University of Minnesota
School of Physics & Astronomy

History of Science and Technology/Minnesota Center for Philosophy of Science Colloquium

Friday, October 30th 2009
Speaker: Michel Janssen, Program in History of Science and Technology, University of Minnesota
Subject: Inside the Black(body) Box: Jordan on the Wave-Particle Duality of Light
Refreshments served in Room 216 Physics at 3:15 p.m.

In 1909, Albert Einstein derived a formula for the mean square energy fluctuation in a small subvolume of a box filled with blackbody radiation. This formula is the sum of a wave term and a particle term. In a famous joint paper with Max Born and Werner Heisenberg submitted in late 1925, Pascual Jordan used the new matrix mechanics to show that one recovers both these terms in a simple model of quantized waves. So, contrary to what Einstein had concluded in 1909, the two terms do not require separate wave and particle mechanisms, but arise from a unified dynamical framework. This result not only solved Einstein's puzzle about the wave-particle duality of light, it also provided striking evidence for matrix mechanics, and can be seen as a strong argument for field quantization. After a brief review of Einstein's early work on fluctuations in blackbody radiation, I will present Jordan's result and the curious story of its reception. Rather than being hailed as a major contribution to quantum theory, Jordan's result met mostly with skepticism, even from his co-authors. I will argue that the skeptics were wrong. This talk is based on a joint paper with Anthony Duncan, "Pascual Jordan's resolution of the conundrum of the wave-particle duality of light." Studies in History and Philosophy of Modern Physics 39 (2008): 634-666.

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