David J. Griffiths
Emeritus Professor of Physics, Reed College
Author of: Classical Electrodynamics, Quantum Mechanics, Elementary Particles.
Hidden momentum, field momentum, and
electromagnetic impulse.
ABSTRACT: Electromagnetic fields carry energy, momentum, and
angular momentum. The momentum density accounts (among other
things) for the pressure of light. But even STATIC fields can carry
momentum, and this would appear to contradict a general theorem
that the total momentum of a closed system is zero if its center of
energy is at rest. In such cases there must be some other (nonelectromagnetic) momentum to cancel the field momentum. What is
the nature of this "hidden" momentum and what happens to it when
the electromagnetic fields are turned off?
January 20th
Higgins Hall 300
4:00 PM
REFRESHMENTS
Higgins Hall 235
2nd floor Physics, 3:00 PM
Accessible to all graduate students, and advanced undergraduates.