Occupation Numbers Of Phonons/Photons

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SUMMARY

The discussion centers on the concept of occupation numbers for phonons and photons, referencing Mahan's assertion that they do not possess occupation numbers. It is established that while certain states, such as coherent states, are not eigenvectors of the occupation number operator, Fock states do have a definite number of photons. The key conclusion is that Mahan's statement is misleading; the states discussed are superpositions of different photon number states, indicating that occupation numbers can exist in specific contexts.

PREREQUISITES
  • Understanding of quantum mechanics principles
  • Familiarity with Fock states and coherent states
  • Knowledge of Hermitian operators in quantum theory
  • Basic grasp of superposition in quantum states
NEXT STEPS
  • Research the properties of Fock states in quantum optics
  • Explore the mathematical formulation of coherent states
  • Study the implications of Hermitian operators in quantum mechanics
  • Investigate superposition principles in quantum state theory
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Quantum physicists, students of quantum mechanics, and researchers in quantum optics will benefit from this discussion, particularly those interested in the behavior of phonons and photons in various quantum states.

pirate phy
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According to Mahan, phonons or photons doesn't have occupation number. Is this true?http://i.tinyuploads.com/MBwW0j.jpg
 
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there are states with definite photons number (Fock states)
and there are states (e.g coherent states) which are not eigenvectors of the " occupation number" hermitian operator.
 
pirate phy said:
According to Mahan, phonons or photons doesn't have occupation number. Is this true?http://i.tinyuploads.com/MBwW0j.jpg

The text is not saying that. It says that the particular states mentioned (excitations) are
superpositions of states with a different but definite number of photons.
 

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