teste

\begin{equation} \label{eq:schroedinger} -\frac{\hbar^{2}}{2m} \nabla ^{2} \psi (\vec{r},t)+V(\vec{r},t) \psi (\vec{r},t) = i \hbar \frac{\partial}{\partial t} \psi (\vec{r},t) \end{equation} \alpha \equiv \alpha