Re: The temperature of a photon ?

In article <44fd41e7$0$75040$14726298@xxxxxxxxxxxxxxx>, "Peter Christensen" <PeCh@xxxxxxxxxxx> writes:
Does it make sence to talk about the temperature of a photon? (-My own
answer is no.)

A photon, no. Photons, yes.

It always applies that E = p*c (p is the momentum which depend only on the
wavelength) for a photon. But as the speed of light is always c, there can't
be a kinectic energy as for massive particles,

Oh, of course there can be kinetic energy. All of photon's energy is
kinetic.

where E_kin = 1/2 m*v^2 can
be expressed as a measure of temperature for a particle.

Not quite.

I know, that a radiation profile (photons) can express the temperature of
it's source, but I still don't think, that it will make sence to talk about
a temperature for single photons, as it would do when talking about massive
particles with E = E_kin = k_B*T.

It doesn't make sense to talk about temperature for single massive
particels, either. Temperature is an ensamble property.

Are there anybody who would like to try to define a temperature for a
photon?

Check out cavity radiation.

Mati Meron | "When you argue with a fool,
meron@xxxxxxxxxxxxxxxxx | chances are he is doing just the same"
.

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