The Quantum Challenge - Physics 302 2009 Recitation

This is the web site for the recitation for Physics 302 - Advanced Quantum Mechanics. Students from Chemistry 305: Physical Chemistry II and Physics 214: Introductory Quantum Mechanics are also invited to participate. In these classes the goal is to introduce you to the formalism of quantum mechanics and its power through calculation. The interpretive approach in such courses is typically ``Shut up and calculate!''.  By contrast, in this recitation we will explicitly discuss the interpretive problems of quantum mechanics with a focus on the experiments in which they arise. The goal is to read a fair chunk of the main text and many of the original experimental papers. The aim is not to solve the interpretive problems, but to understand what they are, and in which experiments do these interpretive issues arise.

The text for this recitation is The Quantum Challenge: Modern Research on the Foundations of Quantum Mechanics, Greenstein and Zajonc, Second edition. This is available from Amazon here, and the Haverford College bookstore has some copies. I will also be assigning reading from some of the original research articles cited - particularly those giving experimental details.

Meeting time
Because of the large number of students in Physics 302, and to encourage participation by students from the other classes this recitation will meet Sundays 3-4pm in Hilles 108

I would prefer to run this recitation as an extended discussion. The content we cover will be strongly tied to the book, and so you should ensure that you read the assignment from that book prior to coming to the recitation. I encourage you to read some of the other articles also. If we run out of things to say to each other we can resort to reading the assignments in class and trying to understand them together. Rather than try and stick to a schedule, I give below a list of topics we will cover. We will try to think deeply about each topic, and so the recitation will go at its own pace.

Topics and Reading assignments

Assignments from The Quantum Challenge are denoted TQC.

Preliminary reading to set the goals of the recitation.

TQC Preface, pp xi - xii.

TQC Prologue xiii-xviii.

Matter behaves as waves.  

TQC Chapter 1 - Matter Waves pp 1-21  

Reading from research articles giving experimental evidence for matter wave behavior in electrons, neutrons, atoms and Bose-Einstein Condensates.
  1. A. Tonomura and J. Endo and T. Matsuda and T. Kawasaki and H. Ezawa, Demonstration of single-electron buildup of an interference pattern, American Journal of Physics, 1989, 57, 2 pp117-120.  Journal Link. pdf. 
  2. Roland Gahler and Anton Zeilinger, Wave-optical experiments with very cold neutrons, American Journal of Physics, 1991, 59, 4, pp316-324. pdf
  3. O. Carnal, J. Mlynek, Young's double-slit experiment with atoms: A simple atom interferometer, Phys. Rev. Lett., 66, 21, pp2689--2692, (1991) pdf 
  4. Kasevich, Mark A., Coherence with Atoms, Science, 298, no. 5597 pp1363-1368 (2002) pdf
  5. Keith, David W. and Ekstrom, Christopher R. and Turchette, Quentin A. and Pritchard, David E., An interferometer for atoms, Phys. Rev. Lett. 66, 21, pp2693--2696, (1991) pdf
  6. Andrews, M. R. and Townsend, C. G. and Miesner, H.-J. and Durfee, D. S. and Kurn, D. M. and Ketterle, W., Observation of Interference Between Two Bose Condensates, Science, 275, no. 5300, pp637-641, (1997) pdf
  7. Wolfgang Ketterle, Nobel lecture: When atoms behave as waves: Bose-Einstein condensation and the atom laser,  Rev. Mod. Phys. 74, pp1131--1151, (2002) pdf
Article 1 and TQC pp 1-8 cover the creation of an electron interference pattern using an electron biprism to mimic a double slit setup. The de broglie wavelength of the electrons was 5 picometres. Not only were the interference patterns produced one electron at a time, the electrons could travel 100km in time between electrons arriving at the detector.

Article 2 and TQC p 8 cover the same experiment using first a gold and then a boron wire to split an aperture into two slits separated by 126 microns, as well as a range of other diffraction experiments with cold neutrons whose wavelength is around 20 angstroms. The time between successive neutrons was such that when one neutron was being detected, the next had not yet been produced in the nuclear reactor.

Note that the original evidence for the wave nature of electrons was the experiments of Davisson and Germer, and these experiments were performed independently of de Broglies theoretical proposal. Davisson and Germer's paper is:
C. J. Davisson and L. H. Germer, Diffraction of electrons by a crystal of nickel, Phys. Rev. 30 705-740 (1927) pdf

In fact - the electron interference experiment of Article 1 is not the first - the history is pointed out in this article.

Light behaves as particles

TQC Chapter 2 Photons pp 23-43

Reading on photon correlation experiments.
  1. R. Hanbury-Brown and R.Q. Twiss, Correlations between photons in two coherent beams of light.  Nature v 177 pp 27-29 (1956) pdf
  2. P. Grangier, G. Roger and A. Aspect, Experimental evidence for a photon anticorrelation effect on a beamsplitter, Europhysics Letters v 1 pp 173-179 (1986) pdf

Reading concerning the semi-classical treatment of the photo-electric effect
  1. Radiative Effects in Semiclassical Theory, Crisp, M. D. and Jaynes, E. T.,  Phys. Rev., 179, no 5, pp1253--1261, (1969), pdf
  2. Experimental distinction between the quantum and classical field-theoretic predictions for the photoelectric effect, Clauser, John F., Phys. Rev. D, v9 pp853--860, (1974) pdf
Reading concerning the semi-classical treatment of the Compton effect.
  1. J. Dodd The Compton effect - a classical treatment, European Jurnal of Physics, v4, pp 205-211 (1983) pdf
  2. J. Strand, The Compton effect - Schroedingers Treatment, European Journal of Physics v7 pp 217-221 (1986) pdf

The Uncertainty Principle

TQC Chapter 3 The Uncertainty principle.

The Pfleegor-Mandel experiment - One photon produced from two lasers pdf

The EPR Paradox

TQC Chapter 5 pp 123-133.

The original EPR paper - Can quantum mechanical description of reality be considered complete? pdf

Bohrs response to the EPR paper pdf