What is the problem of mass for quantum Yang-Mills theory?

Wednesday, 21 March, 2007 at 14:30 in Auditorium F at the Department of
Mathematical Sciences, Faculty of Science, University of Aarhus.

Abstract: The problem, mentioned in the title,
is listed as one of the Millenium Problems by the Clay Mathematical
Institute. To the wide mathematical audience it is much less known
than the other six problems. I shall try to explain its formulation
and argue that it deserves to be in this list.

Three dimensional Knot-like solitons and their hypothetical
role in quantum Yang-Mills theory

Thursday, 22 March, 2007 at 14:30 in Auditorium F at the
Department of Mathematical Sciences, Faculty of Science, University
of Aarhus.

Abstract:
It is a general belief that, in Quantum Chromodynamics, quarks are
connected by strings composed of Yang-Mills fields. A natural
question is what happens to these strings if the quarks are
absent, so we deal with pure Yang-Mills quantum theory. It is
argued that among the variables, describing the Yang-Mills fields,
there are those, corresponding to nonlinear systems, allowing the
solitons to concentrate along closed knotted rings. These
excitations could be the remnants of the QCD strings.