String Theory Predictions: Beyond QT, SR & GR

In summary, string theory makes experimental predictions that differ from past theories such as quantum theory, special relativity, and general relativity. It proposes the existence of 1D vibrating strings that are too small to be detected, which give rise to countless particle types that have yet to be discovered. String theory also predicts the existence of extra dimensions, but they are too small to be detected. M theory, which is a version of string theory, suggests that there are larger extra dimensions that may be testable, but so far there is no evidence to support this. However, recently there have been claims of string traces in advanced proton decay experiments. While there are other ways to evaluate a theory, such as its plausibility and consistency, string
  • #1
PRodQuanta
342
0
What kind of experimental predictions does String theory make that differs from the predictions that past theories (QT, SR, GR)make?
Paden Roder
 
Physics news on Phys.org
  • #2
None.

That is, nothing testible. String theory replaces the point particle with vibtrating 1D loops or lines, which however are too small for us to be able to verify. Since the various vibrations of the string is what gives us the zoo of elementary particles, there should be countless particle types that exist - but have not yet been discovered. String theory also predicts the existence of additional dimensions, but they are also too small to be detected. How convenient for string theorists.

M theory allows for the existence of larger extra dimensions that should be testible, but so far nothing has come of it.
 
  • #3
I have heard that recently, Ed Witten has stated that there are string traces in advanced proton decay experiments. What do you think of this?
Paden Roder
 
  • #4


Originally posted by sol
What about "distance" when it comes to measuring gravity?

You mean how the inverse square law should fall off as we probe smaller scales?
 
  • #5
Guy's,

Keep in mind that there are other ways than experimentally to differentiate between viable and pathological theories. In particular, we can ask whether a theory can be reconciled with what we already know and whether it's internally consistent. In the case of string theory the answer to both questions is yes. On the other hand, as far as we know, the answer with respect to LQG continues to be no. We can also ask about the plausability of a theory's basic assumptions. For example, the pattern of discovery with particle accelerators is that going to higher energies produces previously unseen phenonmena requiring reevaluation of current theory. Then given that we've only probed at energies which are a tiny fraction of the Planck energy, how plausible is the idea that no new phenomena will emerge invalidating GR as a basis for quantization before we hit Planck energies? Not very.

For example, SMT (String/M-theory) correctly produces the black hole entropy relation, LQG doesn't. Despite that fact that LQG was constructed to be a background independent QGT, the only thing it appears to be is a background independent theory of something we know not what, but it's a virtual certainty that "what" has nothing to do with our universe. On the other hand, any consistent string theory must contain the graviton and GR and in this sense not only is it our only genuine QGT, it aclually predicts (or more accurately retrodicts) spacetime itself!
 

1. What is string theory?

String theory is a theoretical framework that attempts to explain the fundamental nature of particles and their interactions. It proposes that the building blocks of the universe are not point-like particles, but rather tiny, vibrating strings.

2. How is string theory different from quantum mechanics, special relativity, and general relativity?

String theory goes beyond these well-established theories by attempting to reconcile their differences and provide a unified framework for understanding the universe at both the microscopic and macroscopic levels. It also includes the concept of extra dimensions, which are not present in these other theories.

3. What are some predictions of string theory?

One of the major predictions of string theory is the existence of supersymmetry, a symmetry between particles with different spins. It also predicts the existence of extra dimensions, which could help explain the weakness of gravity compared to the other fundamental forces.

4. How can string theory be tested?

Currently, string theory cannot be tested directly as it requires energies much higher than what is currently achievable. However, some of its predictions can be tested indirectly, such as the existence of supersymmetry and the effects of extra dimensions on the behavior of particles.

5. Is string theory widely accepted by the scientific community?

String theory is a highly debated topic in the scientific community and does not have a consensus. While some physicists believe it is a promising avenue for understanding the fundamental laws of the universe, others criticize it for lacking experimental evidence and being too mathematically complex.

Similar threads

  • Beyond the Standard Models
2
Replies
60
Views
5K
  • Beyond the Standard Models
Replies
31
Views
2K
  • Beyond the Standard Models
Replies
26
Views
482
  • Beyond the Standard Models
Replies
28
Views
2K
  • Beyond the Standard Models
Replies
3
Views
1K
Replies
47
Views
4K
  • Beyond the Standard Models
Replies
13
Views
1K
  • Beyond the Standard Models
Replies
2
Views
2K
  • Beyond the Standard Models
2
Replies
40
Views
5K
  • Beyond the Standard Models
Replies
24
Views
3K
Back
Top