Wave Packets, Phase and Group Velocity

The microscopic world is telling us that we should think of radiation and electrons as both a particle and a wave, so we develop a mathematical description which has both particle properties and wave properties through a concept called ‘wave packet’

Wave Packet #

• It is localized and moves together as an entity: particle property
• Within the wave packet there a few oscillations: wave property

https://www.desmos.com/calculator/krncl8bvsd

Phase velocity: the velocity of the wave that has the higher wavenumber Group velocity: the velocity of the wave packet, the wave that has the lower wavenumber.

https://www.desmos.com/calculator/qoovuqyfnd