Questions tagged [skyrmion]

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Topological Charge: How to see that it is integer?

I am currently studying topological solitons. But the concept of topological charge still puzzles me. I see that the topological charge measures how much area of the image space the field ...
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What is the difference between a skyrmion and a magnetic vortex?

Skyrmions and magnetic vortices are spin structures occurring in magnets. What are the differences between them? More specifically, I would like to understand their origin and how to distinguish them.
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69 views

A primer on topological solitons in scalar field theories

As the title suggests I want to learn more about topological solitons in scalar field theories. I am searching for a resource which is self-contained, in the sense that it also explains the ...
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71 views

How does the Mermin-Ho theorem handle singularities arising from the hairy ball theorem?

I am reading about the derivation of the Mermin-Ho relation in chapter III. B of (Kamien, 2002) and trying to understand how it fits with the hairy ball theorem. Assuming you have a unit vector $\hat{...
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43 views

What is physical significance of $k$-space topology?

I am working with topological materials and I do understand what topology is. While reading papers, I am not able to understand the "nontrivial k-space topology". How skyrmions are mostly ...
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How "hedgehog" or instanton event changes the configuration of neel vector in 2D antiferromagnet?

The definition of "hedgehog" or instanton event here is "a space-time event where the skyrmion number Q changes by $\pm1$ is called a hedgehog" (ref.1 & 2). A nice figure ...
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1answer
486 views

Skyrmion number

The skyrmion number is defined as $$n=\frac{1}{4\pi}\int\mathbf{M}\cdot\left(\frac{\partial\mathbf{M}}{\partial x}\times\frac{\partial\mathbf{M}}{\partial y}\right)dxdy$$ where $n$ is the topological ...
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What are Skyrmion bubbles?

what exactly is the difference between a skyrmion and a skyrmion bubble? Thanks.
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43 views

How to derive the Einstein-Skyrme equations?

I would like to derive the Einstein-Skyrme equations. The action can be read as \begin{equation} S[g,U] = \int d^{4}x\sqrt{-g}\biggl[R + \frac{K}{4}Tr\bigg(A^{\mu}A_{\mu} + \frac{\lambda}{8}F_{\mu\...
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1answer
211 views

What does topologically stable mean?

I am working on an article about skyrmion manipulation and it is written that those particles are "topologically stable particle-like spin configurations that carry a characteristic topological charge ...
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No global monopoles in QCD

If a global symmetry gets both spontaneously and explicitly broken, the explicit symmetry breaking pattern is crucial for understanding the formation of topological defects. For example, in the axion ...
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105 views

Number of baryons in the Skyrme model

In QCD, the Eightfold Way organizes the number of baryons with respect to their flavor and color quantum numbers: for three light $(u,d,s)$ quark constituents, a spin-(1/2) baryon octet and a spin-(3/...
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Skyrmion of pseudo-scalar mesons and vector mesons

I had heard statements that Skyrmion of pions (pseudo-scalar mesons) cannot be an object like baryon, however, Skyrmion of vectors mesons may indeed form an object like baryon. For example, see this ...
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684 views

Non-chiral skyrmion v.s. Left/Right chiral skyrmion

A skyrmion in a 3-dimensional space (or a 3-dimensional spacetime) is detected by a topological index $$n= {\tfrac{1}{4\pi}}\int\mathbf{M}\cdot\left(\frac{\partial \mathbf{M}}{\partial x}\times\frac{...
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866 views

half Skyrmion vs Meron

Is there a difference between a half skyrmion and a meron? I'm asking this in regard to half skyrmion theories of High Tc Superconductors. It would be interresting to know if the proposed half ...