Basic question in electromagnetic duality

In summary, the relationship between the electromagnetic duality tensor $G^{\mu\nu}$ and the electric induction $D$ and magnetic intensity $H$ is that the components of $G^{\mu\nu}$ are equivalent to the components of the electric and magnetic fields. This can be proven through a comparison of the equations and a definition of the electric and magnetic fields in terms of $G^{\mu\nu}$.
  • #1
PhyAmateur
105
2
We originally have $$\overrightarrow{\nabla}\cdot\overrightarrow{B} = 0$$

$$\overrightarrow{\nabla}\times\overrightarrow{E} = -\frac{\partial \overrightarrow B}{\partial t}$$

When electromagnetic duality is concerned this rank 2 tensor kicks in:$$G^{\mu\nu}$$

And most of books and sites define $$D_i = G_{i0}$$ and $$H_i = 1/2 \epsilon_{ijk}G_{jk}$$
My question is why is this $$G^{\mu\nu}$$ related to our previously known electric induction D and magnetic intensity H?
In other words,how comes that $$G^{\mu\nu}$$ this new notion that rised after duality came in related to our old notion of electric induction D and magnetic intensity H?
 
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  • #2
I'm looking for a strong mathematical proof that shows the relation between them.Any help would be appreciated!Thanks in advance!A:In general, if you have a tensor $T^{\mu\nu}$, and you don't already know what it is, then the only way to find out is by looking at the components. If you look at the components of the electromagnetic duality tensor you find that it has the form $$G^{\mu\nu} = \left( \begin{matrix} 0 & D_x & D_y & D_z \\ -D_x & 0 & H_z & -H_y \\ -D_y & -H_z & 0 & H_x \\ -D_z & H_y & -H_x & 0 \end{matrix} \right).$$This should remind you of the components of the electric and magnetic fields. To make this comparison you can let $E_x = -D_x, E_y = -D_y, E_z = -D_z, B_x = H_z, B_y = -H_x, B_z = H_y$. It is easy to check that this definition satisfies the equation $E_i = \epsilon_{ijk}B_j$ and so you can conclude that $G^{\mu\nu}$ is related to the electric and magnetic fields in the way you expected it to be.
 

1. What is electromagnetic duality?

Electromagnetic duality is a fundamental concept in physics that describes the symmetry between electric and magnetic fields. It states that the equations governing the behavior of electric and magnetic fields are interchangeable, meaning that the same physical phenomena can be described in terms of either electric or magnetic fields.

2. How does electromagnetic duality impact our understanding of electromagnetism?

Electromagnetic duality provides a deeper understanding of the relationship between electric and magnetic fields, allowing us to view them as two sides of the same coin. This concept has led to the development of new theories and models that have greatly advanced our understanding of electromagnetism.

3. Can you give an example of electromagnetic duality in action?

One example of electromagnetic duality is the phenomenon of duality in superconductors. In type I superconductors, the magnetic field is expelled from the material, while in type II superconductors, the magnetic field is allowed to penetrate the material in the form of quantized vortices. This duality between the two types of superconductors is a result of electromagnetic duality.

4. What are the practical applications of electromagnetic duality?

Electromagnetic duality has numerous practical applications in various fields such as electronics, telecommunications, and materials science. It has also been instrumental in the development of technologies such as superconductors, MRI machines, and particle accelerators.

5. Are there any open questions or debates surrounding electromagnetic duality?

While electromagnetic duality is a well-established concept, there are still ongoing debates and research surrounding its implications and applications. Some scientists are exploring the possibility of duality in other physical phenomena beyond electromagnetism, while others are investigating the role of duality in understanding the fundamental nature of the universe.

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