Number of photons in an arbitrary EM field

In summary: EM field and then look at the excitation number for a given mode.In summary, the conversation discusses the calculation of the statistical distribution of the number of photons in different types of electromagnetic (EM) fields. It is mentioned that the easiest way to calculate this distribution for EM radiation is by dividing the power radiated by the energy per photon of the corresponding wavelength. However, for EM fields that include virtual photons, there is no definite answer as virtual particles cannot be counted. It is also noted that there is a photon number operator, but applying it to a wave function does not give a definite number of photons unless the wave function is a Fock state. The conversation also mentions the difficulties in calculating the number of photons
  • #36
I would suggest looking up some papers about testing of single photon detectors. This is frequently done using heavily attenuated lasers or other coherent sources and in some cases it is done in free space.
Nothing really unusual happens and this is mainly a "classical" calculation, you can estimate the mean number of photons/second by dividing by hf and when that number gets small enough your detector will measure a Poisson distribution; i.e.exactly what you would expect.
 
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Likes Dale and vanhees71
<h2>What is an EM field?</h2><p>An EM field, or electromagnetic field, is a physical field that is created by electrically charged particles. It consists of both electric and magnetic components and can vary in strength and direction.</p><h2>How are photons related to EM fields?</h2><p>Photons are the smallest units of light and they are the carriers of electromagnetic radiation. They are created and absorbed by charged particles in an EM field.</p><h2>What determines the number of photons in an EM field?</h2><p>The number of photons in an EM field is determined by the energy and frequency of the radiation. Higher energy and frequency correspond to a higher number of photons.</p><h2>Can the number of photons in an EM field be measured?</h2><p>Yes, the number of photons in an EM field can be measured using specialized equipment such as a photodetector. This device detects individual photons and can provide a measurement of the number present in the field.</p><h2>How does the number of photons in an EM field affect its properties?</h2><p>The number of photons in an EM field affects its intensity and energy. A higher number of photons results in a stronger and more energetic field, while a lower number results in a weaker and less energetic field.</p>

FAQ: Number of photons in an arbitrary EM field

What is an EM field?

An EM field, or electromagnetic field, is a physical field that is created by electrically charged particles. It consists of both electric and magnetic components and can vary in strength and direction.

How are photons related to EM fields?

Photons are the smallest units of light and they are the carriers of electromagnetic radiation. They are created and absorbed by charged particles in an EM field.

What determines the number of photons in an EM field?

The number of photons in an EM field is determined by the energy and frequency of the radiation. Higher energy and frequency correspond to a higher number of photons.

Can the number of photons in an EM field be measured?

Yes, the number of photons in an EM field can be measured using specialized equipment such as a photodetector. This device detects individual photons and can provide a measurement of the number present in the field.

How does the number of photons in an EM field affect its properties?

The number of photons in an EM field affects its intensity and energy. A higher number of photons results in a stronger and more energetic field, while a lower number results in a weaker and less energetic field.

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