11. Does stopping the group velocity means that the individual light waves themselves were stopped? 12. What travels at the group velocity for a monochromatic wave? 13. The group velocity therefore depends upon the dispersion relation connecting ? and " k ". 14. Showing that the velocity of a localized particle in quantum mechanics is its group velocity . 15. The deep-water group velocity is half the phase velocity. 16. Modal dispersion during propagation in the waveguide then provides group velocity dispersion to the signal. 17. This shows a wave with the group velocity and phase velocity going in different directions. 18. In dispersive media the phase velocity is not necessarily the same as the group velocity . 19. For example, the group velocity may have any value from zero up to Swihart velocity. 20. By definition, the group velocity \ boldsymbol { v } _ g is given by:
