A formally exact real-space representation of the Berry phase on infinite lattices: Applications to dipole and quadrupole moments

Abstract: Inspired by Kitaev's real-space representation of Chern numbers, we develop a real-space formulation of the Berry phase for infinite lattices. While the well-known Resta formula for the Berry phase is defined under periodic boundary conditions for finite lattices, our approach constructs the Berry phase directly on an infinite lattice without requiring momentum-space discretization. We apply this method to several disordered models to examine its validity. Furthermore, we attempt to generalize the real-space representation to the quadrupole moment, drawing an analogy to the generalization of the Resta formula for the quadrupole moment.