fredag 22 februari 2013

IR Photons as Phlogistons

A photon is as elementary particle the carrier of the electromagnetic force. 

A phonon is as collective elastic excitation in a lattice of atom or molecules the carrier of sound, referred to as a "quasiparticle". 

A phonon is a collective sound wave while a photon is a "light particle". In a previous post I considered  an acoustic model of radiative heat transfer between the Earth surface and the atmosphere and outer space, in the form of a string instrument with energy transfer from string to soundboard to surrounding air.

It is common to describe infrared radiative heat transfer between two bodies as a two-way flow of IR photon particles carrying "energy quanta" back and forth between the bodies. I have argued that this view is non-physical in the sense that energy is supposed to be carried not only from warm to cold, but also from cold to warm which is in violation of the 2nd law of thermodynamics. 

To understand that the particle view is non-physical, it is illuminating to consider a model of the string instrument where the concept of phonon wave is replaced by "phonon particle" as an acoustic counterpart to a photon particle. A "phonon particle" would thus be a form of elementary particle as "sound particle" and "carrier of sound (force)".  

We would then view the sound produced by the string instrument as consisting of a two-way flow of phonons between string and soundboard and between soundboard and surrounding air. In this model the sound of the surrounding air would send phonons to the soundboard which would send phonons to the string. This would be in violation with our experience reflecting the 2nd law, that it is the string which makes the soundboard vibrate, which makes the sound wave in the air. 

We understand that a phonon particle model of a string instrument is non-physical as violation of the 2nd law and thus misleading.

In the same way an IR photon particle model of infrared radiative heat transfer is non-physical as violation of the 2nd law and thus misleading. Yet this model underlies the idea of "backradiation" from the cold atmosphere the to warmer Earth surface, which is a central part of CO2 alarmism.
Such a photon theory postulating heat transfer by photon particles without mass, charge, color, odor or taste, can be compared with the phlogiston theory postulating that in all flammable materials there is present phlogiston, a substance without color, odor, taste, or weight that is given off in burning.

Notice that because of the long wave length of infrared radiation, and IR-photon is similar to a phonon and thus is better described as collective wave phenomenon than as discrete particle. Compare with previous post on the subject.

PS There is a connection between optical phonons as large amplitude out-of-phase wave vibration of a lattice of two different atoms with different mass (as compared to acoustic small amplitude in-phase vibration), and the analysis of blackbody radiation on Computational Blackbody Radiation with incoming and outgoing radiation out-of-phase (also characteristic of a string instrument designed to give large amplitude output).

6 kommentarer:

  1. You should not be so quick in using an argument with the second law the way you do.

    There is something called the fluctuation theorem discovered in the 1990's, giving the probability that a system will spontaneously decrease it's entropy and thus violating the second law during short times. This has been empirically demonstrated to hold.

    Using the second law as an argument in the way you do isn't valid.

  2. Well, if you speak for physics violating the 2nd law, I think you leave safe scientific ground and enter a swamp where anything can happen. Why would you like to do so?

  3. Did you bother to check the theory and experimental work I mentioned before dismissing it?

  4. I know about the fluctuation theorem, but I don't see that says anything about reality. There are many mathematical theorems without real physics content. Experimental verification of microscopic statistics is difficult, as pointed out by e.g. Einstein.

  5. The second law of thermodynamics is a statement about macroscopic systems. Right?

  6. Which 2nd law in which formulation?