Abstract By dealing with an elastic medium with a disclination, we search for the influence of the disclination topology on a geometric quantum phase yielded by the interaction of a nonuniform magnetic field with the permanent electric dipole moment of a neutral particle. This magnetic field is produced by a nonuniform electric current density. Further, we explore the non-Abelian nature of the geometric quantum phase in search of quantum holonomies for this neutral particle system and discuss a possible application to the geometric quantum computation.
Two-dimensional higher-order topological insulators can display a number of exotic phenomena, such as half-integer charges localized at both corners and disclination defects. In this paper, we analyze these phenomena, focusing on the paradigmatic example of the quadrupole insulator with
C4 rotation symmetry, and present a topological field theory description of the mixed geometry-charge responses. Our theory provides a unified description of the corner and disclination charges in terms of a physical geometry (which encodes disclinations), and an effective geometry (which encodes corners). We extend this analysis to interacting systems, and predict the response of fractional quadrupole insulators, which exhibit charge
e/2(2k+1) bound to corners and disclinations.