2009 Advanced Laboratories Conference Abstract Detail Page

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Abstract Title: Angular momentum outside of the classical mechanics courses
Abstract: The angular momentum associated with "stationary" states in quantum mechanics is a source of confusion among undergraduates. A variety of experimental treatments provide opportunities for clarification, and we present three: a nuclear experiment demonstrating that a photon can have multiple h-bar of total angular momentum, along with optical and acoustic labs which demonstrate waves that carry spin and/or orbital angular momentum.

Since each photon has an intrinsic spin of one, it may surprise some that an individual photon can have multiple h-bar of angular momentum, yet this was established theoretically1 in nuclear physics in the 1940's, and was experimentally demonstrated2 almost as soon as detectors became available that used scintillators and photomultiplier tubes: by measuring the angular correlations between successive gamma-rays emitted, a (now standard) radioactive source of 60Co is shown to emit photons with total angular momentum greater than one h-bar. We complement this experiment with optical3 and acoustic4.5 labs that elucidate the nature of angular momentum in waves.

1 Hamilton, D R, Phys. Rev. 58, 122 (1940)
2 E. L. Brady and M. Deutsch, Phys. Rev. 78, 558 (1950)
3 Alicia V. Carpentier, et al., Amer. Jour. Phys. 76, 10 (Oct. 2008)
4 K. Volke-Sepulveda et al., Optical Trapping and Optical Micromanipulation IV, edited by Kishan Dholakia, Gabriel C. Spalding, Proc. of SPIE Vol. 6644, 66440Z (2007)
5 Karen Volke-Sepulveda, et al., Phys. Rev. Let. 100, 024302 (2008)
Abstract Type: Poster
Contributed Poster: Download the Contributed Poster
Session: Session IX - Effective Experiments Poster Session

Author/Organizer Information

Primary Contact: Nathan H. Frank
Augustana College
939 38th Street
Rock Island, IL 61201
Co-Author(s)
and Co-Presenter(s)
Gabriel C. Spalding,Illinois Wesleyan University, Bloomington, IL
gspaldin -at- iwu.edu