Update 2022-03-15 10:07
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<!DOCTYPE html>
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<html lang="en">
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<head>
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<!-- 2022-03-07 Mon 20:38 -->
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<!-- 2022-03-15 Tue 08:10 -->
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<meta charset="utf-8">
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<meta name="viewport" content="width=device-width, initial-scale=1">
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<title>Pre-Quantum Electrodynamics</title>
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@@ -1310,10 +1310,6 @@ Table of contents
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</summary>
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<ul>
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<li>
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<a href="./d_m.html#d_m">Diagnostics: Mathematical Preliminaries</a><span class="headline-id">d.m</span>
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</li>
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<li>
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<a href="./d_ems.html#d_ems">Diagnostics: Electromagnetostatics</a><span class="headline-id">d.ems</span>
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</li>
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@@ -1352,6 +1348,10 @@ Table of contents
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<li>
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<a href="./d_red.html#d_red">Diagnostics: Relativistic Electrodynamics</a><span class="headline-id">d.red</span>
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</li>
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<li>
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<a href="./d_m.html#d_m">Diagnostics: Compendium - Mathematics</a><span class="headline-id">d.m</span>
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</li>
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</ul>
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@@ -1616,7 +1616,7 @@ Table of contents
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<p>
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We have seen that a four-vector transforms according to
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\[
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\bar{a}^\mu = \Lambda_\nu^\mu a^\nu
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\bar{a}^\mu = \Lambda^\mu{}_\nu a^\nu
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\]
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in which \(\Lambda\) is a matrix representing the Lorentz transformation.
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The form this matrix takes depends on the actual transformation: for the specific
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@@ -1628,11 +1628,11 @@ case of motion in the \(x\) direction with velocity \(v\),
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0 & 0 & 1 & 0 \\
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0 & 0 & 0 & 1 \end{array} \right).
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\]
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A four-vector is synonymous to a {\bf rank-one tensor}.
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A four-vector is synonymous to a <b>rank-one tensor</b>.
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Higher-rank tensors are simply objects carrying more indices.
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For example, a {\bf rank-two tensor} transforms as
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For example, a <b>rank-two tensor</b> transforms as
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\[
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\bar{t}^{\mu \nu} = \Lambda^\mu_\lambda \Lambda^\nu_\sigma t^{\lambda \sigma}.
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\bar{t}^{\mu \nu} = \Lambda^\mu{}_\lambda \Lambda^\nu{}_\sigma t^{\lambda \sigma}.
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\]
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Such a rank-two tensor can be represented similarly to a matrix:
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\[
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@@ -1656,59 +1656,89 @@ Under the Lorentz transformation along \(x\) defined above, we can work out
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how the nonvanishing elements of an antisymmetric tensor transform:
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</p>
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\begin{align}
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\bar{t}_a^{01} &= \Lambda^0_\mu \Lambda^1_\nu t_a^{\mu \nu}
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= \Lambda^0_0 \Lambda^1_0 t_a^{00} + \Lambda^0_1 \Lambda^1_0 t_a^{10}
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+ \Lambda^0_0 \Lambda^1_1 t_a^{01} + \Lambda^0_1 \Lambda^1_1 t_a^{11} \\
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& = (\Lambda^0_0 \Lambda^1_1 - \Lambda^0_1 \Lambda^1_0) t_a^{01}
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\bar{t}_a^{01} &= \Lambda^0{}_\mu \Lambda^1{}_\nu t_a^{\mu \nu}
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= \Lambda^0{}_0 \Lambda^1{}_0 t_a^{00} + \Lambda^0{}_1 \Lambda^1{}_0 t_a^{10}
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+ \Lambda^0{}_0 \Lambda^1{}_1 t_a^{01} + \Lambda^0{}_1 \Lambda^1{}_1 t_a^{11} \\
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& = (\Lambda^0{}_0 \Lambda^1{}_1 - \Lambda^0{}_1 \Lambda^1{}_0) t_a^{01}
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= \gamma^2 (1 - \beta^2) t_a^{01} = t_a^{01}, \\
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\bar{t}_a^{02} &= \Lambda^0_\mu \Lambda^2_\nu t_a^{\mu \nu}
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= \Lambda^0_0 \Lambda^2_2 t_a^{02} + \Lambda^0_1 \Lambda^2_2 t_a^{12}
