Strings vs Blocks: Dimensions & Oscillating Volumes

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Discussion Overview

The discussion revolves around the dimensionality of strings and branes in theoretical physics, particularly in the context of string theory and the implications of using oscillating volumes versus one-dimensional strings. Participants explore the mathematical and physical reasoning behind these concepts, as well as the challenges associated with higher-dimensional objects.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants question why strings are considered one-dimensional and whether branes can have two dimensions, suggesting that oscillating volumes like cubes are not utilized.
  • Others propose that the symmetry and minimization of energy might explain why certain shapes are preferred in theoretical models, comparing it to the shape of celestial bodies.
  • There are claims that extending objects into more dimensions leads to issues with ultraviolet divergences that cannot be resolved perturbatively, which is argued to be a unique characteristic of one-dimensional extensions.
  • Some participants mention the concept of n-branes and express uncertainty about how to quantize them consistently.
  • It is noted that while theories involving more dimensions exist, the complexity of the mathematics increases significantly with additional dimensions.
  • There is a discussion about the practical use of n-branes by string theorists, who reportedly treat them as classical objects despite the theoretical challenges.

Areas of Agreement / Disagreement

Participants express a range of views on the dimensionality of strings and branes, with no consensus reached on the fundamental reasons behind the preference for one-dimensional strings over higher-dimensional objects. The discussion remains unresolved regarding the quantization of n-branes and the implications of using higher-dimensional objects in string theory.

Contextual Notes

Limitations include the unresolved nature of the mathematical frameworks for higher-dimensional objects and the dependence on specific definitions of dimensionality in string theory. The discussion reflects varying levels of understanding among participants regarding complex theoretical concepts.

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Why do strings only have one dimension (or maybe branes have 2 dimensions)? Why aren't oscillating volumes (like a cube) used?
 
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Symmetry and minimization of energy.

Your question is a good one, and one I think any intelligent person should ask themselves at some point. It's actually somewhat equivalent to saying "why isn't the Sun a cube, or hexahedron?"
 
Pjpic said:
Why do strings only have one dimension (or maybe branes have 2 dimensions)? Why aren't oscillating volumes (like a cube) used?
If strings are replaced with objects extended in more dimensions, then ultraviolate divergences cannot longer be removed (at least not perturbatively). This happens only for extension in 1 dimension.
 
whats about n-branes?
 
I agree it is a good question and the answer lies in mathematics.

There is no reason why theories involving more dimensions cannot be devised (and indeed they have already) but the mathematics involved becomes increasing more complex as you add more dimensions.
 
Dmitry67 said:
whats about n-branes?
It is still not known how to quantize them consistently.
 
Demystifier said:
If strings are replaced with objects extended in more dimensions, then ultraviolate divergences cannot longer be removed (at least not perturbatively). This happens only for extension in 1 dimension.

I don't know what it means, but thanks for the answer. So, string theory says that objects can only have one dimension due to a fundamental property of reality?
 
Demystifier said:
It is still not known how to quantize them consistently.

Hmm, but string theorists use them regularly anyway don't they?
 
Coin said:
Hmm, but string theorists use them regularly anyway don't they?
Yes. They mostly use them as classical objects.
 
  • #10
Demystifier said:
Yes. They mostly use them as classical objects.
Very interesting, thanks.
 

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