Consider a wavepacket Ψ Ψ ( x , t ) ∝ ∝ exp ⁡ ⁡ [ − − x 2 / ( 2 σ σ ) 2 + i k 0 x ] with initial momentum ℏ ℏ k 0 which evolves in the general Hamiltonian of a Gaussian, uncorrelated, disordered medium: