Photon collision physics???

Blogical

Can anybody explain the physics behind the collision of two photons if they do collide, also what are the phenomenon which arise due to this collision, do such collisions have any impact in experiments in quantum physics involving photons!

A Dhingra

hi...
Though i am not sure , but reading your question it occurred to me as if you are talking about two photons hitting each other.....May be to interfere (create an interference pattern), though this is a wave phenomenon as per classical physics. But quantum should be able to digest this...
I am looking forward to an answer to your question, because it is definitely interesting.

Bill_K

Photons interact directly only with objects that are charged, so there is no direct interaction between two photons. Photon-photon scattering in principle can occur indirectly through the creation of virtual particles such as electron-positron pairs. See this diagram. Such processes have been studied but never observed experimentally since the cross-section is very small.

mathman

Right after the big bang photon-photon collisions were quite common leading to various particle-antiparticle pairs.

http://en.wikipedia.org/wiki/Big_Bang

Bill_K

Could you please quote the part in this Wikipedia page where photon-photon collisions are mentioned.

strangerep

Regarding observation of photon-photon scattering processes (and/or close cousins thereof),
see http://en.wikipedia.org/wiki/Delbruck_scattering

mathman

The earliest phases of the Big Bang are subject to much speculation. In the most common models the Universe was filled homogeneously and isotropically with an incredibly high energy density and huge temperatures and pressures and was very rapidly expanding and cooling. Approximately 10−37 seconds into the expansion, a phase transition caused a cosmic inflation, during which the Universe grew exponentially.[18] After inflation stopped, the Universe consisted of a quark–gluon plasma, as well as all other elementary particles.[19] Temperatures were so high that the random motions of particles were at relativistic speeds, and particle–antiparticle pairs of all kinds were being continuously created and destroyed in collisions. At some point an unknown reaction called baryogenesis violated the conservation of baryon number, leading to a very small excess of quarks and leptons over antiquarks and antileptons—of the order of one part in 30 million. This resulted in the predominance of matter over antimatter in the present Universe.[20]

My underline. Creation resulted from photon-photon collisions.