I’ll just be doing a short post this week, I’ve been busy at a workshop on Flux Tubes here at Perimeter.
If you’ve ever heard someone tell the history of string theory, you’ve probably heard that it was first proposed not as a quantum theory of gravity, but as a way to describe the strong nuclear force. Colliders of the time had discovered particles, called mesons, that seemed to have a key role in the strong nuclear force that held protons and neutrons together. These mesons had an unusual property: the faster they spun, the higher their mass, following a very simple and regular pattern known as a Regge trajectory. Researchers found that they could predict this kind of behavior if, rather than particles, these mesons were short lengths of “string”, and with this discovery they invented string theory.
As it turned out, these early researchers were wrong. Mesons are not lengths of string, rather, they are pairs of quarks. The discovery of quarks explained how the strong force acted on protons and neutrons, each made of three quarks, and it also explained why mesons acted a bit like strings: in each meson, the two quarks are linked by a flux tube, a roughly cylindrical area filled with the gluons that carry the strong nuclear force. So rather than strings, mesons turned out to be more like bolas.
Leonin sold separately.
If you’ve heard this story before, you probably think it’s ancient history. We know about quarks and gluons now, and string theory has moved on to bigger and better things. You might be surprised to hear that at this week’s workshop, several presenters have been talking about modeling flux tubes between quarks in terms of string theory!
The thing is, science never forgets a good idea. String theory was superseded by quarks in describing the strong force, but it was only proposed in the first place because it matched the data fairly well. Now, with string theory-inspired techniques, people are calculating the first corrections to the string-like behavior of these flux tubes, comparing them with simulations of quarks and gluons, and finding surprisingly good agreement!
Science isn’t a linear story, where the past falls away to the shiny new theories of the future. It’s a marketplace. Some ideas are traded more widely, some less…but if a product works, even only sometimes, chances are someone out there will have a reason to buy it.
4 gravitons 
One of my all-time favorite Gary Larson cartoons features his cavemen standing near a felled Mammoth that has an arrow sticking out of its belly. The caption reads, “Remember that spot!”
Science in a nutshell, right there. Remember that spot.
BTW: Are they pronounced “mee-sons” or “may-sons”? I’d always thought the latter, but recently heard someone use the former.
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I’ve only heard people use the latter, FWIW.
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Huh. I’ve always said “mee-sons”. But I’m a mathematician, so…
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Good article. There are two good points.
One: “String theory was superseded by quarks in describing the strong force, but it was only proposed in the first place because it matched the data fairly well.”
Many wrong ideas can often match all kinds of data. Some ideas match ‘all’ data when we poke (that is, probe) them but does not work at other place. The GR (General Relativity) is such a case, totally correct when we poke it but obviously not compatible with the quantum law. The SM (Standard Model) is thus far totally correct with the largest collider (LHC) but obviously not correct as not being able to encompass the other known facts (dark energy, dark matter, etc.). Matching the data is by no means of guaranteeing the validity of the idea.
Peter Woit recently reported “Paul Steinhardt’s remorse” about his invention of inflation and his colleagues’ reaction on the BICEP2 fiasco.
Your point together with Steinhardt’s remorse points out a key issue: what is science? I wrote an article (https://tienzengong.wordpress.com/2015/05/15/paul-steinhardts-remorse-popperianism-and-beauty-contest/ ), and it might give on point of view on this demarcation issue.
Two: “Some ideas are traded more widely, some less…but if a product works, even only sometimes, chances are someone out there will have a reason to buy it.”
I have some different views on this, but not now.
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“Some ideas are traded more widely, some less…but if a product works, even only sometimes, chances are someone out there will have a reason to buy it.”
This is truly a big issue. Yet, I must disagree with you. That how this society (such as the mainstream physics community) buys things is not based on it being working neither being true or not. Let me give two solid examples.
Example one:
The Alpha (fine structure constant) is just a pure number = (1/137.0359 …). At the Wikipedia, in the “Numerological explanations” section (http://en.wikipedia.org/wiki/Fine-structure_constant ), it states (on May 17, 2015) “Attempts to find a mathematical basis for this dimensionless constant have continued up to the present time. However, no numerological explanation has ever been accepted by the community.”
Here, it is talking about the numerological formula, not physics equation. Yet, the following equation was published online over 20 years ago, long before the inception of Wikipedia.
Beta = 1/Alpha = 64 ( 1 + first order sharing + sum of the higher order sharing)
= 64 (1 + 1/Cos A(2) + .00065737 + …)
= 137.0359 …
A(2) is the sharing angle, A(2) = 28.743 degree
The sum of the higher order sharing = 2(1/48)[(1/64) + (1/2)(1/64)^2 + …+(1/n)(1/64)^n +…]
= .00065737 + …
Is there any debate about this numerological formula (which can be verified by any 8th grader)?
And this formula was and still is widely available online at many prominent physics blogs, such as,
http://profmattstrassler.com/2012/02/23/synopsis-of-the-opera-situation/#comment-6531 ,
http://physicsfocus.org/athene-donald-we-should-all-be-aware-of-our-unconscious-biases/#comment-3407 ,
http://blog.vixra.org/2013/05/16/why-i-still-like-string-theory/#comment-32568 ,
http://www.quantumdiaries.org/2015/01/09/string-theory/#comment-1788717126
Example two:
The String (M-) theory is totally useless thus far in physics {on dark energy, dark matter, calculating nature constants, string-unification, etc.}. All its great achievements {SUSY, multiverse, etc.} are wild speculations. Yet, there are zillions (hundred-thousand physicists and millions laypersons, media, etc.) buyers.
