Everyone learns the picture associated with e.g. the Balmer series in Hydrogen: a photon with a precise energy flies in and is absorbed by an electron which is excited into a higher energy state, which then decays to the ground state, re-radiating a photon of that precise frequency. If we stop thinking about these as billiard balls, are stranger effects possible? e.g. If we tuned a photon to have twice the energy difference between the ground and 1st excited states of the Helium atom, could we excite both electrons into the higher state simultaneously? What about the particles in a Bose-Einstein condensate, whose De Broglie wavelengths overlap (if a dim memory serves me well)- could we excite multiple particles into the first state with a single photon? Thanks in advance.