Eric G. Adelberger
Department of Physics
University of Washington

Colloquium

Sub-millimeter Tests of the Gravitational Inverse Square Law:
a Search for "Large" Extra Dimensions

It is remarkable that questions about gravitation, the oldest known interaction in physics, are again at the center of physics and that small-scale experiments can address important open issues. Modern string theory ideas (new scalar particles and extra dimensions) hint that both Einstein's Equivalence Principle and Newton's Inverse-Square Law may not be exact. I will discuss motivations (large-extra dimensions, a small cosmological constant), techniques (torsion and beam balances), and results of such tests, emphasizing the Eot-Wash group's recent tests of the Inverse-Square Law for length scales down to 100 micrometers.

Seminar: Tuesday 25 September 2001, 1:30 pm DRL 2N36

Torsion balance tests of fundamental issues:
the weight of gravity, the possible role of scalar fields,
and limits on CPT violation in the electron sector.

Torsion balances provide a highly sensitive technique for probing extensions of the two standard models--of particle physics and of gravity. I will discuss sensitive Eot-Wash group results on the weight of gravity itself (i.e. the Equivalence Principle for gravitational self-energy), tests for non-gravitational (i.e. Equivalence-Principle violating) interactions between dark and luminous matter, and for CPT violation in the electron sector.