The Double Slit Experiment for Electrons

Scot McGregor, Roger Bach, Adam Caprez +3 more

dong ZHANG

Young’s double-slit experiment was first demonstrated with light and was later extended to electrons and other particles. These experiments share a common geometry: something approaches the slits, passes through them, and produces an interference pattern afterward. However, monochromatic water waves, electrons, and photons are physically different, and their interactions with a real slit need not be the same. Most discussions of the double-slit experiment focus on the interference pattern collected on a screen after the slits. Some descriptions also consider what happens before the slits, including the role of an eraser or observer and the splitting of an electron or photon to interfere with itself. Much less attention is given to what happens while an electron or photon is passing through a real slit. A real slit has thickness and is made of matter. Its surfaces contain atoms, electrons, and nuclei and therefore provide an electromagnetic environment through which an electron or photon passes. An electron or photon enters the slit, travels between its surfaces, and leaves it. This raises a missing question: can an electron or photon interact with this electromagnetic environment while passing through the slit, and can such an interaction affect its motion, particularly its exiting direction? We examine experimental evidence together with geometrical and accumulated-count evidence, including the observed spacing of interference maxima, the nonlinear geometry of constant-path-difference loci, the finite number and different possible counts of interference fringes, and the accumulation of individual detection events. Figures derived from the corresponding experimental and geometrical constructions are used to make these distinctions explicit. These results motivate a global description of Young’s double-slit experiment in three physically connected regions: pre-slit, in-slit, and post-slit. We call this the global trilogy of Young’s double-slit experiment. The global trilogy places the physical slit and its electromagnetic environment explicitly between the familiar pre-slit and post-slit descriptions and provides a framework for investigating the complete process from source, through the slit, to interference and detection.

Benjamin Bähr, Boris Lemmer, Rina Piccolo

John Wickham Steeds, Pier Giorgio Merli, Giulio Pozzi +2 more

The article "A brief history of the double-slit experiment" (September 2002 p15; correction October p17) describes how Claus Jönsson of the University of Tübingen performed the first double-slit interference experiment with electrons in 1961. It then goes on to say: "The next milestone – an experiment in which there was just one electron in the apparatus at any one time – was reached by Akira Tonomura and co-workers at Hitachi in 1989 when they observed the build-up of the fringe pattern with a very weak electron source and an electron biprism (Am. J. Phys. 57 117–120)."

Peter V. Raktoe

Hiroo Hongo, Yasuyuki Miyamoto, Kazuhito Furuya +1 more

We report a double-slit experiment of hot electrons in a semiconductor under a magnetic field. The pitch of the double slit buried in the semiconductor is 40 nm and the electron energy is of the order of 100 meV. By applying a magnetic field, the change in current that passes through the slits is observed at the segmented collector. The measured current shows a clear minimum around B=0 T, with this behavior agreeing with a theoretical calculation based on double-slit interference. Quantitative estimation is consistent with this order of current variation. We think that these results show evidence of the observation of hot electron interference by a double slit in a semiconductor.