Is the polarization of light relative?

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Discussion Overview

The discussion revolves around the question of whether the measured polarization of a beam of light is relative to the observer's frame of reference. Participants explore the implications of this idea through analogies and comparisons with massive and massless particles, focusing on the nature of polarization in different frames.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant speculates that the polarization of light may be relative to the observer's frame, drawing an analogy with the path of a bullet, which appears curved in a rotating frame.
  • Another participant introduces the concept of a massive spinning particle, noting that different observers may perceive its spin differently based on their relative motion.
  • The same participant contrasts this with massless particles, stating that they cannot be overtaken and thus have a consistent polarization that is not dependent on the observer's frame.
  • There is a clarification regarding the distinction between massive and massless particles, with some participants correcting each other on terminology and understanding of constraints related to polarization.

Areas of Agreement / Disagreement

Participants express differing views on the relativity of polarization, with some supporting the idea that it may depend on the observer's frame, while others focus on the implications of mass and the nature of light. The discussion remains unresolved, with no consensus reached.

Contextual Notes

Participants highlight the complexities of distinguishing between mathematical representations and physical realities, indicating that assumptions about the nature of polarization and reference frames may not be fully addressed.

Nirgal
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I was wondering if anyone had input into this question. Is the measured polarization of a beam of light relative to the frame of the observer?

In the texts on Optics that I've read, there does not seem to be any reference to the observer's frame. It is only mentioned that light is Left-circularly polarized or linearly polarized, etc.

When we describe polarization we ascribe to the light-beam in question a vector representing the polarized state. But is that polarized state the same for each observer?

I am speculating that the polarization is relative and this is my (naive) reasoning.
If we were discussing the path of a bullet, then in the frame of reference of somebody rotating, the path of the bullet would be curved. So the time dependent vector representing the path of the bullet would depend on the frame of reference of the observer.

Now, the physics of light is so bizarre and I can barely understand it that I do not assume that the analogy between bullets and light can be taken very far. The point of the analogy though is that polarization state is described by a vector and similarly the path of the bullet. And since the mathematical abstraction that the vector represents depends on the reference frame for the bullet then I would assume that the polarization similarly depends on the reference frame of the observer as well.

This is one of my problems in physics though. I am constantly in a wrestling match between distinguishing the mathematics from the physics.
 
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First consider the case of a massive spinning particle. Say that one observer says the particle is spinning like a right-handed screw going into a piece of wood, i.e., clockwise as seen from behind. Another observer who is traveling in the same direction as the particle, but faster, sees the particle as going backward, and therefore says it is spinning like a left-handed screw.

It's different in the case of a massless particle. You can't overtake a massless particle, because massless particles travel at c.

This is also why it's possible to have a law of physics that says that light is always transversely polarized. You can't have a constraint on the polarization of a massive particle, because there would be no way to define the constraint in the frame where the particle was at rest.
 
bcrowell said:
First consider the case of a massive spinning particle. Say that one observer says the particle is spinning like a right-handed screw going into a piece of wood, i.e., clockwise as seen from behind. Another observer who is traveling in the same direction as the particle, but faster, sees the particle as going backward, and therefore says it is spinning like a left-handed screw.

It's different in the case of a massless particle. You can't overtake a massless particle, because massless particles travel at c.

This is also why it's possible to have a law of physics that says that light is always transversely polarized. You can't have a constraint on the polarization of a massive particle, because there would be no way to define the constraint in the frame where the particle was at rest.
I suppose you mean massless.
 
Passionflower said:
I suppose you mean massless.

No, I meant massive.
 
bcrowell said:
No, I meant massive.
Oh I see, you are talking about a constraint, took me a second the realize what you wrote.

Sorry for that.
 

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