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phase velocity and Why doesn't anomalous dispersion allow faster-than-light propagation?

PhaseIt seems that the phase velocity of light could be greater than c$c$, if $\sqrt{\epsilon \mu} < 1/c$, i.e. for anomalous dispersion.  

  1. What areAre there examples of such media? For diamagnetics it seems possible since $\mu < \mu_0$.

  2. WhatAnd what is the physical meaning of phase velocity in this case, besides being speed of wave surface? Why it cannot be seen as a physical entity that is traveling faster than light?

phase velocity and anomalous dispersion

Phase velocity of light could be greater than c, if $\sqrt{\epsilon \mu} < 1/c$, i.e. for anomalous dispersion.  

  1. What are examples of such media? For diamagnetics it seems possible since $\mu < \mu_0$.

  2. What is the physical meaning of phase velocity, besides being speed of wave surface? Why it cannot be seen as a physical entity faster than light?

Why doesn't anomalous dispersion allow faster-than-light propagation?

It seems that the phase velocity of light could be greater than $c$, if $\sqrt{\epsilon \mu} < 1/c$, i.e. for anomalous dispersion.

  1. Are there examples of such media? For diamagnetics it seems possible since $\mu < \mu_0$.

  2. And what is the physical meaning of phase velocity in this case, besides being speed of wave surface? Why it cannot be seen as a physical entity that is traveling faster than light?

2 added 5 characters in body
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Phase velocity of light could be greater than c, if $\sqrt{\epsilon \mu} < 1/c$, i.e. for anomalous dispersion.

  1. What are examples of such media? For diamagnetics it seems possible since $\mu < \mu_0$.

  2. What is the physical meaning of phase velocity, besides being speed of wave surface? Why it cannot be seen as a physical enityentity faster than light?

Phase velocity of light could be greater than c, if $\sqrt{\epsilon \mu} < 1/c$, i.e. for anomalous dispersion.

  1. What are examples of such media? For diamagnetics it seems possible since $\mu < \mu_0$.

  2. What is physical meaning of phase velocity, besides being speed of wave surface? Why it cannot be seen as a physical enity faster than light?

Phase velocity of light could be greater than c, if $\sqrt{\epsilon \mu} < 1/c$, i.e. for anomalous dispersion.

  1. What are examples of such media? For diamagnetics it seems possible since $\mu < \mu_0$.

  2. What is the physical meaning of phase velocity, besides being speed of wave surface? Why it cannot be seen as a physical entity faster than light?

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source | link

phase velocity and anomalous dispersion

Phase velocity of light could be greater than c, if $\sqrt{\epsilon \mu} < 1/c$, i.e. for anomalous dispersion.

  1. What are examples of such media? For diamagnetics it seems possible since $\mu < \mu_0$.

  2. What is physical meaning of phase velocity, besides being speed of wave surface? Why it cannot be seen as a physical enity faster than light?