Theory of Everything (Superstring theory)

[Adrian]

http://www.mkaku.org/hyper.html

 

very interesting article i wanted to share.

[Radical Edward]

aah string theory and so on. excellent. Do we have any resident experts? I know I'm not....

[Radical Edward]

shame no-one wants to talk about this

[aman]

To put it in a nutshell it seems the string theory says the presence of the string creates the image to us of mass and its vibration or musical "notes" causes the appearance of the forces of nature.

It is a wonderful conjecture. To me it seems so confused in in well thought out assumptions. It seems more valid to me than spin gravity from the weight of the arguments. Having to picture ten dimensions to make it work in a realm where we know so little

in my opinion is just good conjecture. It might spark some good ideas though and the truth is out there.

Just aman.

[NSX]

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Apache Server at mkaku.org

 

:ripped:

[greg1917]

Theoretical physics I can mostly handle. All the stuff about cosmology, black holes etc. I dont have a deep understanding nor do i fully appreciate absolutely everything thats said but I can mostly follow whats going on.

 

Then theres string theory. Never have I met a more obscure, seemingly random theory. Not only do I fail to understand it in its very basic form but when i read some more intricate versions my head begins to hurt. im guessing there are several people who are in the same position as me (at least I hope so) so if anyone can manage to explain this to me id very much appreciate it.

[EvilMind]

the reason string theory is so promising is because all you need is the 11 dimensional geometry of spacetime to describe the universe.

 

however, we are not sure if the 11 dimensional spacetime we are referring to is even within our mathematical grasp. the zero brane causes us to speculate on whether our current spacetime is just a gross approximation. a new type of geometry must be developed. in accordance with a new type of calculus.

[blike]

all you need is the 11 dimensional geometry of spacetime to describe the universe.

 

All you need? Sounds like a lot to me

[Ryoken]

It seems like this multi dimentional craze sweeping across the world of physics is just a passing craze, although it does have merit.

[CHRISCUNNINGHAM]

Yes it does. Mainly because it follows the mathematics of Probability.

 

At any given point in time, any thing is possible.

 

For instance, I can sit here and type, scratch my nose, stand up and do the chicken dance, etc, etc.

 

Now because all of these things are possible, it is very logical to say that a universe where I do scratch my nose, rather than proceed with typing, is existent. And I am just simply a part of the universe, where I do not scratch my nose, but I continue typing. Very similar to the idea of "Sliders" without all the plot twists .

 

But for most, this hypothesis is "unacceptable" because it completely eradicates the possibilty of free will, and randomness.

[Ryoken]

But is anything truely random?

 

Even if that is the case, we still have our free will, it is simply similar in the 'univeres'... thus we make the same decisions, makes sense to me.

[Michael12]

Well...I am no expert by any means...but perhaps I can shed a little light

 

First of all, one must differenciate between string theory and super-string theory. There are HUGE differences. Most current research is going on in super-string theory.

 

Key differences-

 

String theory only includes particles responsible for transmitting force (bosons).

 

Super-string theories include fermions, or those particles responsible for matter. Super-string also demands that each particle (bosons and fermions) have a super-symmetric partner, as I alluded to in another post.

 

String theory actually began as a quantum theory of gravity, which is of course needed if one would like to produce a GUT. It turns out that super-string is a GUT in and of itself, alas one that only works out in 11 dimensions. As we speak, string theorists are trying to reduce that to the four we can observe.

 

String theory can do the same thing, but only in 26 dimensions.

[arivero]

The reason string theory is so promising is because Thesis Advisors are able to understand it.

 

Dtring theory was born from a duality effect noticed in scattering cross sections of some particles in the nucleus. It was a popular horse in the 60-70s, until the sucess of gauge field theory finally killed it. The consequence of it was that a lot of young physicists were trained in a completely unuseful set of mathematical techniques.

 

In the 80s-90s the phenomenological input practically dissapeared from the scene. Wild theories were searched, and the old string theory was resuscited. The old students were now advisors, so the theory got a bigger momenta than before. But it is just a social phenomena.

[Guest Prof.]

Superstring theory only explains energy fluctuations, and mass. In my opinion, that does not explain everything in the universe. Therefore, it is not a valid Theory of Everything!

 

In fact Stephen Hawking and Roger Penrose are working on a Theory of Everything, and they disregard Superstring Theory

[JaKiri]

That's pretty much all we NEED to explain at the moment

[Loki]

After reading Hyperspace and The Elegant Universe you'd think I'd be able to contribute to this discussion, but it's so hard to retain information from two 300-page books.

 

I just know that to test String Theory we'd need to harness much more energy than we could imagine. So do you think that we'll ever be able to test theories such as this? If we can't, then is it still science?

[Martin]

The reason string theory is so promising is because Thesis Advisors are able to understand it.

 

String theory was born from a duality effect noticed in scattering cross sections of some particles in the nucleus. It was a popular horse in the 60-70s' date=' until the sucess of gauge field theory finally killed it. The consequence of it was that a lot of young physicists were trained in a completely unuseful set of mathematical techniques.

 

In the 80s-90s the phenomenological input practically dissapeared from the scene. Wild theories were searched, and the old string theory was resuscited. The old students were now advisors, so the theory got a bigger momenta than before. But it is just a social phenomena.[/quote']

 

I had never heard this insightful explanation of the popularity of stringy theorizing in grad schools.

this is an april 2003 post of arivero

and it fits well with the social picture in Rovelli's "Dialog" which appeared six months later.

