Zusammenfassung
We describe the role conformal nets, a mathematical model for conformal
field theory, could play in a geometric definition of the generalized
cohomology theory TMF of topological modular forms. Inspired by work
of Segal and Stolz-Teichner, we speculate that bundles of boundary
conditions for the net of free fermions will be the basic underlying
objects representing TMF-cohomology classes. String structures, which
are the fundamental orientations for TMF-cohomology, can be encoded
by defects between free fermions, and we construct the bundle of
fermionic boundary conditions for the TMF-Euler class of a string
vector bundle. We conjecture that the free fermion net exhibits an
algebraic periodicity corresponding to the 576-fold cohomological
periodicity of TMF; using a homotopy-theoretic invariant of invertible
conformal nets, we establish a lower bound of 24 on this periodicity
of the free fermions.
Nutzer