How can photons interact if they travel at the speed of ligh

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Discussion Overview

The discussion revolves around the interaction of photons and the implications of massless particles traveling at the speed of light, particularly in the context of neutrino oscillations and Feynman diagrams. It explores theoretical concepts related to particle physics and the nature of interactions among particles.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant questions the interpretation of massless particles being "frozen in time" and how this relates to photons interacting and changing states.
  • Another participant argues that the statement about massless particles not being able to interact is a misinterpretation and points out the oversimplification of neutrino oscillations.
  • A further clarification is provided regarding mass eigenstates and their relative phases, suggesting that massless particles can still acquire different phases, which is essential for neutrino oscillations.
  • A participant seeks clarification on the meaning of "frozen in its state" as mentioned in the podcast.
  • One participant reiterates their initial question about the podcast that discussed the solar neutrino problem.

Areas of Agreement / Disagreement

Participants express differing interpretations of the implications of massless particles and their interactions, indicating that multiple competing views remain without a clear consensus.

Contextual Notes

The discussion includes assumptions about the nature of massless particles and their interactions, which may not be fully resolved. The implications of Feynman diagrams and the specifics of neutrino oscillations are also areas of complexity that are not definitively addressed.

freetheparticle
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I was listening to a podcast about the solar neutrino problem, and they discussed how we have deduced that neutrinos are not massless due to the fact that they interact with other particles (even if this interaction occurs rarely). I paraphrase: "a particle traveling at the speed of light is frozen in time and is frozen in its state. It can never change states." If that is the case, then how come we can see photons coming into and out of existence on Feynman diagrams? If they travel at the speed of light how is it possible for them to interact and change states?
 
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You are misinterpreting what they are saying. They are not saying a massless particle cannot interact. They are also hugely oversimplifying what neutrino oscillations are.
 
Orodruin said:
You are misinterpreting what they are saying. They are not saying a massless particle cannot interact. They are also hugely oversimplifying what neutrino oscillations are.
What do you think they mean by "frozen in its state"?
 
greswd said:
What do you think they mean by "frozen in its state"?

A more accurate (although still very over simplified) description would be that if all the mass eigenstates travel at the same velocity, which they would if they were massless, they cannot acquire a relative phase. It is the mass eigenstates acquiring different phases that is the basis of neutrino oscillations.
 
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freetheparticle said:
I was listening to a podcast about the solar neutrino problem, and they discussed how we have deduced that neutrinos are not massless due to the fact that they interact with other particles (even if this interaction occurs rarely). I paraphrase: "a particle traveling at the speed of light is frozen in time and is frozen in its state. It can never change states." If that is the case, then how come we can see photons coming into and out of existence on Feynman diagrams? If they travel at the speed of light how is it possible for them to interact and change states?

which podcast is this?
 

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