String theory is what?

[lpetrich]

I've heard E6 theories that aren't string theory are even more complicated and unlikely than strings itself.

The Dagda, don't make me laugh. Why don't you read the Wikipedia articles about E6 or E8 some time? Even a E6 GUT is less complicated than its string-theory superset: the HE superstring.

I'll take on the simple case of SO(3) / SU(2). You learn about its representations when you do quantum-mechanical angular momentum. Different angular momenta = different representations of that algebra. For angular momentum j, a system has (2j+1) states, corresponding to the AM in one direction being -j, -j+1, ..., j-1, j. Thus, AM vector can be represented as a set of 3 matrices with dimension (2j+1).

3D rotations (Mathematica notation):
I*{{{0,0,0},{0,0,1},{0,-1,0}}, {{0,0,-1},{0,0,0},{1,0,0}}, {{0,1,0},{-1,0,0},{0,0,0}}}
Spin 1, dimension 3

2D Pauli matrices (Mathematica notation):
(1/2)*{{{0,1},{1,0}}, {{0,-I},{I,0}}, {{1,0},{0,-1}}}
Spin 1/2, dimension 2

Notice that they have the same commutation: [a,b] = a.b - b.a
[L1,L2] = i*L3, [L2,L3] = i*L1, [L3,L1] = i*L2

The Pauli matrices are thus the rotation-matrix generators for the spins of spin-1/2 particles.

The case of SO(2) / U(1) is much easier, of course.

I don't doubt it makes perfect sense to those studying that sort of maths, I just wonder why anyone would want to study that sort of idea myself. Unimaginably complicated and boring IMHO. the Universe we can see is interesting, maths for its own sake is not. But then I am not a mathematician.

The Dagda, what I described is used all the time -- look at quantum-mechanical angular momentum some time.

The up and down quarks have relatively low mass, thus making their flavors have an approximate symmetry of SU(2). The strange quark is somewhat more massive, giving a less-approximate symmetry of SU(3). Quantum Chromodynamics features a degree of freedom called "color" that follows SU(3). Etc.

By the way don't let my contempt for E6 as science if not respect for its maths give you the impression I am expecting you to defend it or care to much beyond the equations themselves.

The Dagda, you have a LOT to learn.

[Nautilidae]

I see you have no sense of humour either.

Is that truly what you believe, or is that an excuse for interpreting a joke as an actual statement against string theory?

So I'm right you can't explain to me why it is or isn't testable I think we're done here then.

... How did you reach this conclusion? I have explained why extra dimensions were testable in my last post. Are you actually reading my statements?

You basically side with String Theorists and I with the mainstream lets see who's right eh? I don't think you really understand what you are defending tbh though.

What is with you and labeling anyone who supports string theory "outside of the mainstream"? I've given examples of several mainstream scientists that support string theory, including a Nobel Prize winner.

"This is false" as an argument highlights only your lack of understanding of that which you are defending.

Why is it false what experiment can and will distinguish strings and why?

This as an argument highlights only your lack of understanding of debate. I responded to points that I've already dealt with with "This is false, as I have already demonstrated." I already showed you string theory makes testable predictions, the experiments that will make those predictions, and WHY those aspects are testable. Of course, you ignore them all.

Oh shut up you're an ill educated school boy what the hell do you know.

This is an ad hominem in it's purest form as well as an intellectual dead-end.

I wouldn't of presumed to tell people with more qualifications than me what physics is the fact you do is sad.

First, just because someone is a physicist doesn't mean that their statements are in any way correct.

Second, I never explained to him what physics was. I was debunking his out-of-date arguments.

The fact that just saying this is facile about some professional scientists is enough for you to have argued the point shows that you really do have no idea even why you believe what you do, it's just what you were told by propagandists.

Again: The points with which I had already dealt were labeled as such. Please learn to READ properly.

Do you understand Euclidean geometry, imaginary numbers, general and special relativity: Non Euclidean geometry, vectors, tensors any maths that relates to physics at a level where you can begin to understand the underlying concepts, feild theory basic concepts? If not then there's little point exploring why String Theorists are so convinced of their fairies.

This just demonstrates my point. The fact that someone doesn't understand something as well as others does not make their arguments any less correct. This is a form of an ad hominem; you are attempting to discredit the person making an argument rather than the argument itself.

