Recent Developments in Quantum Mechanics

Abstract

The fundamental fact for quantum physics which has emerged from experimental investigations in the field is a double duality of wave and particle concepts. The wave theory of light, firmly grounded by the wave explanations of interference and diffraction and by Maxwell’s electromagnetic theory of light waves, is now recognized as giving but one aspect of the nature of radiation. The corpusclar aspect of radiation is revealed in the photoelectric effect and in the Compton effect. In these effects Planck’s constant appears as a universal constant which connects the wave and particle modes of description of the same radiation.

Based on a lecture delivered on July 19, 1928, before the summer school for engineering teachers of the Society for the Promotion of Engineering Education at the Massachusetts Institute of Technology, Cambridge.