Multi‐Slit Diffraction in Scaled Space‐Time

ABSTRACT We revisit multi‐slit diffraction with a scaling of space and time to exploit an equivalence of wave packets describing quantum free and harmonic oscillator (HO) motion. We introduce a co‐moving frame of space and time coordinates to define an effective, time‐independent, HO potential that confines and directs initially displaced wave packets along the classical phase space of the oscillator. ‐slit diffraction in the lab frame from the slits to a distant detector and the familiar spreading of the propagating wave front is then described as the propagation of HO wave packets over just a quarter cycle of the oscillator and confined to the HO potential well. We show that diffraction features are preserved in the co‐moving frame and well characterized in both the near and far fields by the classical trajectories of the HO phase space.