Photon emission from dipole antenna

In summary, photons are emitted from the stationary protons in a dipole antenna, even though the protons themselves do not accelerate. This is because the electric field of the protons contributes to the electromagnetic wave. While protons are not the only charged entity inside the metal of the antenna, it is impossible for usual antennas to emit single-photon states. Instead, they emit coherent states, which behave more like classical electrical waves. These coherent states have a Poisson distribution for the number of photons, with both the average and standard deviation equal to the parameter lambda.
  • #1
Danyon
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Are photons emitted from the stationary protons in a dipole antenna? The protons don't accelerate at any point but their electric field does contribute to the electromagnetic wave.
 
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  • #2
Photons are the energy quanta of the (classical) EM wave and one of the known sources of EM wave is the antenna.
Danyon said:
The protons don't accelerate at any point but their electric field does contribute to the electromagnetic wave.
Are protons the only charged entity inside the metal making up the antenna?
 
  • #3
It's impossible to make usual antennas to emit single-photon (Fock) states. What you'll emit are coherent states, which are more like a classical electrical wave than single-photon Fock states. If dimmed down to intensities with average photon numbers close (or even less than) one, the coherent state consists to a large amount of the vacuum state. With some small probability you may register one or (to even lesser probability) more photons in a statistical way. The probability distribution for the photon number in such a coherent state is the Poisson distribution,
$$P(N)=\frac{\lambda^N}{N!} \exp(-\lambda),$$
where ##\lambda## is both the average number ##\langle N \rangle=\lambda## of registered photons as well as its standard devition ##\langle N^2 \rangle -\langle N \rangle^2=\lambda##.
 
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1. What is a dipole antenna?

A dipole antenna is a type of antenna that consists of two conductive elements, typically wires or rods, that are placed parallel to each other. It is a common type of antenna used in radio and telecommunications systems.

2. How does a dipole antenna emit photons?

A dipole antenna emits photons through the process of electromagnetic radiation. When an alternating current is applied to the antenna, it creates a changing electric field, which then creates a changing magnetic field. These changing fields interact with each other to produce electromagnetic waves, which are made up of photons.

3. What factors affect photon emission from a dipole antenna?

The main factors that affect photon emission from a dipole antenna are the frequency of the alternating current applied to the antenna, the length of the antenna, and the material and shape of the antenna. These factors can affect the strength and direction of the emitted photons.

4. Can the direction of photon emission from a dipole antenna be controlled?

Yes, the direction of photon emission from a dipole antenna can be controlled by adjusting the orientation and length of the antenna. For example, a dipole antenna that is perpendicular to the ground will emit photons in a different direction than one that is parallel to the ground.

5. What are some practical applications of dipole antennas and photon emission?

Dipole antennas and photon emission have many practical applications, including wireless communication systems, radar systems, and radio telescopes. They are also used in various scientific research and medical imaging technologies.

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