Topological lattice defects by groupoid methods and Kasparov’s KK-theory*
Topological lattice defects by groupoid methods and Kasparov’s KK-theory*
The bulk-boundary and a new bulk-defect correspondence principles are formulated using groupoid algebras. The new strategy relies on the observation that the groupoids of lattices with boundaries or defects display spaces of units with invariant accumulation manifolds, hence they can be naturally split into disjoint unions of open and closed …