Comment by gradientsrneat

In an atom, the electrons orbiting the nucleus are only allowed to be at discrete energy levels (the energy levels are "quantized"). In a classical model of an orbit, the energy level of a spaceship orbiting a planet can be thought of as the speed it has that allows it to orbit at a certain altitude, assuming no friction or other effects. Velocity is energy in that case (E=m*v^2 in classical mechanics). Unlike electrons in an atom, the spaceship can be in any one of a continuous range of energy levels (up to escape velocity).

The proposal in the article is (I think) that bosons orbit certain black holes in quantized energy states, like electrons would orbit an atomic nucleus.