 

"A Dialog on Quantum Gravity"

http://arxiv.org/abs/hep-th/0310077

[arivero]

I had never heard this insightful explanation of the popularity of stringy theorizing in grad schools.

this is an april 2003 post of arivero and it fits well with the social picture in Rovelli's "Dialog" which appeared six months later.

"A Dialog on Quantum Gravity"

http://arxiv.org/abs/hep-th/0310077

 

I was reflecting a common view in Europe, as I had heard along various groups of physicists. So it is not rare the coincidence with Carlo, allthough we have never directly met.

 

I tend to think that a secondary effect of this view was the campaign for the hadronic string, kind of going back to the origins.

[Tesseract]

But is anything truely random?

 

Even if that is the case' date=' we still have our free will, it is simply similar in the 'univeres'... thus we make the same decisions, makes sense to me.[/quote']

 

This reminds me of chaos theory:

http://www.imho.com/grae/chaos/chaos.html

[Martin]

I was reflecting a common view in Europe' date=' as I had heard along various groups of physicists. So it is not rare the coincidence with Carlo, allthough we have never directly met.

 

I tend to think that a secondary effect of this view was the campaign for the hadronic string, kind of going back to the origins.[/quote']

 

I'm curious to know what view of the future is contained in an article in Nature by Witten that came out rather recently---in the past month I believe. did you happen to see it?

 

this momentum effect you describe in theoretical physics resembles a stampeed of the herds of wild buffalo, once so plentiful on the American plains.

[Martin]

here was Woit's blog about the Nature article:

http://www.math.columbia.edu/~woit/blog/archives/000032.html

 

it should have some clue as to whether Witten is imagining a

post-string-bubble future and what it looks like to him

 

what you describe----each generation of graduate students, in order to find a cooperative Thesis Advisor, must choose a field of research that the previous generation understannds----does not augur well

 

 

now there is a big glut of people trained in a possibly irrelevant branch of theory

how will the stampeed ever stop?

[arivero]

here was Woit's blog about the Nature article:

http://www.math.columbia.edu/~woit/blog/archives/000032.html

what you describe----each generation of graduate students' date=' in order to find a cooperative Thesis Advisor, must choose a field of research that the previous generation understands----does not augur well

[/quote']

Well it does not work exactly so badly. There are other mechanisms. For instance there are also a lot of Advisors that like to choose a thesis area they do not understand, so they are able to learn jointly with the student. Of course they are likely to produce a first work of lower quality, but they will produce students trained in a new area, and in this way the new area has been introduced. And remember the Advisor/Student partnership is not the only pivot of research, and there are collective learnings and self learnings during all the career path.

 

now there is a big glut of people trained in a possibly irrelevant branch of theory how will the stampeed ever stop?

Well the important thing is that they are trained to sit down for hours theorising, a very needed habit.

 

Now, there is a deeper issue in the training of physicists, and it is that the scoring system during undergraduate and graduate studies is oriented towards discussing and solving problems, with a very small focus on focusing, locating or priorising problems.

 

The final result of the training system is a herd of people that enjoys to discuss and to solve problems. Any kind. I mean, any. They do not worry if they are very far away real physical interest nor meaning; they are happy equally if they can solve them and if there are a lot of people to discuss and show the solutions they get.

[Martin]

Woit's view of the future (19 March Not Even Wrong)

 

"...Quite possibly the LHC will revolutionize physics by showing us what is really causing the spontaneous breaking of the electroweak gauge symmetry. If this happens, everyone will abandon string theory and start working on this, 1984-2008 then becoming a period in the history of physics that particle theorists try and not think about...."

 

http://www.math.columbia.edu/~woit/blog/archives/000002.html

 

it is possible, as one of your posts suggests, that the intellectual over-investment in string is more a problem in US universities than in Europe, so coming from Zaragoza you may have a different assessment

 

the funny thing was that Thomas Larsson commented that it looked as if Witten was coming around to Woit's view as expressed here (which prompted an immediate disclaimer: Woit saying it wasnt especially his point of view but just a commonplace)

[arivero]

I'm curious to know what view of the future is contained in an article in Nature by Witten that came out rather recently---in the past month I believe. did you happen to see it?

 

It did seem, to me, an article from Witten the journalist, not Witten the scientist. Just a status report. He mentions the last trendy thing in astrophysics, the dark energy, and he stress a lot the possibilities of SUSY.

 

Personally, as I indicated in other thread, I am being progressively forced to consider the reality of the 68 GeV charged scalar, which rules out the minimal supersymmetric standard model. I have not idea if SUSY will survive the test.

 

I would like to speculate that the mass of the top quark signals a remain of surprisingly low energy SUSY, being the top of the same mass scale that the fundamental bosons. It even could exist a boson degenerated in mass with the top; we have not reached this energy range yet.

 

this momentum effect you describe in theoretical physics resembles a stampeed of the herds of wild buffalo, once so plentiful on the American plains.

By now it seems it is slowing down. But the run has wiped about a lot of other approaches, that have been forced to run along with them or to sunk under their heels. Some months ago I described this process as "the flood". I have a remembrance of a seminar room with some physicists from other field having a small meeting, and taking awareness of the fact that string theory was showing an interest not on his work, but on his field. It felt as being in a hunting log down in the valley and hearing the breaking noises of the barrage up the river.

[Martin]

 

 

By now it seems it is slowing down. But the run has wiped about a lot of other approaches' date=' that have been forced to run along with them or to sunk under their heels. Some months ago I described this process as "the flood"...

 

So Urs Schreiber picked up on your antedeluvian metaphor

I tracked back to the original post:

http://golem.ph.utexas.edu/string/archives/000298.html#c000613