31. When the dispersion is anomalous, however, group velocity is no longer an indicator of signal velocity. 32. Wave packets have group velocity and phase velocity. 33. :The dot itself moves faster than C, as a result of the group velocity of the photons. 34. The result of group velocity dispersion, whether negative or positive, is ultimately temporal spreading of the pulse. 35. The red dot moves with the phase velocity, and the green dots propagate with the group velocity . 36. The angular intervals for the DSW phase and group velocities ( ??ph and ??gr ) are different. 37. When reading about the group velocity , I always find the discussion framed in terms of wave packets. 38. In deep water the groups travel at a group velocity which is half of the phase speed. 39. The group velocity is defined as: 40. Usually, such reports deal with a phase velocity or group velocity faster than the vacuum velocity of light.
