What kind of local topological "particles" can you get in R3?

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SUMMARY

This discussion explores the types of local topological "particles" that can exist in three-dimensional space (R3), building on concepts from two-dimensional surfaces (R2). The participants identify several potential structures, including 3D cross-caps, wormholes, and toroidal configurations, all of which are posited to contribute negative curvature to the surface. The conversation also raises questions about the existence of non-orientable topological defects within General Relativity and their potential behavior as fermions. Additionally, the concept of chiral topological particles and their relationship to string theory is examined.

PREREQUISITES
  • Understanding of topological surfaces, specifically cross-caps and handles.
  • Familiarity with General Relativity and its implications for topological defects.
  • Knowledge of toroidal structures and their properties in topology.
  • Basic concepts of string theory and its relation to topology.
NEXT STEPS
  • Research the classification of 3D manifolds and their topological properties.
  • Study the implications of Dehn Surgery in topology.
  • Explore the relationship between topology and General Relativity, focusing on non-orientable defects.
  • Investigate the concept of chiral topological particles and their potential applications in theoretical physics.
USEFUL FOR

This discussion is beneficial for mathematicians, theoretical physicists, and researchers interested in topology, General Relativity, and the intersection of these fields with particle physics.

nuclearhead
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I know the solution for R2. That is a for an infinite plane you can have one of 2 things (from the classification of 2D surfaces):

1) cross cap (cut a circle out of the plane and identify opposite points).
2) a oriented handle (cut two circles out and identify points on one with reflected points on the other - like a wormhole)

A non-oriented handle (cut two circles out and identify points on one with equivalent points on the other) is equivalent to two cross-caps.

Each of these "particles" adds negative curvature to the surface.

So that got me thinking, in R3 what kind of topological "particles" could you get?

I think there will be more since you can cut out spherical holes or toroidal holes (which could be knotted). You could get 3 dimensional equivalents of (1) and (2) but can you get anything else interesting? And will they all add negative curvature?

The ones I can think of are:

1) Cut out a spherical hole and identify opposite points (a 3D cross-cap - whatever that is called!)
2) Cut out two spherical holes and identify reflected points (like a wormhole)
3) Cut out a torus (perhaps knotted) and identify opposite points at each cross-section.
4) Cut out a torus (perhaps knotted) and identify opposite points but reflected
5) Cut out two tori and identify points - (Like a toroidal wormhole - not sure if this can be composed of others)

I know the wormholes (2) are solutions of General Relativity. Are any of the others? Does that mean that these things exist or not? Are non-orientable topological defects allowed in General Relativity? If so, would they act like fermions?

Also, can there be any chiral topological particles? Maybe made out of a trefoil knotted torus or something simpler?

Would something like (3) act like a string from string theory or something else? What is their curvature? I imagine it is zero. Hence they might be solutions to empty space in GR.

In 2D space there is no-such thing as an anti-topological particle, since two cross-caps don't cancel each other out, they produce a non-oriented handle. (Being negatively curved they just add together). Are there any such things as anti-toplogical particles in 3D? (i.e. if both particle and anti-particle exist on the same plane it is equivalent to R3).

Sorry, lots of questions! This was just on my mind today!
 
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I've thought of some more.

If you cut out a toroidal knot, and create a fibration of the knot with circles (e.g. decompose the torus into circles) then you can identify opposite points in these circles.
The circles will loop N times around the major circle and M times around the minor circle so there should be lots of topological particles for each toroidal knot labelled by (N,M) where N and M are integers.

But I don't know how to check how many of these are identical. I suppose you'd need the Poincare theorem for that(?)

Edit: Oh seem I just reinvented Dehn Surgery. haha.
 
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