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Mentat
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Ok, I know about the search for supersymmetric partner particles (sparticles) and the tests on gravity variance at small scales, but what other tests are there that can be used to add proof to superstring theory?
Originally posted by notevenwrong
Neither of the two tests you mention are evidence for string theory. For this to be true string theory would have to predict some properties of sparticles or deviations from Newton's laws. You won't find any such predictions. And you won't find any others. String theory is not a theory, it is a hope that a theory exists. Unless this hope can be realized, you don't have a theory, and as for predictions, there are none, nada, zip.
Originally posted by Mentat
Well, I can't think of any now, except that one of them had to do with black holes and Hawking radiation...I'll get back to you on that. [/B]
In the search for a TOE (theory of everything), we precisely search for principles that apply in every circumstance whatsoever. In one sense it is a tautology of nature, inherently true for every interpretation that nature can provide. And perhaps like a tautology, a TOE would be impossible to prove wrong. So what's the complaint?Originally posted by marcus
One interesting take on this is that since string theory makes no firm predictions it is impossible for any experimental evidence to either affirm or deny it. In other words the theory is so vague and multifarious that it cannot be either right or wrong. From this standpoint, it would be an improvement if the theory could be made definite enough to prove wrong but, so far, this has not been done.
Originally posted by Mike2
In the search for a TOE (theory of everything), we precisely search for principles that apply in every circumstance whatsoever. In one sense it is a tautology of nature, inherently true for every interpretation that nature can provide. And perhaps like a tautology, a TOE would be impossible to prove wrong. So what's the complaint?
Originally posted by marcus
I just don't find string mathematically or scientifically interesting.
It might help to think in terms of how the universe started to begin with. For examples if everything started from a singularity, did it grow continuously, or did it grow in quantum leaps, or were other points added adjacent to the first point? I can't think of any other options.Originally posted by marcus
Mike, what I find interesting is the issue of what is space.
I strongly suspect it isn't a subset of an Euclidean or Minkowski continuum.
I suspect that space is not a differentiable manifold.
Originally posted by Mike2
...
If it grew continuously, then of course space is a continuum. If it grew in quantum leaps, then there is usually some equation on continuous variables that give rise to these quantum states. If other points were simply added to the first, then there needs to be some sort of continuum to communicate the state of one point to the next. ...
How are these quantum states determined if not by use of some diff eq on continuous variables. So there must exist some continuous variable somewhere. Perhaps you are suggesting that physical quantities are some sort of transformation of some other continuous space.Originally posted by marcus
BTW the quantum evolution of the universe is followed by Bojowald
in several papers and it does, as you visualized, proceed in "jumps"
of the variables like volume, density, curvature, scalefactor
and as you might imagine these jumps are very tiny
Originally posted by Mike2
How are these quantum states determined if not by use of some diff eq on continuous variables. So there must exist some continuous variable somewhere. Perhaps you are suggesting that physical quantities are some sort of transformation of some other continuous space.
Originally posted by marcus
He shows you the quantized Einstein or Friedmann equation and it is a difference equation (time goes in tiny discrete steps)
and what the difference equation predicts is the same
(in the limit) as the WheelerDeWitt and ultimately the Friedmann differential equation.
You say "there must be a continuous variable somewhere" and I you are right. down at a microscopic level things are discrete but in the limit (after hundreds of timesteps) things look continuous
so the continuity you want is in the large scale limit
I'd like to know the prerequisits of these papers you mention.[should I get some links for some Bojowald papers? he has some for more specialized audience and some for wider audience. If you want I will get 2 or 3 links and you can take your pick (or maybe you have the links already)
Originally posted by Mike2
So does he simply start with the assumption of discrete time steps, etc so he can use difference equations instead of differential equation?
...does he justify the assumption of discrete time?
Originally posted by Mentat
but what other tests are there that can be used to add proof to superstring theory?
jeff,I agree on this one.jeff said:There are many amazing examples of this sort of thing in string theory. This connection between geometry and gauge theory is very deep and is not yet completely understood, but is nonetheless affecting our perspective on and promises to deepen our understanding of gauge theories in ordinary quantum field theory. Anyone who dismisses this as "uninteresting" is probably too warped to take seriously.
compactification is put in by hand, 10 dimensional Minkowski space is stable.selfAdjoint said:All the branes and compacted manifolds and all the rest of it result from working through the results of that starting point.
Superstring Theory is a theoretical framework that attempts to explain the fundamental laws of nature by describing all particles and forces in the universe as vibrations of tiny, one-dimensional strings. This theory combines concepts from both quantum mechanics and general relativity in order to unify the four fundamental forces of nature: gravity, electromagnetism, strong nuclear force, and weak nuclear force.
There is currently no direct experimental proof for Superstring Theory. However, there are several mathematical and theoretical arguments that support the validity of this theory. These include the ability to explain the existence of gravity, the unification of the four fundamental forces, and the ability to incorporate the principles of quantum mechanics and general relativity.
Because Superstring Theory is a highly complex and abstract theory, it is difficult to test directly. However, scientists have proposed several indirect methods for testing this theory, such as studying the properties of superpartners (particles predicted by the theory) and looking for evidence of extra dimensions in particle collisions. Additionally, advancements in technology and experimental techniques may provide new ways to test the predictions of Superstring Theory in the future.
The variance in Superstring Theory refers to the different versions or interpretations of the theory that have been proposed by different researchers. These variations arise from different assumptions and approaches to the mathematical equations that describe the theory. Some of the major variations include Type I, Type II, and heterotic string theories, as well as M-theory.
No, there are other theories, such as loop quantum gravity and supersymmetry, that also attempt to unify the four fundamental forces. One of the main challenges for scientists is to find a way to test and ultimately choose between these competing theories in order to determine which one best explains the fundamental laws of nature.