Comment by echelon

- my understanding of nonlinear optical mediums is negligible. Something like the crystals that cause quantum entanglement and emitting photon pairs?

- what is a "photon gas"? Is this a state of matter? What is the matter if photons aren't matter?

- ideal gas law, PV=nRT not obeyed? Due to ionization or something? Photon pressure?

- Joule-Thompson Effect?

- Building computers out of light?

- Which thermodynamic properties or laws are being obeyed? Is this something like a Carnot cycle, but with photons?