# Proving the time-evolution of momentum operator

In QFT the evolution of momentum and field operators is given by $∂_0φ=i[H,φ]$ and $∂_0\pi=i[H,\pi]$.

Is it possible to derive these equations from the basic operator commutation relations or are they postulated?

Note: this is a follow-up to Canonical quantization of quantum field

• See the "Heisenberg picture". This is just the Schrodinger equation in a different point of view. – Ron Maimon May 3 '12 at 5:33