desire to join such a group.

Zephir said...

The general socio-psychological principles, which kept the epicycle model and stringy/susy models in the game long after these models were disproved by observations are the same, only people involved changed. But once you'll establish larger group of sympathizers around your theory, you'll face similar problem like the epicycle theory: the formal agreement of theory with experiments still doesn't imply, that the underlying physical mechanism cannot be different.

As for latest Verlinde's model, it's based on projective holographic geometry more, than on emergent mechanism. If you remember what I criticized about your theory (i.e. the explanation of very local effects with very distant ones), then exactly the same could be applied to Verlinde theory also. In this respect your theory shares more common aspects with Verlinde model, than you may be probably willing to admit in a given moment... ;-)

Zephir said...

BTW How the MiHSC theory accounts to the fact, that some galaxies poor of dark matter, whereas some others have surprisingly high content of dark matter? The holographic model holds somewhat stronger position here, as it allows the dark matter to depend on the amount of matter in their neighborhood. Of course I'm aware that it occasionally would fail just from the same reason, but still...

Mike McCulloch said...

Zephir: MiHsC is infinitely better than the epicycles because it has zero adjustability, the epicycles had huge adjustability. Verlinde's stuff is extremely complex, has a huge number of assumptions and is never compared with any data. It is falsified because it cannot explain dwarf galaxies. In contrast MiHsC predicts the 153 galaxies in the SPARC catalogue exactly, including dwarfs, without any adjustment, and it is a simple as you can get.

Zephir said...

The epicycles had low adjustability, as they were tightly fitted to experimental data. They enabled to predict solar eclipses with high precision (few hours). MiHsC doesn't predict 153 galaxies, it predicts their rotational acceleration from observable mass.

Zephir said...

BTW MiHsC also uses diameter of observable Universe for it - how this value is determined? Being an integral quantity of the red shift, it could explain, why MiHsC gives slightly better predictions than MOND.

Mike McCulloch said...

Zephir: I now use Theta = 8.8x10^26m which is the co-moving cosmic diameter, ie: the diameter now, rather than the diameter when the light was emitted.

Zephir said...

Verlinde's emergent gravity vs MOND and the case of eight dwarf spheroidals For a point particle, or outside an extended spherically symmetric massive object, Milgrom's empirical fitting formula is recovered. However, Verlinde's theory departs from MOND when considering the inner structure of galaxies. I'd interested, how the MiHsC theory would handle it.

Mike McCulloch said...

Zephir: Good question. That's on my to-do list.

Zephir said...

Perspective on MOND emergence from Verlinde's "emergent gravity" and its recent test by weak lensing

Daniel Fodor Fernandes said...

I want to understand why physicist Erik Verlind along with physicist Sabine Hossenfelder insist on affirming that there is emerging gravitation, why ?. After all the test performed with "gravitational lenses" belong to General Relativity. Why did Erik Verlind appropriate or steal the Mond Theory?

abhishek mane said...

The gravity of star is researched by earth measured and also described in and Ezekiel