Loop or String Theory

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Loop Theory vs. String Theory. Your thoughts.

Gimme them oscillating strings!! Read Greene's The Elegant Universe?

They both have their strengths and weaknesses. Personally I'm in favor of quantum loop theory, it does at least offer some hope of testing it in the near future.


String theory requires a particle accelerator the size of the solar system, and has too many solutions...


Here's a link to some of the most recent updates on Quantum Loop Theory from the Plenary talks recently. It also includes audio as well as PDF files, and its recommended to follow along as you can easily get lost, especially if the material is difficult. Especially pay attention to Martin Reuter's slides and audio and Lee Smolin's:

http://www.matmor.unam.mx/eventos/loops07/plen_abs.html

I hope this isn't over your head .........

Yes I have, and it isn't very detailed, much more geared to the general population. Plus, it has some gross inaccuracies due to the fact that the material in there is way oversimplified.

Last edited by RadiantAspie on 11 Oct 2007, 5:05 pm, edited 1 time in total.

Thank you. I shall investigate this material.

Actually one of my main areas of interest is quantum computation, which brushes against this.

I'm reading Greene's book. It seems a good book for the general public. I don't know anything about physics. Has anyone read "The Fabric of Cosmos" or "The Cosmic Landscapes", they also seem to be good books.

Right now we don't have the technology to test this theory thoroughly. Until we do, it remains in the sphere of speculation.

ruveyn

Here is a speach by Brian Greene in TED talks: http://www.youtube.com/watch?v=YtdE662e ... re=channel
According to him in the near future we will be able to test the existence of multiple dimentions implied by string theory.

Neither. We don't know enough about the universe to come up with a theory of everything; such talk was going on toward the end of the 19th century...then radiation put an end to those attempts. Relativity also. Quantum theory. Now we're trying to unify all these forces again?

In order to even begin to develop a theory of everything, one must know everything; we don't even know what "everything" is, so we have nothing compare our knowledge to. What we know so far is simply what we know so far.

Regardless of what theory gains prominence, a phenomenon it didn't account for will be discovered.

In that case you might want to take a look at the following paper:

http://arxiv.org/abs/hep-th/0501068

Unfortunately this is still far from a confirmation of string theory because in terms of AdS/CFT correspondence we still don't know which string theory corresponds exactly to QCD. There are plans to test AdS/CFT correspondence along with other things at the LHC. Remember that just about any theory of quantum gravity will be difficult to test due to the weakness of gravity.

Loop quantum gravity has its own problems just as string theory does and I'm personally not convinced its the right approach. But then again, I could be wrong.

-Jonathan

The so-called theory of everything is really not about everything. It is a theory that unifies the four know forces or interactions: electromagnetic. strong force, weak force and gravitational interaction. Even if we had such a theory here and now it would not give us the last word on how living systems work, for example.

We are probably not smart enough to reduce every physical system (that includes living matter) to a basic elementary set of causes.

There are physical processes that we do not understand fully, especially turbulence and other non-linea chaotic dynamical systems. Our problem is we have three pound brains. They are good enough for aiming rockes and shagging fly balls. Our brains are not very good at grasping turbulent systems which is why we haVe problems modeling weather and climate. To do turbulence in our heads we would need thirty pound brains.

ruveyn

Ruveyn

Whenever I see some of your posts, I get the impression that you might be a retired physicist. What career did you have before your retirement? I'm just interested.