Vågpaketet
Vågpaketet, or the wave packet, is a localized disturbance formed by superposing waves with a spread of wavelengths. In quantum mechanics, the state of a particle is described by a wave function, and a localized particle state is often modeled as a vågpaket obtained by combining plane waves with amplitudes around a central wave number k0 (corresponding to momentum p0 = ħk0). The spread in wave numbers implies a spread in momentum, in line with the Heisenberg uncertainty principle, which explains why a localized packet cannot have perfectly definite position or momentum.
In a free particle setting, the different components of a vågpaket travel with different phase and group
The center of the vågpaket follows classical-like motion, with its position expectation value Δx advancing according