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\bar{t}_a^{02} &= \Lambda^0{}_\mu \Lambda^2{}_\nu t_a^{\mu \nu}
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= \Lambda^0{}_0 \Lambda^2{}_2 t_a^{02} + \Lambda^0{}_1 \Lambda^2{}_2 t_a^{12}
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= \gamma (t_a^{02} - \beta t_a^{12}), \\
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\bar{t}_a^{03} &= \Lambda^0_\mu \Lambda^3_\nu t_a^{\mu \nu}
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= \Lambda^0_0 \Lambda^3_3 t_a^{03} + \Lambda^0_1 \Lambda^3_3 t_a^{13}
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\bar{t}_a^{03} &= \Lambda^0{}_\mu \Lambda^3{}_\nu t_a^{\mu \nu}
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= \Lambda^0{}_0 \Lambda^3{}_3 t_a^{03} + \Lambda^0{}_1 \Lambda^3{}_3 t_a^{13}
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= \gamma (t_a^{03} - \beta t_a^{13}), \\
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\bar{t}_a^{12} &= \Lambda^1_\mu \Lambda^2_\nu t_a^{\mu \nu}
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= \Lambda^1_0 \Lambda^2_2 t_a^{02} + \Lambda^1_1 \Lambda^2_2 t_a^{12}
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\bar{t}_a^{12} &= \Lambda^1{}_\mu \Lambda^2{}_\nu t_a^{\mu \nu}
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= \Lambda^1{}_0 \Lambda^2{}_2 t_a^{02} + \Lambda^1{}_1 \Lambda^2{}_2 t_a^{12}
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= \gamma (t_a^{12} - \beta t_a^{02}), \\
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\bar{t}_a^{13} &= \Lambda^1_\mu \Lambda^3_\nu t_a^{\mu \nu}
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= \Lambda^1_0 \Lambda^3_3 t_a^{03} + \Lambda^1_1 \Lambda^3_3 t_a^{13}
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\bar{t}_a^{13} &= \Lambda^1{}_\mu \Lambda^3{}_\nu t_a^{\mu \nu}
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= \Lambda^1{}_0 \Lambda^3{}_3 t_a^{03} + \Lambda^1{}_1 \Lambda^3{}_3 t_a^{13}
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= \gamma (t_a^{13} - \beta t_a^{03}), \\
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\bar{t}_a^{23} &= \Lambda^2_\mu \Lambda^3_\nu t_a^{\mu \nu}
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= \Lambda^2_2 \Lambda^3_3 t_a^{23}
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\bar{t}_a^{23} &= \Lambda^2{}_\mu \Lambda^3{}_\nu t_a^{\mu \nu}
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= \Lambda^2{}_2 \Lambda^3{}_3 t_a^{23}
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= t_a^{23}.
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\end{align}
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<p>
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Comparing with the transformation rules for the electromagnetic field which we obtained in (\ref{eq:EMFieldsLorentzTransfo}), we can define the
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Comparing with the transformation rules for the electromagnetic field which we obtained in <a href="./red_rem_Ltf.html#EMtr">EMtr</a>, we can define the
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</p>
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<div class="core div" id="orge72c66d">
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<div class="core div" id="org5361587">
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<p>
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<b>Electromagnetic Field Tensor</b>
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</p>
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<div class="eqlabel" id="orgdddfe8b">
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<p>
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<a id="Fmunu"></a><a href="./red_rem_Fmunu.html#Fmunu"><svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="currentColor" class="bi bi-link" viewBox="0 0 16 16">
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<path d="M6.354 5.5H4a3 3 0 0 0 0 6h3a3 3 0 0 0 2.83-4H9c-.086 0-.17.01-.25.031A2 2 0 0 1 7 10.5H4a2 2 0 1 1 0-4h1.535c.218-.376.495-.714.82-1z"/>
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<path d="M9 5.5a3 3 0 0 0-2.83 4h1.098A2 2 0 0 1 9 6.5h3a2 2 0 1 1 0 4h-1.535a4.02 4.02 0 0 1-.82 1H12a3 3 0 1 0 0-6H9z"/>
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</svg></a>
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</p>
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<div class="alteqlabels" id="org9e15d6e">
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</div>
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</div>
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<p>
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{\bf Electromagnetic Field Tensor}
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\[
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F^{\mu \nu} = \left( \begin{array}{cccc}
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0 & E_x/c & E_y/c & E_z/c \\
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-E_x/c & 0 & B_z & -B_y \\
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-E_y/c & -B_z & 0 & B_x \\
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-E_z/c & B_y & -B_x & 0 \end{array} \right)
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\]
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F^{\mu \nu} = \left( \begin{array}{cccc}
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0 & E_x/c & E_y/c & E_z/c \\
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-E_x/c & 0 & B_z & -B_y \\
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-E_y/c & -B_z & 0 & B_x \\
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-E_z/c & B_y & -B_x & 0 \end{array} \right)
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\tag{Fmunu}\label{Fmunu}
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\]
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</p>
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</div>
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<p>
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together with the handy
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</p>
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<div class="main div" id="org5c6516a">
