Can Kaluza-Klein theory accommodate magnetic charge?

Click For Summary

Discussion Overview

The discussion centers on whether Kaluza-Klein theory can accommodate magnetic charge, exploring the geometric differences between electric and magnetic charge within this theoretical framework. Participants delve into the implications of topological twisting of S^1 and its relation to magnetic charge, as well as the broader consequences for the validity of Kaluza-Klein theory.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants suggest that Kaluza-Klein theory can accommodate magnetic charge, referencing Professor Gary Horowitz's work.
  • There is a discussion about the concept of topological twisting of S^1, with participants attempting to clarify its meaning and implications for magnetic charge.
  • One participant proposes a scenario involving a magnetic charge at the origin of a coordinate system and questions the nature of topological twisting in this context.
  • Another participant challenges the idea of a special origin in a cosmological context, arguing that it complicates the discussion of physics in a homogeneous universe.
  • Concerns are raised about the implications of Kaluza-Klein theory allowing for magnetic charge, with some arguing it could be seen as a weakness of the theory due to the lack of observed magnetic monopoles in nature.
  • Links to external resources are shared, indicating a search for simpler explanations of the concepts discussed.

Areas of Agreement / Disagreement

Participants express differing views on the implications of magnetic charge within Kaluza-Klein theory, with some supporting its accommodation and others questioning the validity of the theory if it does. The discussion remains unresolved regarding the nature and significance of topological twisting of S^1.

Contextual Notes

Participants highlight the complexity of the concepts involved, including the assumptions about the nature of space surrounding magnetic charges and the implications of isotropy and homogeneity in cosmological models.

Spinnor
Gold Member
Messages
2,228
Reaction score
419
Can Kaluza-Klein theory accommodate magnetic charge? If so is there a simple geometric difference between electric and magnetic charge in such a theory?

Thanks!
 
Physics news on Phys.org
So if you can believe Professor Gary Horowitz the answer is yes and the geometrical picture is,

upload_2016-7-24_11-22-9.png


From,

Microstates of Kaluza-Klein Black Holes

From Google,

https://www.google.com/search?q=kal...webhp&ei=5c-UV7LqEsP--AGT8ZLICg&start=10&sa=N

Not sure what topological twisting of S^1 means?

Thanks!
 

Attachments

  • upload_2016-7-24_11-21-29.png
    upload_2016-7-24_11-21-29.png
    60.9 KB · Views: 576
Spinnor said:
Not sure what topological twisting of S^1 means?

I will take a stab at this. So we have a circle at each point of Minkowski space, S^1. Say at the origin we have magnetic charge. Suppose we now make one full orbit of this charge in the plane z = 0. Suppose that when we come back to where we started in the z = 0 plane in the compact space we have advanced or retarded by one full turn in the space S^1? Is that what topological twisting of S^1 means?

The magnetic charge is the topological twisting?

There is something else we could do. Suppose we take the circular fibers, give them a cut and then glue the ends at different points of our base space, let each pair of ends of all the circles be separated by the same small spacetime vector? Once around the fiber and we do not come back to where we started in space or even time. Is that an operation that gives a topological twisting of S^1?

Thanks!
 
Last edited:
I'm not sure what topological twisting of a circle means.
This might be a good starting point http://www.itp.ac.cn/~gaoyh/doc/tt1.pdf (I'll try to have a detailed look at this tomorrow)

The following statement is fishy though
Spinnor said:
Say at the origin we have magnetic charge.

You want the resulting space (4D Minkowski) to behave as if it were cosmological in nature i.e. you cannot choose a unique point to represent the origin.
It would be like saying that the Earth's position is special compared to the rest of the universe.

If we allow such an origin it would be hard to talk about "our physics" unless I'm attributing too much importance to isotropy/homogeneity.
 
JorisL said:
The following statement is fishy though

I was not clear then. I am suggesting that we look at the space surrounding a point magnetic charge and for simplicity let us place it at the origin of some coordinate system, just as we could place a point charge at the origin. There are only so many ways one can topologically twist the fibers S^1?

( And there has to be a whole lot of symmetry in the twisting of the fibers S^1, the symmetry of a point magnetic charge?)

Thanks for the link!
 
That raises a question, what is the lowest dimension Kaluza Klein theory that magnetic charge can exist? Can one assume that magnetic charge is still a topological twisting of S^1?

Thanks!
 
If Kaluza Klein did allow magnetic charge, that would be an argument against the theory (as no such thing is observed in Nature) rather than a point in its favor.
 
  • #10
ohwilleke said:
If Kaluza Klein did allow magnetic charge, that would be an argument against the theory (as no such thing is observed in Nature) rather than a point in its favor.

But the theory apparently does have room for magnetic charge, which is cool.

Do you by chance know what is meant by a "topological twisting" of the fibers S^1?

Thanks!
 

Similar threads

  • · Replies 12 ·
Replies
12
Views
5K
  • · Replies 0 ·
Replies
0
Views
536
  • · Replies 13 ·
Replies
13
Views
1K
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 5 ·
Replies
5
Views
5K
  • · Replies 9 ·
Replies
9
Views
4K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 3 ·
Replies
3
Views
3K