And there's little point in continuing this discussion. That's not an ad hominem ,that's just being at a stalemate because you don't have the education to argue further.

Yes, it WAS an ad hominem. An ad hominem as an attempt to discredit the personal traits of a person in order to discredit their arguments. That is EXACTLY what you are doing. I am certainly able to argue further, as I have already shown by showing that that man's statements were incorrect.

Now I'm not claiming to be an expert far from it but I do understand what the objections are at a higher level than the 15 years olds curriculum.

First, you know nothing of my curriculum.

Second, apparently you don't understand, as I've debunked every argument that you and your idle's have made thus far. Plus, I've corrected you on a number of statements that you've made involving physics.

Although I've already explained several times why string theory is testable, I'll explain again:

String theory makes the prediction of extra dimensions. They can be tested in particle accelerators with an energy scale in the TeV range. This is because micro black holes would form in the collisions.

The Planck mass is approximately 1.2209×1019 GeV/c2. In terms of energy, this is extremely high. The Planck mass serves as a minimum mass for black holes. However, in string theory, because of the extra dimensions, the Planck mass is reduced considerably to about 1 TeV. Proton-proton collisions at the LHC have a total energy of about 14 TeV, and the energy produced by colliding lead nuclei at the LHC is over 1000 TeV. In order for black holes to form, the collision energy must be higher than the mass of the black hole. Since the LHC beyond accomplishes this, we can expect black holes to form at the LHC. There is also the possibility that string balls, massive tangled string states, will also form with masses of about 3 TeV, also thanks to the extra dimensions.

In other words, if the extra dimensions of space-time exist, we can expect black holes to form at the LHC. In fact, there is a proposed model that shows that the Higgs boson can come from a string ball produced at the LHC.

Oh look: A prediction made by string theory that is testable with current accelerators!

[JimC]

The Dagda wrote:

...Oh shut up you're an ill educated school boy what the hell do you know...

This is not an acceptable way to address a fellow member of this forum. I and others have spoken to the participants of this thread about the way we conduct ourselves on Ratz. You now have a 24 hour vacation from the forum to consider how you relate to others while here.

[lpetrich]

String compactification can also happen by other routes, like "orbifolds". These are essentially the unit cells of space groups: displacement + rotation + reflection.

Wallpaper group - Wikipedia, the free encyclopedia lists the 17 2D space groups. Their unit cells are various 3-sided and 4-sided polygons.

That aside, here's a summary of how how many multiplets various theories have. Left-handed and right-handed / particle-antiparticle together:

Low-Energy (MS)SM: 5 + 3*4 + 4 = 21
Unbroken (MS)SM: 2 + 3*6 + 3 = 23
SU(5) GUT: 2 + 3*3 + 1 = 12
SO(10) GUT: 1 + 3*1 + 1 = 5
E6 GUT: 3*1 + 1 = 4
E8 GUT / HE String: 1

The HE string actually has E8*E8 gauge symmetry. The 6D compactification interacts with only one of the E8's, making the GUT's and the SM. The other one is unbroken, and produces a "hidden sector". According to some theorizing about it, its gauginos will condense, breaking supersymmetry. This breaking is then transmitted to the accessible particles by some route.

Hidden-sector hypotheses are difficult to test, for obvious reasons, but we may get some clues about it from features of supersymmetry breaking in the accessible particles. Features like the sfermion and gaugino mass parameters. They are expected to be unified at GUT energies, a hypothesis that may eventually be tested.

[Nautilidae]

String compactification can also happen by other routes, like "orbifolds". These are essentially the unit cells of space groups: displacement + rotation + reflection.

Like I said in my post, there are other methods of compactification, but I listed the basic method. I'm not trying to one-up you; you obviously know more about this than I do.

That aside, here's a summary of how how many multiplets various theories have. Left-handed and right-handed / particle-antiparticle together:

Low-Energy (MS)SM: 5 + 3*4 + 4 = 21
Unbroken (MS)SM: 2 + 3*6 + 3 = 23
SU(5) GUT: 2 + 3*3 + 1 = 12
SO(10) GUT: 1 + 3*1 + 1 = 5
E6 GUT: 3*1 + 1 = 4
E8 GUT / HE String: 1

The HE string actually has E8*E8 gauge symmetry. The 6D compactification interacts with only one of the E8's, making the GUT's and the SM. The other one is unbroken, and produces a "hidden sector". According to some theorizing about it, its gauginos will condense, breaking supersymmetry. This breaking is then transmitted to the accessible particles by some route.

