How Do the E and B Fields Transform Through Rotation and Boost?

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The discussion focuses on transforming the electromagnetic field tensor (E and B fields) through rotation around the y-axis and a boost along the z-axis. The transformation is expressed using the equation F'_{\mu\nu}=\Lambda^\mu_\rho \Lambda^\nu_\sigma F_{\rho\sigma}, with the rotation matrix provided for the y-axis. The user encounters difficulties with matrix multiplication, noting that the resulting tensor is not anti-symmetric, which is necessary for extracting the required information. Clarification is sought on whether to use the inverse of the transformation matrix when transforming a covariant tensor. The user contemplates the implications of rotating by either +theta or -theta.
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Homework Statement


So, I'm asked to find how the fields (E, and B) transform by transforming the electromagnetic field tensor.

The transformations are a) rotation around y axis, and b) boost along z.

Homework Equations



F'_{\mu\nu}=\Lambda^\mu_\rho \Lambda^\nu_\sigma F_{\rho\sigma}

The Attempt at a Solution



So, doing part a) I think the above equation should be right...and for the transformation matrices, I just put the rotation around y:

\Lambda^\mu_\nu =\begin{bmatrix} 1&0&0&0 \\ 0&cos(\theta)&0&sin(\theta)\\0&0&1&0\\0&-sin(\theta)&0&cos(\theta) \end{bmatrix}

I trid just doing the matrix multiplication twice, but that can't be right because the answer I get is not anti-symmetric (and so I can't extract the information I need). Does the equation above not represent matrix multiplying twice? I thought it did since the transformation for a 4-vector is simply matrix multiplication once.

The answer does not seem to be just:

F'_{\mu\nu}=\begin{bmatrix} 1&0&0&0 \\ 0&cos(\theta)&0&sin(\theta)\\0&0&1&0\\0&-sin(\theta)&0&cos(\theta) \end{bmatrix}(\begin{bmatrix} 1&0&0&0 \\ 0&cos(\theta)&0&sin(\theta)\\0&0&1&0\\0&-sin(\theta)&0&cos(\theta) \end{bmatrix} \begin{bmatrix} 0&E_x&E_y&E_z \\ -E_x&0&-B_z&B_y\\-E_y&B_z&0&-B_x\\-E_z&-B_y&B_x&0 \end{bmatrix})
 
Last edited:
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Oh, my friend helped me and figured out I need to sandwich the F inside the lambdas...and one of them has to be inverse...but which one should be inverse for me transforming a covariant tensor? Is it Lambda^-1 F Lambda or Lambda F Lambda^-1?

I think the only difference is that I rotate either by +theta or -theta...but supposing I want to rotate by +theta...?
 

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