# Adiabatic quantum evolution of single photon or biphoton system

The prerequisite for adiabatic quantum evolution of single photon or biphoton system is as follows.

We have to prepare a single photon or biphoton quantum system which has a ground and a higher level energy state. Is that allowed in physics?

If we consider a single photon quantum system, higher energy means higher frequency. So, the Hamiltonian of the system should have two eigenvalues, one for the ground level and at least one other for the first excited state.

What will the Hamiltonian look like?

-
Any help from anyone? –  Omar Shehab Aug 1 '13 at 20:57
I think just simple potential well can work. –  Ali Aug 3 '13 at 1:23
@Ali, is it possible to trap a photon or biphoton in a potential well? –  Omar Shehab Aug 3 '13 at 4:58
If we had perfect mirrors, you could trap photons between them, which would be an infinite potential well for them. However perfect mirrors do not really exist; and photons trapped between them will shortly annihilate. Also it's not easy to measure photon's state, whenever you want to do a measurement. Anyway, the point of my comment isn't to provide a realistic model, it's pointing at your "Is it allowed in physics" question; where the answer is yes. –  Ali Aug 3 '13 at 6:02
You might find Birefringence appropriate as well. You can prepare a photon with a desired polarization, and then send it through these crystals, which have different potentials regarding the polarization. –  Ali Aug 7 '13 at 15:01