Until now we have discussed the evolution of a quantum system from the point of
view that the wavefunctions are evolving and the operators are fixed (Schrodinger basis). In this picture, the time evolution of an expectation value is
When the operator Q depends on time, this is modified to
Now, when the operator Q is time-independent, and the state basis vectors are transformed so that all of the time dependence is in the operators, putting us in the Heisenberg picture, 
, and 
, then the equation of motion is easily found to be (
commutes with H)
