April 20, 2015 from 2:15 p.m. in HG F 30

(aperitif after the lecture)

Prof. William T. M. Irvine
University of Chicago

Abstract:

Can you take a vortex loop – akin to a smoke ring in air – and tie it into a knot
or a link? The possibility of such knottiness in a fluid has fascinated physicists
and mathematicians ever since Kelvin¹s ‚vortex atom‘ hypothesis, in which the
atoms of the periodic table were hypothesized to correspond to closed vortex
loops of different knot types. More recently, the knottiness (Helicity) of a fluid
has re-emerged as a conserved quantity in many idealized situations (such as
Euler fluids and ideal plasmas) offering the potential for new fundamental
insights. In the real physical counterparts to these systems progress has however
been hindered by lack of accessible experimental systems. I will tell of
how to make a vortex knot and link in water, in the wave function of a superfluid
(on a computer) and of what happens thence. In particular I will talk
about how linking coiling and twisting interplay across scales.