Time Evolution of a Quantum Wave Packet

Shown is a free Gaussian-shaped quantum mechanical wave packet.  This is a minimum-uncertainty wave packet (ΔxΔp = h/4π) at t = 0.  Restart.  The top panel shows phase as color and the bottom panel shows the real and imaginary parts of the wave function. 

For visualization purposes: 2m = h/2π = 1.

Note that the wave function spreads with time: the high-momentum components lead the center of the packet while the low-momentum components lag the center of the packet.  This spreading is more/less pronounced if the packet is narrow/broad in position space as such a packet requires more/less of a spread in momentum.