How to quantum mechanically describe the photon?

In summary, the discussion centered around the quantum description of photons and the momentum eigenfunctions. It was suggested to refer to textbooks such as "The Quantum Theory of Fields" by Weinberg and David Tong's lecture notes. There was also mention of the importance of helicity and the vector potential in the e/m field. Finally, a resource on the concept of photons was recommended.
  • #1
Somali_Physicist
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This might sound stupid , but I am wondering how exactly could I describe the momentum eigenfunctions of photons?

EDIT:
to destroy ambiguity, I am searching for a quantum mechanic description of monochromatic light similar to how we represent it classically as:

E-> = a->cos(wt+phi)
 
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  • #2
Somali_Physicist said:
This might sound stupid , but I am wondering how exactly could I describe the momentum eigenfunctions of photons?
##|p>## :biggrin:
 
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  • #3
Demystifier said:
##|p>## :biggrin:
more precisely, ##|p\rangle##
 
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  • #4
witty responses and as true as true can be. does it help our @Somali_Physicist ?
 
  • #5
A quantum description of photons requires quantizing the electromagnetic field. This is discussed in any textbook on quantum field theory or quantum optics, and in many quantum-mechanics textbooks. This will result in operators that create and destroy photons with definite momentum and polarization. Acting on the vacuum (the state of no particles) with a single-photon creation operator produces a momentum eigenfunction. Acting with the exponential of a creation operator (with a specific coefficient) will create a "coherent state" of photons, all with the same momentum, which is as close as you can get to a classical field in the quantum theory.
 
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  • #6
Avodyne said:
A quantum description of photons requires quantizing the electromagnetic field. This is discussed in any textbook on quantum field theory or quantum optics, and in many quantum-mechanics textbooks. This will result in operators that create and destroy photons with definite momentum and polarization. Acting on the vacuum (the state of no particles) with a single-photon creation operator produces a momentum eigenfunction. Acting with the exponential of a creation operator (with a specific coefficient) will create a "coherent state" of photons, all with the same momentum, which is as close as you can get to a classical field in the quantum theory.
Thank you
So there is no one liner equation ?

What is your textbook called
 
  • #8
Somali_Physicist said:
This might sound stupid , but I am wondering how exactly could I describe the momentum eigenfunctions of photons?
Weinberg's "The Quantum Theory of Fields" Chapter 2 has a nice discussion of momentum eigenstates of various particle types.

Demystifier said:
##|p>## :biggrin:
A. Neumaier said:
more precisely, ##|p\rangle##
There should also be helicity right? ##|p,\sigma\rangle##
 
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  • #9
DarMM said:
There should also be helicity right? ##|p,\sigma\rangle##
Or helicity left, ##|p, - \sigma\rangle ##
 
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  • #10
Somali_Physicist said:
So there is no one liner equation
The relevant equation is that for the vector potential of the e/m field in Lorentz gauge.
 
  • #11
A. Neumaier said:
Or helicity left, ##|p, - \sigma\rangle ##
What's the difference between the left and and right side of the brain? On the right side there is nothing right, while on the left side there is nothing left.
 
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  • #12
Demystifier said:
On the right side there is nothing right, while on the left side there is nothing left.

I prefer this: On the left side there is nothing right, while on the right side there is nothing left.
 
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  • #13
Pony said:
I prefer this: On the left side there is nothing right, while on the right side there is nothing left.
It's not sufficiently paradoxical. A quantum description is not good if it does not look like a paradox. :biggrin:
 
  • #14
It's not even right since on the right hand the thumb is at the left...
 

FAQ: How to quantum mechanically describe the photon?

What is a photon?

A photon is a fundamental particle of light and electromagnetic radiation. It has no mass, but carries energy and momentum.

How is the photon described in quantum mechanics?

In quantum mechanics, the photon is described as a quantized excitation of the electromagnetic field. It is treated as a wave-particle duality, meaning it exhibits properties of both a particle and a wave.

What is the relationship between energy and frequency of a photon?

The energy of a photon is directly proportional to its frequency, as described by the equation E = hf, where E is energy, h is Planck's constant, and f is frequency.

How does the quantum mechanical model explain the behavior of a photon?

The quantum mechanical model explains the behavior of a photon through the principles of superposition and uncertainty. This means that a photon can exist in multiple states simultaneously and its exact position and momentum cannot be determined at the same time.

Can a photon be described as a classical particle?

No, a photon cannot be described as a classical particle because it does not follow the laws of classical mechanics. It exhibits wave-like properties and its behavior is better explained through quantum mechanics.

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