Work Out Number of Photons in Vacuum

[Bruce Haawkins]

given a complete vacume.(Excluding the photons)
given a volume.
given a temprature.
given a wavelenth.
work out the number of photons in the vacume?

 

[Mentz114]

given a complete vacume.
given a volume.
given a temprature.
given a wavelenth.
work out the number of photons in the vacume?

Zero.

The vacuum is empty by definition. There must be an electromagnetic field in order for photons to exist and that is not a complete vacuum.
You have been mislead if you think otherwise.

 

[Bruce Haawkins]

Zero.

The vacuum is empty by definition. There must be an electromagnetic field in order for photons to exist and that is not a complete vacuum.
You have been mislead if you think otherwise.

I meant with the photons in. I am looking for an equation to work this out can you mabe help me please. If the photons are not enuph then just a small amount of gass to get an electro- magnetic field.

 

[Mentz114]

For coherent states if the average photon occupancy number ( for a mode $k$) is $\bar{N}$ then the probability of detecting $n$ photons with mode $k$ is given by the Poisson distribution with mean $\bar{N}$.

 

[stevendaryl]

Zero.

The vacuum is empty by definition. There must be an electromagnetic field in order for photons to exist and that is not a complete vacuum.
You have been mislead if you think otherwise.

Well, I think that the question can be interpreted in terms of black-body radiation. Imagine a closed impenetrable box of some sort where the walls are kept at a constant temperature $T$. The box is evacuated of air. The question is whether the space inside will fill with low-frequency photons. Or classically, will there be a nonzero energy density for electromagnetic energy inside the box?

 

[Bruce Haawkins]

For coherent states if the average photon occupancy number ( for a mode $k$) is $\bar{N}$ then the probability of detecting $n$ photons with mode $k$ is given by the Poisson distribution with mean $\bar{N}$.

So if I have 1cubic cm volume of space with 2 gass particles with full valency levels at close to 0 degrees kelven and I have next to it some other substance at 273 kelven will there be a photon transfer to the space?

 

[Bruce Haawkins]

Well, I think that the question can be interpreted in terms of black-body radiation. Imagine a closed impenetrable box of some sort where the walls are kept at a constant temperature $T$. The box is evacuated of air. The question is whether the space inside will fill with low-frequency photons. Or classically, will there be a nonzero energy density for electromagnetic energy inside the box?

Hi There stevendaryl If I have the temprature inside the box and I have the wavelenth of the low-frequency photons is there any chance that you can give me an equation to work out the energy in the box

 

[jtbell]

Perhaps this might be useful:

https://en.wikipedia.org/wiki/Photon_gas

 

[Bruce Haawkins]

Perhaps this might be useful:

https://en.wikipedia.org/wiki/Photon_gas

Thanks