Dispersion relation and Photonic Energy and Momentum Equations in QM

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SUMMARY

The discussion focuses on the relationship between energy, momentum, and dispersion relations in quantum mechanics, specifically for photons. The equations E = h x f and p = h / lambda are established as valid, with the dispersion relation in vacuum given by c = lambda x f. The conversation explores how these relationships adapt when dispersion relations change and questions the validity of expressing momentum as p = h x f / c, clarifying that c should represent the wave velocity in the medium rather than the vacuum speed of light.

PREREQUISITES
  • Understanding of quantum mechanics principles
  • Familiarity with the equations of photon energy and momentum
  • Knowledge of dispersion relations in different media
  • Basic grasp of wave-particle duality
NEXT STEPS
  • Research the implications of varying dispersion relations on photon behavior
  • Study the concept of wave velocity in different media and its effects on momentum
  • Explore advanced quantum mechanics topics related to energy-momentum relationships
  • Learn about the applications of E = h c / lambda in various physical contexts
USEFUL FOR

Physicists, quantum mechanics students, and researchers interested in the properties of photons and their interactions in different media.

DaTario
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Hi All,

In quantum mechanics, related to photon, we have these two equations as valid ones:

E = h x f

p = h / lambda

But we have in vacuum the dispersion relation c = lambda x f.

1) How these relations change when the dispersion relation change ?

2) Is it universally correct to write p = h x f / c ?


Thanks ALL

Best Regards

DaTario
 
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Or still, is it correct to write:

E = h c / lambda ?

Best wishes

DaTario
 
Yes, but at least c should be understood to mean not the vacuum velocity but the velocity of the wave in the medium.
 

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