Did photon obey Uncertainity Principle?

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Discussion Overview

The discussion revolves around the application of the Uncertainty Principle to photons, particularly addressing the implications of photons having no mass and how that affects the uncertainty relation. Participants explore the theoretical aspects of quantum mechanics as they relate to massless particles like photons.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant argues that since photons have no mass, applying the Uncertainty Principle leads to an implication that Planck's constant could be negative, which raises questions about the validity of the principle in this context.
  • Another participant points out that the uncertainty relation is derived from the commutation relation of momentum and position operators, emphasizing that photons carry momentum despite having no mass.
  • A different participant clarifies that the expression "velocity*mass" does not represent momentum accurately for massless particles and provides the correct dispersion relation for photons.
  • One participant mentions the single-slit diffraction phenomenon as an example of photons obeying the Uncertainty Principle.
  • Several participants express agreement that everything, including photons, obeys quantum principles, although one humorously refuses to comply with quantum principles.

Areas of Agreement / Disagreement

Participants exhibit a mix of agreement and disagreement. While there is a general acknowledgment that photons obey quantum principles, the application of the Uncertainty Principle to massless particles remains contested, with differing interpretations and clarifications being offered.

Contextual Notes

Some limitations in the discussion include the dependence on definitions of momentum and the implications of masslessness in quantum mechanics, which are not fully resolved.

sndtam
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Photon has no mass.So when we apply Uncertainity principle to photon
position*velocity*mass=greater than Plancks constant
So when we use mass as null,the equation implies that 0<h.
That is h is negative.But h is positive.
Please explain me this.
 
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The uncertainty relation follows from the commutation relation of the momentum and position operators. The photon does not carry a mass, but it does carry a momentum.
 
sndtam said:
velocity*mass
This is not momentum. This is an approximation of momentum at low velocity. The correct dispersion relations for the massless particles as the photon is
E=pc=\hbar\omega=\hbar c k
 
Last edited:
sndtam said:
Photon has no mass.So when we apply Uncertainity principle to photon
position*velocity*mass=greater than Plancks constant
So when we use mass as null,the equation implies that 0<h.
That is h is negative.But h is positive.
Please explain me this.

The single-slit diffraction phenomenon is the clearest example of photons "obeying" the HUP.

Zz.
 
Thank you
 
As far as we know, everything obeys quantum principles...including HUP...
 
Naty1 said:
As far as we know, everything obeys quantum principles...including HUP...


I refuse to obey your quantum principles ;)
 
Thanks a lot
 
maverick_starstrider said:
I refuse to obey your quantum principles ;)

A smart dope is in direct violation of my HUP.

- Werner
 

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