Interference of Thermal Electron Wavepackets
E.J. Heller and R.M. Westervelt

A thermal wavepacket has been sent from below, spreading out and bouncing against the two mirrors shown in the right and left portions of the image. After one bounce from the farther mirror, and two from the closer one, parts of the wavepacket are arriving at the same time back at the QPC. By moving the mirror slightly (about 1/4 of a deBroglie wavelength) the resulting interference from the two paths goes from destructive (left, less flux seen going down) to constructive (right, more flux going down).