Local Electrodynamics in higher dimensions?

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Discussion Overview

The discussion revolves around the concept of local electrodynamics in higher dimensions, exploring the implications of Maxwell's equations and their applicability at very small length scales. Participants consider theoretical frameworks, such as string theory, and the geometric interpretation of spacetime in relation to electrodynamics.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant suggests that Maxwell's equations may only be valid in (3+1)-dimensional spacetime and could break down at very small scales.
  • Another participant proposes that the lack of observed gravitons might be due to their escape into higher dimensions after traveling short distances.
  • There is a mention of string theory's approach, which involves curling extra dimensions tightly.
  • One participant questions whether the infinities in electrodynamics (ED) and quantum electrodynamics (QED) are solely due to point charges and if local geometry could mitigate these issues.
  • A later reply asserts that the infinities in QED are not exclusively problematic for point charges.
  • Another participant speculates on the idea that "curled up" dimensions could be represented by a vector or fiber bundle at a point in spacetime, with point charges viewed as loops in the bundle projecting down to a point.

Areas of Agreement / Disagreement

Participants express a range of views on the implications of higher dimensions for electrodynamics, with no consensus reached on the validity of the proposed ideas or their implications for existing theories.

Contextual Notes

Some limitations include the dependence on specific definitions of dimensions and the unresolved nature of the mathematical implications of the proposed models.

"pi"mp
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Local Electrodynamics in higher dimensions??

So I am an unexperienced undergrad but the other day I had a few thoughts which are most likely crazy. I'm just wondering why they don't work. And whether the questions I'm asking are answered elsewhere.

So I've heard:

(i) Maxwell's equations break down on very, very small length scales. But Hermann Weyl showed they only work in (3+1)-dim spacetime.

and

(ii) Perhaps we haven't observed gravitons because they escape to higher dimensions after traveling only tiny length scales.

So I was wondering, is there some geometric way of thinking of the universe where locally, the universe is a higher dimensional space and they dimensions somehow coalesce or "smooth out" into the usual (3+1)-dimensions at larger lengths? Might Maxwell's electrodynamics be only approximate but break down locally?

I might not even be asking sensible questions and I certainly don't know enough mathematics to ask it more concisely, but any thoughts would be appreciated.
 
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It's pretty much what string theory does ... what you do is curl the extra dimensions up real tight.
 
ah thank you...so the infinities that plague ED and QED, aren't these only problematic with point charges? Does the local geometry fix this?
 
No - the infinities that plague QED are not only problematic for point charges.
 
So thinking about my original post more now that I know more geometry, is the idea that the dimensions that you say are "curled up" locally, are from a vector or fibre bundle at that point on spacetime? Then the problematic point charges can be regarded as loops in the bundle but project down to a point still.
 

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