But to ensure that every electron makes the jump, you have to give each one precisely the right amount of energy. And the only way to do this is to bombard them with light at a whole range of energies. That way you can be pretty sure you'll get it spot on. Use these instead of normal light and Teich calculates that you only need photons at a single energy to do the same job. As they interact with the hydrogen atom, they seem to grab information about all of its electron states in one go.
Nothing seems safe from their prying wave function.
The initial indications of this possibility shocked the researchers. We had no idea that this would emerge from the math. Entangled photons have a wave function which includes information about the phase difference between them. To extract the information, you simply vary the degree of photon entanglement, for example by changing the electric field applied to your nonlinear crystal, or the delay time between the photons. Examples like this may be the first signs of a coming quantum revolution, when entities with strange properties will take over the tasks that have, until now, been the preserve of the predictable world of classical physics.