Physicists Prove Surprising Rule of Threes

http://www.simonsfoundation.org/quanta/20140527-physicists-prove-surprising-rule-of-threes/

by digital55 • 12 years ago

129 44 12 years ago

datenwolf• 12 years ago

I wonder if this principle can also be applied to nucleons. Protons and neutrons are each made up of 3 quarks. And there are some troubles in pinning down the radius of the proton. If Efimov scales apply to nucleons, this would imply that there are multiple scales in which quarks can arrange depending on the outside potential. This could explain the differences of measured proton radius depending on the used experimental setup. But I'm just wildly speculating here.

Panoramix• 12 years ago

This trick only works for bosons *Edit: I think.

At any rate, these depths of physics are quite complex and not very intuitive, and this kind of discovery shows it is very easy to overlook things. A giant discovery could be looming in the horizon...

anigbrowl• 12 years ago

In the lab. The paper contemplates the possibilities for nucleons too - it's just harder for spin particles: http://www.uibk.ac.at/exphys/ultracold/projects/levt/efimov/...

evanb2• 12 years ago

Sort of. There are some tricks you can play with fermions (eg. align all of their spins) to get very analogous effects.

evanb2• 12 years ago

It applies (in very rough approximation) to groups of nucleons, which is where it was first discovered. People observed that the nucleon/nucleon scattering length was surprisingly long for what they considered natural nuclear scales (or equivalently, that the deuteron was very weakly bound). The circumstance where the Efimov effect is mathematically exact is when the scattering length is infinite. Fermions in this circumstance are described as unitary.

Sadly, the Efimov effect has nothing to do with the proton size puzzle.

Source: IAANuclearPhysicist.

pavel_lishin• 12 years ago

Interesting that they referenced 22.7 falling out as similar to pi, since 22/7 is one of the simpler approximations of pi.

zorbo• 12 years ago

Completely coincidental, I'm sure.

manicdee• 12 years ago

Then you represent the number in base 23 to a few billion decimal places and find the signatures of the creators of this version of the universe.

wlievens2• 12 years ago

Obivously, since base 10 is arbitrary.

pessimizer• 12 years ago

I swear I'm not trolling, just ignorant, but could a workable theory of local hidden variables be based on this?

danbruc• 12 years ago

I am pretty sure this is not related to local realism. I would naively imagine the situation as follows (not having read anything related in detail and not being a physicist). The forces between particles become very weak with growing separation but never become zero. Now imagine throwing two ping-pong balls into a pool making ripples on the surface similar to the force field or the probability of presence of the particles. There will be a interference pattern and you can probably find a valley where you can place a third ping-pong ball and it will sit there more or less stable. Now finally imagine every pair of ping-pong balls forming the valley for the third ping-pong ball. This may of course be incredible far off from what really happens - just making up images.

araes• 12 years ago

I like the ping pong balls over the surface of a pool, that's a neat analogy. However, I am also not a physicist, but my impression is that this is something closer to how a http://en.wikipedia.org/wiki/Lagrangian_point (in particular, the L4 or L5 lagrange point) works. In fact, I think the size difference thing they describe in the article is probably very similar to how gravity, and relative object positions work out based on their mass ratios. Kind of an equilateral force balance, with a self stable state that things will naturally gravitate towards if the background energy level is low enough. Course, then that makes me wonder if there's a 4-body version with a stable tetrahedron formation?

tiglionabbit• 12 years ago

This should create many such points. At least two.

jakebian• 12 years ago

Why would this offer any threat to the no-local-HVM proofs by Bell?

lmm• 12 years ago

...no? Why and how would you think it could? I'm worried we're into "not even wrong" territory here.

ipsin2• 12 years ago

The Efimov constant is only approximately ≅ 22.7. It would be a little surprising to have a physical constant end in exactly 0.7, since it would imply that there's something special about base 10 and bases that are a multiple of 10.

Section 3 of this paper talks about the actual transcendental equation that provides the constant.

http://rsta.royalsocietypublishing.org/content/369/1946/2679...

infogulch• 12 years ago

Thank you! I was thinking the same thing about the constant being exactly representable in base 10.

3rd33• 12 years ago

Rational numbers tend to have easily recognizable patterns in their fractional digits in all bases (at least as long the numbers aren't too big), so it wouldn't imply there is something special about base 10. In fact, you can always choose the base as q for a rational number p/q and get rather simple fractional digits.

ipsin2• 12 years ago

It's not repeating digits I'm talking about, though, it's termination. If it were exactly 22.7, that's 227/10. The question would be "Why is the denominator 10?"

snorkel• 12 years ago

I vaguely recall that if a circular disc with a circumference of pi (3.14 ...) is held at an angle of 22.7 degrees relative to a flat surface, it projects an ellipse that has a circumference of 3.000 Coincidence? Eh, probably. Might've also been 26.8 degrees.

ColinDabritz• 12 years ago

One common association of those digits with PI is the handy approximation of 22/7 accurate to three digits, off by just over .0004.

I stress that this is an approximation only! I had to explain about PI being irrational rather than exactly equal to the shortcut approximation to a couple co-workers, explaining some poor behaviors in their rotation function.

igonvalue• 12 years ago

It looks like it's only accurate to two decimal places; the circumference is approximately 3.02.

http://www.wolframalpha.com/input/?i=ellipse+1%2F2%2C+cos%28...

thomasahle• 12 years ago

“Although we didn’t see an infinite number of them, there’s pretty strong evidence when you see three in a row,” - What a physicist thing to say :P

sp332• 12 years ago

One time, Feynman was giving a lecture to some middle-school kids. He used the date of some battle as an example, but he got it a bit wrong and the kids immediately corrected him. He laughed and said "Hey! 3 significant digits is pretty good for a theoretical physicist!"

ctdonath• 12 years ago

3, 5, and 7 are prime, therefore 9 is prime.

graycat3• 12 years ago

No: 11 is prime. 13 Is prime. So 9 is just an exception!

ph0rque• 12 years ago

Quite fitting...

“What you see is three groups, in three different countries, reporting these multiple Efimov states all within about one month,” said Chin, who led one of the groups. “It’s totally amazing.”

gpvos• 12 years ago

How far were these groups spaced apart?

Evgeny• 12 years ago

More than 40 years after a Soviet nuclear physicist proposed an outlandish theory that trios of particles can arrange themselves in an infinite nesting-doll configuration, experimentalists have reported strong evidence that this bizarre state of matter is real.

I think it's quite awesome that Vitaly Efimov lived to see his theory being proved (or, at least, to see strong evidence in its favor).

It always makes me sad when I read about scientists who made great discoveries just to be laughed at until their days end, and then their theories are proved after they are dead.

A classic example is Alfred Wegener, who postulated continental drift just to be ridiculed., but of course there are many, many others.

http://en.wikipedia.org/wiki/Alfred_Wegener

Another, even more tragic story is that of Ignaz Semmelweis, who not only pioneered antiseptic procedures in hospitals, but, to my mind, proved their effectiveness beyond any reasonable doubt, was rejected, and died tragically.

http://en.wikipedia.org/wiki/Ignaz_Semmelweis

Physicists Prove Surprising Rule of Threes

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