Linked from

The 20 pages that link to Group velocity, each with the reason it gives.

• Refractive indexCompared with: It can differ from phase velocity, so it yields a different index-like measure.

• Speed of lightCompared with: In dispersive media it can differ from both phase speed and information speed.

• Standing waveCompared with: A standing pattern has no traveling envelope carrying it along.

• Phase velocityCompared with: It describes packet motion, which can differ from the motion of constant phase.

• Phase (waves)Compared with: It tracks the envelope, unlike phase velocity, which tracks constant phase.

• Sound speedCompared with: It can differ from phase velocity when sound is dispersive.

• SpeedRelated: It can differ from phase velocity, distinguishing the motion of a wave pattern from its envelope.

• WavefrontCompared with: It can differ from phase propagation, which wavefronts track.

• Dispersion relationRelated: Its value follows from the slope of frequency against wave number.

• DispersionRelated: Its frequency dependence determines how quickly a pulse envelope travels through a dispersive medium.

• Effective massRelated: In a band, the slope of energy with momentum sets carrier group velocity.

• Matter waveRelated: For a free particle, the matter-wave packet's group velocity corresponds to particle velocity.

• Seismic velocityCompared with: It can differ from phase velocity in dispersive seismic waves.

• Coherence lengthRelated: It converts coherence time into propagation distance for a wave packet.

• WaveguideRelated: A guide's dispersion makes energy travel at a frequency-dependent speed.

• Photon momentumRelated: In dispersive media, momentum cannot generally be inferred by substituting group speed for vacuum light speed.

• Wave vectorCompared with: It describes packet motion; the wave vector describes spatial phase variation.

• Free particleRelated: For a nonrelativistic free particle, a wave packet's group velocity matches its momentum divided by mass.

• Wave packetRelated: It often describes the packet’s motion when its envelope remains identifiable.

• Scharnhorst effectCompared with: A change in phase velocity does not by itself show that information travels faster.