Formula_25293

\[\begin{gathered}\psi(x)=\frac{1}{(2 \pi)^{3 / 2}} \int \frac{1}{\sqrt{2 p_{0}}}\left[a_{\lambda}(p) e^{-i p x} u_{\lambda}(p)+\right. \\\left.+\tilde{a}_{\lambda}^{+}(p) e^{i p x} u_{\lambda}(-p)\right] d p .\end{gathered}\]