DMS Colloquium: Woden Kusner

Speaker: Wöden Kusner (University of Georgia)

Title: Measuring chirality with the wind (à la Lord Kelvin)

Abstract: The question of measuring "handedness" is of some significance in mathematics... and in the real world. Propellers and screws, proteins and DNA, in fact *almost everything* is chiral.  But we will defer to the chemists, who sometimes reduce this question to:

 "Are your shoes more left-or-right handed than a potato?" 

To address this question, we can begin with the hydrodynamic principle that chiral objects rotate when placed in a collimated flow. This leads to a trace-free tensorial chirality measure for space curves and surfaces, with a clear physical interpretation measuring twist. As a consequence, the "average handedness" of an object with respect to this measure will always be 0.  This also strongly suggests that a posited construction of Lord Kelvin--the isotropic helicoid--cannot exist.

This is joint work with Giovanni Dietler, Rob Kusner, Eric Rawdon, and Piotr Szymczak.

Faculty host:  Andras Bezdek

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