Johannes Kellendonk

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Almost periodic chains (models for incommensurate phases) and
quasiperiodic chains (models for quasicrystals) have a richer
topological phase structure than periodic chains, due to the existence
of phasons. This effects the bulk boundary correspondence for these
models. We investigate in particular quasiperiodic chains where the
phason degree of freedom lives in a totally disconnected space. We show
how we can nevertheless define a winding number for the boundary
resonances and thus obtain an equation which relates the integrated
density of states at a gap to a winding number which can be interpreted
as the work the phason motion exhibits on the edge states of the system.

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Institut Camille Jordan (Lyon)
Stefan Cohn‐Vossen Raum des Mathematischen Instituts (Raum 313)
Contact: Christopher Max