So one E8 interacts with the compact dimensions and the other E8 does not? Is there any particular reason for why one E8 is hidden? Is it related to the seperation of the HE string excitations?

[lpetrich]

So one E8 interacts with the compact dimensions and the other E8 does not?

Yes.

Is there any particular reason for why one E8 is hidden? Is it related to the seperation of the HE string excitations?

It's "hidden" because it only interacts extremely weakly with our E8. The two E8's don't have gauge-field interactions with each other, like they do internally, making them act like separate gauge multiplets.

[Nautilidae]

So one E8 interacts with the compact dimensions and the other E8 does not?

Yes.

Is there any particular reason for why one E8 is hidden? Is it related to the seperation of the HE string excitations?

It's "hidden" because it only interacts extremely weakly with our E8. The two E8's don't have gauge-field interactions with each other, like they do internally, making them act like separate gauge multiplets.

Okay, that makes sense. Thank you.

[newolder]

Predictions of theory observed in nature. Oh yes.
http://cerncourier.com/cws/article/cern/41717

[Nautilidae]

Predictions of theory observed in nature. Oh yes.
http://cerncourier.com/cws/article/cern/41717

Someone posted this on RS.

EDIT: I now realize that that someone was you

[The Dagda]

The Dagda wrote:

...Oh shut up you're an ill educated school boy what the hell do you know...

This is not an acceptable way to address a fellow member of this forum. I and others have spoken to the participants of this thread about the way we conduct ourselves on Ratz. You now have a 24 hour vacation from the forum to consider how you relate to others while here.

Perhaps next time you aught to warn me instead of just banning me without one like a 7 year old. God moderators are useless in the main. No that's unfair not in the main almost always.

[The Dagda]

So we are back to I am right they are wrong. Sorry but you don't know what you are talking about, and thus I can't take you seriously. The actual fine measurements are too small too distinguish strings, unless you are a String Theorist then you just pretend they do distinguish it instead of still leaving it all up in the air like some delusional idiot with a chip on his shoulder.

By the way I may of been banned for 24 hours for saying what I said but that doesn't make it any less true. Which is what I meant by not an ad hom ie it is not a fallacy, it would be truth stated, claiming it to be an ad hom fallacy would in itself be a fallacy.

String theory failing to win any recognition from the Nobel prize commitee and science in general for 30 years and counting. At this rate it will become a law in 5 years if the String Voodoo witch Drs get their way.

@Ipetrich there aren't 6 dimensions (as far as we can empirically determine) that's why its unnecessarily complicated. And yes I have a lot to learn (I'm a student the clue is in the name) but then I don't whine like a girl when someone states the obvious. And I'm also less interested in pure maths than arm waving. But then I intend to become a real scientist not an apologist for my religion. I complained about nautilidae's ad hominem and what do you know claiming someone cant read properly is not an ad hom worth infraction than telling the truth about someone is, fuck yeah!

Call the consistency police. Yeah I know I'm a n00b I don't matter, and I don't have to be treated with any respect. I get it just ignore me and pretend you are perfect, usual moderation garbage.

And Oh god here comes the cavalry, another devotee for the religion. Newolder so lost in his own propaganda that wood and trees mean nothing to him.

So one E8 interacts with the compact dimensions and the other E8 does not? Is there any particular reason for why one E8 is hidden? Is it related to the seperation of the HE string excitations?

So one magical elf interacts with another magical elf and we wave our wands and say abra cadabra and on stumbling through the maths we find we are in Narnia.

String excitations? They don't exist as yet? What are you talking about?

Question: What is string theory?

David Albert: String theory is a version of quantum mechanics. That is, quantum mechanics is less a completely specific theory than a class of theories, theories that involve this principle of superposition that we were just talking about, theories whose fundamental equations of motion have a certain particular kind of mathematical structure, so on and so forth. So one can enumerate five or six basic principles of quantum mechanics, okay, and these principles allow for a rather wide range of more specific claims of exactly what elementary systems the world is made of and so on and so forth. So string theory is one version of quantum mechanics, one version of a quantum theory. It's a theory whose fundamental ontological entities aren't particles, but these one-dimensional objects, these strings. And that fundamental ontology looks promising for all sorts of reasons, especially in regard to attempts to make a coherent quantum theory of gravitation and so on and so forth.

