Four Vector

Topics

• Covariant Vector
• Contravariant Vector

$x_{\mu }=(ct,\vec{r})$

• $c$ is the speed of light
• $\vec{r}$ is the position vector

$p_{\mu }=\left(\frac{E}{c},\vec{p}\right)$

$k_{\mu }=\left(\omega /c,\vec{k}\right)$

• $\vec{k}$ is the linear Wavenumber

$A_{\mu }=(V/c,\vec{A})$

$J_{\mu }=(\rho c,\vec{J})$

• $\rho$ is the charge density