Modulation spaces as a smooth structure in noncommutative geometry

Abstract

We demonstrate how to construct spectral triples for twisted group C^*-algebras of lattices in phase space of a second-countable locally compact abelian group using a class of weights appearing in time–frequency analysis. This yields a way of constructing quantum C^k-structures on Heisenberg modules, and we show how to obtain such structures using Gabor analysis and certain weighted analogues of Feichtinger’s algebra. We treat the standard spectral triple for noncommutative 2-tori as a special case, and as another example we define a spectral triple on noncommutative solenoids and a quantum C^k-structure on the associated Heisenberg modules.