title: Defect coalescence in spherical nematic shells.
abstract: We study coalescence of topological defects in nematic liquid crystals confined to spherical shells using both experiments and computer simulations. We observe that the four s=+1/2 defects that are present due to topological constraints imposed by the spherical geometry coalesce by pairs after changing the molecular orientation at the outer surface from tangential to perpendicular; the result is the formation of two single s=+1 defects. It is noteworthy that the speed of the coalescence process is peaked when the defects are at opposite points on the equator of the shell; this maximum results from the thickness inhomogeneity of the shells.
authors.affiliation: School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
authors.forename: Teresa
authors.initials: T
authors.lastname: Lopez-Leon
authors.forename: Martin A
authors.initials: MA
authors.lastname: Bates
authors.forename: Alberto
authors.initials: A
authors.lastname: Fernandez-Nieves