So… I was just pondering the energy and particles in the universe.
It makes sense that matter is attracted to it's self by a gravitational force – it clumps and forms some kind of gravity superposition.
So what about antimatter – since charges are opposite, perhaps it also clumps together to form anti-gravity superpositions.
Is there such a thing as an anti-photon?
When a 'photon' interacts with an anti-atom, what happens?
Have there been any experiments to demonstrate any of these?
Best Answer
As Red Act says in a comment, gravity is too weak to be important on the scale of individual particles. However charge does group antiparticles together. For example an anti-proton and a positron will form an antihydrogen atom. In principle any antiatom can be made, but in the lab it's hard to stop antiparticles annihilating before they get the chance to combine to form antiatoms.
Even a particle and antiparticle can temporarily form a bound state. For example an electron and positron can bond to form positronium. However this is unstable and lasts ony about 100 picoseconds before the electron and positron annihilate. Similarly a quark and antiquark can bond to form a meson, and again these are unstable and decay via annihilation.
The photon is its own antiparticle. See the answers to Do anti-photons exist? for more.
The photon will interact with any electrically charged particle and it doesn't matter whether it's an antiparticle or not. So for example a photon will Compton scatter off a positron in the same way that it Compton scatters from an electron.