1st-order linear differential equation for the time evolution of an operator in the Heisenberg picture
![{\displaystyle \mathrm {i} \hbar {\frac {\mathrm {d} A(t)}{\mathrm {d} t}}=[A(t),H(t)]}](https://wikimedia.org/api/rest_v1/media/math/render/svg/4d58fecba17bf01fd549b9888a4a2f137d34e4da)