String theory

[Ferdinando]

"The Elegant Universe" made them reputable in the lay-audience world.

Have you read the papers by Alan Sokal ? and, its counterpart in the Bogdanov affair ?

 

The public may have difficulties taking theories seriously.

 

String theorists don't know whether or not nature/reality can be described by this theory. But, they believe it has a very good chance of being true.

 

The Large Hadron Collider (LHC), which is located in France and Switzerland, is scheduled to go online in 2007. It is expected to provide evidence to support aspects of string theory, such as supersymmetry, that is every known elementary particle and force carrier particle has an as-yet-undiscovered partner particle, known as a superpartner.

 

It is a big deal. Because such findings would support string theory. And, even if string theory is not correct, supersymmetry could be a feature of the universe.

 

The LHC may well discover that the principle of supersymmetry is one that is needed to describe our universe.

 

Particle physicists are highly skeptical of string theory. String theory which brings the radical notion that there are more dimensions than we have traditionally accepted with essentially no experimental support, the built-in conservatism kicked in.

 

And, there is the misconception of what is supersymmetry. It is not a thing, it is rather a relationship between what things are made of and the cause that makes those things clump together.

 

Any thoughts ?

[CPL.Luke]

on what?

 

unfortunatly string theory went for a long time without producing any do or die predictions (and it still hasn't), the theory is more a thing of mathmatical interest than scientific at this point, as you can build none string supersymmetric models and all that. So the theory doesn't really add any predictability to anything, and even more so its founding assumptions are just bad science. Why should the fundamental particles be made of vibrating strings? why not vibrating spheres? or elipses? or purple monkeys doing a happy dance?

 

 

Also its possible that the LHC could find some supporting evidence that string theory is really what the universe looks like, but that same evidence can work in other existing theories, and even if the LHC doesn't find anything to support string theory, you can just formulate a version that said that it shouldn't have found any evidence.

 

 

this is not good science.

 

This comic sums up string theory rather nicely

 

http://xkcd.com/c171.html

[Severian]

The Large Hadron Collider (LHC), which is located in France and Switzerland, is scheduled to go online in 2007. It is expected to provide evidence to support aspects of string theory, such as supersymmetry, that is every known elementary particle and force carrier particle has an as-yet-undiscovered partner particle, known as a superpartner.

 

It is a big deal. Because such findings would support string theory. And, even if string theory is not correct, supersymmetry could be a feature of the universe.

 

Sorry, but that is such bollocks.

 

1. The discovery of supersymmetry at the LHC says nothing about the plausibility of string theory.

 

2. The non-discovery of supersymmetry at the LHC says nothing about the plausibility of String Theory.

 

So not much to do with string theory then....

[ajb]

Severian is correct.

 

If supersymmetry is found then it would be consistent with string theory, but not evidence of string theory.

 

If supersymmetry is not found then one can argue that the energy scale of supersymmetry is higher then expected. This would not be inconsistent with string theory or supersymmetry in general. This means that you cannot "disprove" supersymmetry in nature!

 

So I would say if supersymmetry is found then I would take it as an indication that string theory is on the right lines.

 

Even if supersymmetry is not seen in nature, it's mathematical beauty and power means that "super-tools" will be with us forever, both in physics and mathematics. (Also the BV-BRST formulism should be considers as a supersymmetry, there is a lot of intersting geometry behind this).

 

John Ellis (CERN) is giving a talk called " Novel signatures for supersymmetry" in Manchester. I will be attending and may ask what he thinks about this.

[ajb]

To para-phrase John Ellis

 

"String theory needs supersymmetry more than supersymmetry needs string theory".

[Severian]

I am tempted to add:

 

John Ellis needs supersymmetry more than supersymmetry needs John Ellis.

[Ferdinando]

Hi Ajb,

 

Oh, cool ! you're going to a lecture. I look forward to reading your next posting.

[ajb]

I am tempted to add:

 

John Ellis needs supersymmetry more than supersymmetry needs John Ellis.

 

That is funny, but is it ture?

 

You know this area of science better than I do.

[Severian]

Well, John Ellis is the ultimate fanboy of supersymmetry. But I was being tongue in cheek - I know John very well, and have a lot of respect for him. He has a bit of a reputation of overpublishing - he publishes a huge amount of papers, most of which don't have much content, but his work still contains more constructive results on susy than pretty much anyone else.

 

There is this joke in particle theory, that every published phenomenologist is at most one collaboration removed from John, i.e. Everyone has written a paper with someone who has written a paper with John. The scary thing is, that it is true!

[ajb]

I just looked a SPIRES and there is 904 papers written by John Ellis. So I can beleive you!

 

I have seen him twice now, but yesterday was the first time I have spoken to him. I am sure our paths will cross again, even though I do not do phenomenology.

[mnmclockman]

Okay, I'm new here and a total layman. 90% of what I read here, I do not fully understand. So it takes real audacity (or stupidity) to offer this post. But, at the least, it may give you all a laugh. So here it is, my view of string theory.

The first thing that troubled me about string theory was the increasing number of dimensions that were being resorted to. Now, the idea of 3 dimensions has also always troubled me; sort of a vision of a world of perpendiculars and squares. when I set up a milling machine there are three axes to adjust. But, always frustratingly, there are infinite other directions that I can't move the milling table in. Enough preface.

The string that vibrates doesn't exist. There is only the vibration of the string, but no string. If the string vibrates randomly around a center point, it ultimately creates a sphere of vibration. So the sphere is the basic definition of dimension, its dimensions are infinite, but it has no size because it is merely a vibration. So it is not only a sphere, but also a point. The answer to the 11+ dimensions thing is that our world has One dimension. It is a point.

The strings (which don't exist) vibrate, and the vibrations can differ in many ways: frequency, amplitude, and so forth - you would know about that, I don't. The variations in the vibration properties of the strings determine if the strings appear as energy, matter or time. Entirely different strings can group, or cluster (virtually infinite numbers of them) because of some commonality. I think of the analogy of many different waves, but all with the same harmonic vibration on them, and harmonics on the harmonics, etc.- a commonality. And these clusters of commonalities are the leggos of all matter and energy in the universe.

Rather than rambling further (which I certainly could do), I will stop now and brace myself for the gale of laughter which may follow.

Hey guys, it's not like I pretended to know anything, so be gentle on me.