"Probability Densities and Newton's Laws"
(Why didn't Newton think about the probability of getting hit on the
head when he sat under the apple tree?)
Professor L.J. Curtis
University of Toledo
Abstract
A significant distinction exists between the conceptual frameworks used
in introductory physics courses and in subsequent courses for physics
majors. Although the distinction is often characterized as "classical"
vs "quantum mechanical,'' the primary difference is not due to
quantization. Instead it is a nonessential tendency to describe
macroscopic systems by instantaneous values for position, speed, and
acceleration, and microscopic systems by time-averaged position
probability densities. This produces a serious disconnect between
physics as it is practiced, and as it is taught to non-physicists(and
hence between physics and society). Alternatives to this framework will
be discussed involving a simple, pedagogically transparent use of
position probability densities (and optional semiclassical quantization)
to describe both macroscopic and microscopic systems.