Expectation of partial time derivatives of $x$ in QM

Question

In Ehrenfest theorem we know that $$m\frac{d\left< x\right>}{dt}=\left< p\right>+m\left<\frac{\partial x}{\partial t}\right>.$$ So how can I exactly calculate a specific $\left<\frac{\partial x}{\partial t}\right>$ in coordinate representation?

Answer 1

The "partial time derivative symbol" $\frac{\partial }{\partial t}$ denotes the explicit time derivative. The fundamental phase space variables (such as, e.g. $\hat{x}$) don't depend explicitly on time, neither in the Heisenberg picture nor in Schrödinger picture.