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<div class="main div" id="org53973f7">
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<p>
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<b>Dual Field Tensor</b>
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</p>
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<div class="eqlabel" id="orgae9a2b2">
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<p>
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<a id="Gmunu"></a><a href="./red_rem_Fmunu.html#Gmunu"><svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="currentColor" class="bi bi-link" viewBox="0 0 16 16">
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<path d="M6.354 5.5H4a3 3 0 0 0 0 6h3a3 3 0 0 0 2.83-4H9c-.086 0-.17.01-.25.031A2 2 0 0 1 7 10.5H4a2 2 0 1 1 0-4h1.535c.218-.376.495-.714.82-1z"/>
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<path d="M9 5.5a3 3 0 0 0-2.83 4h1.098A2 2 0 0 1 9 6.5h3a2 2 0 1 1 0 4h-1.535a4.02 4.02 0 0 1-.82 1H12a3 3 0 1 0 0-6H9z"/>
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</svg></a>
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</p>
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<div class="alteqlabels" id="org9c07047">
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</div>
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</div>
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<p>
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{\bf Dual Field Tensor}
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\[
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G^{\mu \nu} = \left( \begin{array}{cccc}
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0 & B_x & B_y & B_z \\
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-B_x & 0 & -E_z/c & E_y/c \\
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-B_y & E_z/c & 0 & -E_x/c \\
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-B_z & -E_y/c & E_x/c & 0 \end{array} \right)
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\]
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G^{\mu \nu} = \left( \begin{array}{cccc}
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0 & B_x & B_y & B_z \\
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-B_x & 0 & -E_z/c & E_y/c \\
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-B_y & E_z/c & 0 & -E_x/c \\
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-B_z & -E_y/c & E_x/c & 0 \end{array} \right)
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\tag{Gmunu}\label{Gmunu}
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\]
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</p>
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</div>
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@@ -1723,12 +1753,27 @@ obtained from the field tensor by the substitution
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<p>
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Our electromagnetic field transformation laws then become the simple
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</p>
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<div class="core div" id="org7f5ef81">
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<div class="core div" id="org840afc2">
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<p>
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<b>Lorentz Transformation Rules for EM Fields</b>
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</p>
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<div class="eqlabel" id="orga8672c3">
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<p>
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<a id="LorF"></a><a href="./red_rem_Fmunu.html#LorF"><svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="currentColor" class="bi bi-link" viewBox="0 0 16 16">
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<path d="M6.354 5.5H4a3 3 0 0 0 0 6h3a3 3 0 0 0 2.83-4H9c-.086 0-.17.01-.25.031A2 2 0 0 1 7 10.5H4a2 2 0 1 1 0-4h1.535c.218-.376.495-.714.82-1z"/>
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<path d="M9 5.5a3 3 0 0 0-2.83 4h1.098A2 2 0 0 1 9 6.5h3a2 2 0 1 1 0 4h-1.535a4.02 4.02 0 0 1-.82 1H12a3 3 0 1 0 0-6H9z"/>
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</svg></a>
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</p>
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<div class="alteqlabels" id="org49ca23d">
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</div>
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</div>
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<p>
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{\bf Lorentz Transformation Rules for EM Fields}
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\[
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\bar{F}^{\mu \nu} = \Lambda^\mu_\lambda \Lambda^\nu_\sigma F^{\lambda \sigma}
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\]
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\bar{F}^{\mu \nu} = \Lambda^\mu{}_\lambda \Lambda^\nu{}_\sigma F^{\lambda \sigma}
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\tag{LorF}\label{LorF}
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\]
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</p>
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</div>
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@@ -1753,7 +1798,7 @@ target="_blank">Creative Commons Attribution 4.0 International License</a>.
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</div>
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<div id="postamble" class="status">
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<p class="author">Author: Jean-Sébastien Caux</p>
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<p class="date">Created: 2022-03-07 Mon 20:38</p>
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<p class="date">Created: 2022-03-15 Tue 08:10</p>
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<p class="validation"></p>
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</div>
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