Using Classical Mechanics Reasoning to Introduce Quantum Ideas

By emphasizing similarities between classical and quantum mechanics, rather than the differences, quantum ideas can be introduced into the introductory class curriculum. At Georgetown University, we have begun doing this by putting emphasis on building upon the classical physics that the students already know. In this workshop, we will show content from two classes worth of material to develop what a single photon is and how we do experiments with them. Participants will have opportunities to try some activities through student worksheets.

We start with a discussion of the photoelectric effect, and emphasize how it would be described by a classical model of a metal and how the model fails with respect to the experimental data. Then, using the photoelectric effect to provide single-photon sensitivity, we describe how one can detect individual photons. Finally, we construct the so-called G2 experiment, which verifies how single photon sources are truly quantum sources of light with distinctly different behavior from dim classical light (like a dim laser). Along the way, students will refresh their memories on concepts such as the driven harmonic oscillator, resonance, voltage and electric fields, and reasoning using ideas from conservation of energy. Students should emerge with a clear grasp of what a single photon's properties are and how the quantum ideas emerge from, but are different from their classical intuitions.

This workshop is offered free of charge and will be virtual using Zoom.

Facilitator: Jim Freericks (Georgetown University, AAPT Treasurer)

Resources:

• Presentation Slides
• Worksheet about the Photoelectric Effect, using the PhET simulation
• Worksheet about the G2 Experiment