[QUE/QFT-04010] QFT-PROBLEM

Use the expansion of Schrodinger field \(\psi(x,t)\) in terms of plane waves \[\psi(\mathbf x,t) =\frac{1}{(2\pi)^{3/2}} \int d\mathbf k \exp(i\mathbf k.\mathbf x) a(\mathbf k,t)\] and the canonical commutation relations to prove that \[ [a(\mathbf k), a^\dagger(\mathbf k{'})] = \delta(\mathbf k-\mathbf k{'}).\]