Slowing Down a Photon - Does It Make Sense?

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SUMMARY

A photon always travels at the speed of light, denoted as c, in any inertial frame. Discussions highlight that while the speed of light in a vacuum is constant at c, it can appear to slow down in various materials due to interactions with atoms, resulting in a longer travel time. The conversation also touches on the implications of Lorentz transformations for photons and the concept of group velocity in electromagnetic fields. Notably, experiments like Electromagnetically Induced Transparency (EIT) demonstrate scenarios where light can be effectively slowed down, but this does not alter the fundamental speed of individual photons.

PREREQUISITES
  • Understanding of Lorentz transformations in physics
  • Familiarity with the concept of group velocity in electromagnetic fields
  • Knowledge of Electromagnetically Induced Transparency (EIT) experiments
  • Basic principles of Maxwell's equations and their relation to the speed of light
NEXT STEPS
  • Research the implications of Lorentz transformations on massless particles
  • Study the phenomenon of Electromagnetically Induced Transparency (EIT) in detail
  • Explore the concept of group velocity versus phase velocity in wave mechanics
  • Investigate the effects of superfluidity on light propagation
USEFUL FOR

Physicists, students of quantum mechanics, and anyone interested in the behavior of light in various media and the fundamental principles of relativity.

karatemonkey
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Slowing down a photon

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Does a single unique photon ever not travel at c in the same inertial frame?
I'm stuck on the apparent problems with applying the Lorentz transformation to a photon. I don't think it makes sense physically to apply them to a photon. Talking about moving photons from rest to c, I don't think happens or even makes sense. When light is slowed down, isn't that really the group velocity of the EM field that gets slowed from which photons are emitted.
Anyway, enough rambling help!
 
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A photon always travels at c.
If you Lorentz transform, you will still get c.
 
Ok, so I got through the photons always have velocity c in any inertial frame part, which includes photons created inside a semi-conductor laser or in some EIT material,
I'm now stuck on how to reconcile photon velocity and the speed light slowing in EIT experiments. More specifically, is it proper to talk of the EM field taking up and giving back mass from the energy of the photons, and that the taking up and giving back by the field acts as a curvature of space-time? Is that even possible?
 
The speed of light* is only equal to c in vacuum. In other materials the speed of light can be less than c.

*Classical Maxwell-type speed of light, I don't know about for individual photons in a QM type analysis.
 
Last edited:
In a superfluid light can be slowed to a few miles per hour. As for if you mean in a vacuum yes in all frames of reference, except of course the photons own frame of reference it will be traveling at c.
 
I have heard physics profs say many a times that using Minkowski's space to understand such things is more profitable. It clears most of the so-called paradoxes.

Cheers
 
the speed of an individual photon is always c. when a photon travels through a material it can take a zig zag path to the other side as its affected by the atoms in the material so it will take longer to get to the other side and is effectively slowed down.
 

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