$\underline{p} = ℏ \underline{k}$

p^{μ} = m \frac{d x^{μ}}{d τ} = γ m (\begin{matrix} c & v^{1} & v^{2} & v^{3} \end{matrix}) = (\begin{matrix} \frac{E}{c} & p^{i} \end{matrix})

p^{μ} p_{μ} = m^{2} c^{2}

Operator

\hat{p} = \frac{ℏ}{𝔦} \underline{\nabla}

Impuls