{Open string = bosonic, closed string = graviton} is fundamentally wrong.
Only G-string language can provide the string-unification. There is no other way. And,
Quark = G-string (open string)
Proton/neutron = closed string.
The Nature is in fact very simple, a process {from (1) to (2) to (3)}
(3) = calculating nature constants.
(2) = giving rise to quantum spin {(1/2) ħ}. See, https://tienzengong.wordpress.com/2014/02/16/visualizing-the-quantum-spin/ .
(1) = a process gives rise to three numbers {pi, 64, 48}, to UP (delta P x delta S > =ħ), to string-unification, etc.. This was described in detail in the book “Super Unified Theory (http://inspirehep.net/search?p=find+a+gong,+jeh+tween )”; I thus will not repeat it here.
The String (M-) theory has no clue of any kind about this process {from (1) to (2) to (3)}. We can dance with this String (M-) theory for another billion years and will not reach the (3).
That is, science (especially physics) is a process {from (a) to (b) to (c)}.
(a) = Nature holds its secret
(b) = that secret is discovered (by someone)
(c) = that secret is accepted (by all)
From (a) to (b) = enlightenment
From (b) to (c) = science (dominated by dishonesty, cowardice and ignorance).
Dishonesty = the powerful (who controls the funding, etc.)
Cowardice = the meek (who begs the funding, etc.)
Ignorance = the society.
Nature holds the secret for 14 billion years. So, if it takes hundreds years for {from (b) to (c)}, it is still a great achievement for mankind.
In conclusion, your “Working” hypothesis is wrong. {Dishonesty, cowardice and ignorance} is the dominant power in science.
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““Attempts to find a mathematical basis for this dimensionless constant have continued up to the present time. However, no numerological explanation has ever been accepted by the community.”
Here, it is talking about the numerological formula, not physics equation. Yet, the following equation was published online over 20 years ago, long before the inception of Wikipedia.”
As a non-native English speaker (I’m assuming), you’re going to occasionally miss nuances in written English. When Wikipedia says no numerological explanation has ever been accepted, “explanation” is the key word here. The community is well aware that there are many numerological formulas, but none are widely considered to actually explain anything, by dint of their numerological nature.
“The String (M-) theory is totally useless thus far in physics {on dark energy, dark matter, calculating nature constants, string-unification, etc.}. All its great achievements {SUSY, multiverse, etc.} are wild speculations. Yet, there are zillions (hundred-thousand physicists and millions laypersons, media, etc.) buyers.”
See, you’re intentionally forgetting the point I made in my post. You’re assuming that science is linear, that the purpose of string/M theory is to unify the forces of nature/explain dark matter/dark energy, because that’s “what’s next”. There is no “what’s next”. Physics is a bunch of different people working on a bunch of different things. There are people working on dark energy/dark matter/unification, and they’re called phenomenologists. There are people working on other things, and they’re called literally everyone else. Different people use different products in different ways, there is no one overarching story.
“{Open string = bosonic, closed string = graviton} is fundamentally wrong.”
That’s literally wrong, in that open superstrings have fermionic excitations. If you didn’t know that, you should probably consider that you don’t actually know enough about string theory to give a sensible critique of it. For example,
“Only G-string language…”
As I’ve explained before, the G-string is a parody made up by Warren Siegel. I can explain what a parody is, if you’re unfamiliar with the term.
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Fascinating. Will the flux tube talks be put online in the perimeter video library?
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I’m not sure, but I suspect not. It was a fairly informal workshop as these things go, and nobody was wearing a mike, so I suspect it wasn’t recorded.
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Alas, the interesting problems in QCD are not those posed by mesons that are adequately described by two quarks bound together by a flux tube of gluons. While string theory motivated refinement may work just fine to reduce computational load when calculating properties of vector mesons and pseudoscalar mesons, this is already pretty much a solved problem. Baryons are only a little harder and avoid the potential for meson state mixing inherent in the fact that mesons are bosons (and FWIW, I usually say “mee-sons”). This description breaks down catastrophically, however, for true scalar mesons and axial vector mesons, which, roughly speaking, make up a third to a half of all possible mesons (in their ground states), particularly in the scalar and axial vector mesons those which have no charm or bottom quark component.
When we look at the scalar and axial vector resonances, we often can’t even hazard more than a strong guess about whether there is a di-meson molecule, a tetraquark, a glueball, or just blend of multiple plain old (often quarkonium) two quark mesons involved. We’ve calculated very precisely the properties of the vast majority of possible glueballs since the early 1980s and not yet made any convincing sightings of one.
Also, mesons are one of the most crazy and amazing phenomena in the universe, a wonder factor that is much undersold because they are so familiar to people in the trade. Mesons have, at least, two component quarks which are fermions that have the property that no two quarks can be in the same place at the same time. Yet, once they are bound together by gluons in a meson, they can be in the same place at the same time as any other boson (e.g. photons, W and Z bosons, and other mesons). This utterly defies common sense, even though it is basic Standard Model physics.
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Yeah, I should clarify that at this point the successes are about explaining and predicting the behavior of lattice calculations of flux tubes, and don’t contribute directly to meson phenomenology. That said, there was some discussion of applying these techniques to Regge phenomenology, but that’s still in very early stages.
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