Dr. H. Batelaan

University of Nebraska-Lincoln

Controlled double slit electron diffraction

102 Cardwell Hall

March 2, 2015

4:30 p.m.

Quantum interference explains the stability of matter, guided the construction of the laser, and led to many applications. So what is this quantum interference about? Feynman considered the double-slit experiments for electrons to contain "the only mystery", insofar as it concerns quantum interference [1]. To get as close to Feynman's description of double-slit diffraction we closed the individual slits on demand (see figure). Following Tonomura's famous interference build-up movie for a biprism wire [2], we also recorded a movie of the build-up of the diffraction pattern one particle at a time for the double slit [3]. In recent work done in Paris, macroscopic particle-wave duality with bouncing oil droplets was demonstrated for a double slit [4]. This was supposed not to be possible. What does that mean for microscopic or quantum-mechanical particle-wave duality for electrons? This means a lot to an international group of physicists labeled to be a "band of rebels" according to Morgan Freeman's show "Through the Wormhole" [5]. However this appears not to be the message presented in the past three years to many high school students through our educational movie "The Challenge of Quantum Reality" [6]. In the presentation this issue will be discussed.

[1] Feynman, R., Leighton, R. B. & Sands, M. L. Quantum Mechanics, vol. 3 (Addison Wesley, 1965).
[2] Demonstration of single-electron buildup of an interference pattern. Tonomura, A., Endo, J., Matsuda, T., Kawasaki, T. & Ezawa, H. Am. J. Phys. 57, 117{120 (1989).
[3] Controlled double-slit electron diffraction. R. Bach, D. Pope, S. H. Liou, H. Batelaan, Roger Bach et al., New J. Phys. 15 033018 (2013).
[4] Single-particle diffraction and interference at a macroscopic scale. Couder, Y. & Fort, E. Phys. Rev. Lett. 97, 154101 (2006).
[5] "How Does the UniverseWork". Through the Wormhole, With Morgan Freeman. Science Channel. 13 July 2011. Television.
[6] "The Challenge of Quantum Reality", www.perimeterinstitute.ca/outreach/teachers/class-kits/challenge-quantum-reality, http://www.youtube.com/watch?v=wihrAjFXg3o.