How fast is a quantum jump

Abstract A proposal is put forward for an estimate of the duration of a transition between atomic states. The proposal rests on the consideration that a resonance of the atomic electron with modes of the zero-point radiation field of Compton's frequency is at the core of the phenomenon. The theoretical result, given essentially by the expression ( α ω C ) − 1 , where α is the fine structure constant and ω C the Compton angular frequency for the electron, lies well within the range of the recently experimentally estimated values of the order of attoseconds ( 10 − 18 s).