But in the context of our discussion here, it's one version of a quantum theory. It shares all of the weird properties that we were just talking about, the measurement problem, the principle of superposition, so on and so forth, with every other quantum theory. And these foundational problems, especially the measurement problem, come up in string theory in exactly the same way as they come up in older versions of quantum mechanics.

Question: How might we establish the truth of string theory?

David Albert: We need to smack particles together -- you know, this is of course a -- one doesn't want to anticipate what's going to happen, and maybe tomorrow somebody's going to figure out some much more clever and much cheaper experimental method of distinguishing between string theories and other quantum theories that we have -- but insofar as we know at the moment, the only way of getting a handle on whether or not string theory is true is going to be the very brute-force, very expensive project of building these huge accelerators that are going to smack particles together with such intensity, that is with energies reminiscent of the energies that the particles had in the very early milliseconds of the life of the universe, where the predictions of string theory are going to differ from the predictions of other interesting quantum theories that we have on the table. So it's going to be a matter of doing those experiments.

Question: Is the Large Hadron Collider capable of doing this?

David Albert: It's -- no, even that -- I mean, there may be -- the evidence that we would get even from that, as far as I understand the matter, would still be rather indirect, although there are things that could emerge from those experiments which would be a more comfortable fit for certain string theories than for other theories that we have on the table. But even that evidence is going to be rather indirect. You know, what most people say nowadays is, look, the best evidence we have for string theory is that there is a phenomenon of gravitation, and we don't know any way besides string theory of making gravitation compatible with quantum mechanics.

What a liar String Theorists huh?

It's all lies CERN does make it a theory, magical gravitational blue shift which wont be distinguishable from red shift and has never been observed also proves it, wah, wah, wah, wah. (Charlie brown type noises)

Your only lying to yourselfs.

"String Theorists don't make predictions they just make excuses"

Richard P "my peer review doesn't matter because String Theorists say so" Feynman

Feynman did significant work while at Caltech, including research in:

* Quantum electrodynamics. The theory for which Feynman won his Nobel Prize is known for its accurate predictions.[19][20] This theory was developed in the earlier years during Feynman's work at Cornell. He helped develop a functional integral formulation of quantum mechanics, in which every possible path from one state to the next is considered, the final path being a sum over the possibilities (also referred to as sum-over-paths or sum over histories).[21]

What the fuck does that chump know eh. Oh look a Nobel prize.

[JimC]

Well, the break in angry vituperation was nice while it lasted...

There was actually some civilised discussion of the topic...

[The Dagda]

Well, the break in angry vituperation was nice while it lasted...

There was actually some civilised discussion of the topic...

Oh just ban me already. Why don't you after all I don't deserve any respect just to be treated like a child.

There wasn't anything on topic but no you didn't notice that because you were too busy being self righteous as per your job title.

E8 is not string theory its another of those plagiarised ideas that may or may not be correct. String theory owns everything it is a theory of anything.

[JimC]

Well, the break in angry vituperation was nice while it lasted...

There was actually some civilised discussion of the topic...

Oh just ban me already. Why don't you after all I don't deserve any respect just to be treated like a child.

My simple point is this. No one minds an alternative viewpoint on String Theory, but what gets tiresome is to have a thread dominated by petty emotional displays more suited to a poorly run kindergarten...

[The Dagda]

Well, the break in angry vituperation was nice while it lasted...

There was actually some civilised discussion of the topic...

Oh just ban me already. Why don't you after all I don't deserve any respect just to be treated like a child.

My simple point is this. No one minds an alternative viewpoint on String Theory, but what gets tiresome is to have a thread dominated by petty emotional displays more suited to a poorly run kindergarten...

Stop pretending you are a grown up you're an embarrassment to your professions. Pay peanuts get monkeys, pay nothing get nothing. Communism in action. You should warn someone before you ban them, it's moderation 101. In the real world that is.

Mod rule 1 (the one and only rule)

Never admit when you are wrong, never for that way lies integrity!

Yeah we know mods aren't subject to their own rules and are above the law. We get it.

"Go to your room child!"

This is very much a theme isn't it, people who don't do criticism and can't explain it in any manner when faced with it.

I'm sorry but adults argue just as much as children, war is inevitable. Perhaps you despise human nature. Thought police.