How many dimensions are needed to fully describe the electromagnetic force?

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Discussion Overview

The discussion revolves around the dimensionality required to fully describe the electromagnetic (EM) force, exploring whether four dimensions are sufficient or if additional dimensions are necessary to account for aspects like polarization and twist. The scope includes theoretical considerations and mathematical representations related to electromagnetism.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • Some participants assert that Maxwell's equations operate within four dimensions, questioning if more dimensions are needed for a complete description of the EM force, particularly regarding polarization and twist.
  • One participant notes that the electromagnetic field is a massless vector field with two independent degrees of freedom, suggesting that higher spacetime dimensions could be considered for exploring unitary representations of the Poincare group.
  • Another participant emphasizes that polarization and twist may already be encompassed within Maxwell's equations, indicating that the dimensionality required depends on the specific context and goals of the analysis.
  • A later reply clarifies that if the discussion pertains to the Lorenz force, four dimensions may suffice, but for more complex scenarios, such as internal forces in a two-body covariant system, additional dimensions may be necessary, citing examples like Stuckelberg theory which involves higher-dimensional phase spaces.

Areas of Agreement / Disagreement

Participants express differing views on the necessity of additional dimensions beyond four for a complete description of the EM force, indicating that the discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Limitations include varying interpretations of what constitutes a complete description of the EM force, dependence on specific definitions of forces, and the potential for different mathematical frameworks to yield different dimensional requirements.

PatrickPowers
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Maxwell's equations use four dimensions. But wouldn't we need more dimensions to completely describe the EM force. I'm thinking of polarization and twist. So how many mathematical dimensions are necessary for a complete description? That is, how big do the matrices need to be and how many degrees of freedom do they have.
 
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The electromagnetic field is a massless vector field, which means that the free field has two independent physically relevant field degrees of freedom. Of course, spacetime has four dimensions. One could think about fields in higher spacetime dimensions, i.e., look for the unitary representations of the Poincare group in more than four dimensions.
 
I'm thinking of polarization and twist.
... are not twist and polarization included in Maxwell's equations? Look how they come about!

Of course, you can represent anything you like in as many dimensions as you like.
Depends what you want to do with it.

@vanhees71: I was kinda interpreting the question to be asking about the minimum number of dimensions needed to completely describe all of E-Mag. I still think that's 4 - though it is possible to do it in any number like you say.

We can also do it in less for specific situations with a lot of symmetry.
 
PatrickPowers said:
Maxwell's equations use four dimensions. But wouldn't we need more dimensions to completely describe the EM force. I'm thinking of polarization and twist. So how many mathematical dimensions are necessary for a complete description? That is, how big do the matrices need to be and how many degrees of freedom do they have.

It depends what you mean by «EM force«. If you mean the old Lorenz force, then 4D are enough. If you mean more general forces (e.g. the internal force in a two-body covariant system) then you must go beyond Maxwell and special relativity. For instance the EM forces in Stuckelberg theory are defined in a 8N dimensional phase space. For a two-body system, the force is a function in 16 dimensions.
 

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