title: Experimental model of topological defects in Minkowski space-time based on disordered ferrofluid: magnetic monopoles, cosmic strings and the space-time cloak.
abstract: In the presence of an external magnetic field, cobalt nanoparticle-based ferrofluid forms a self-assembled hyperbolic metamaterial. The wave equation, which describes propagation of extraordinary light inside the ferrofluid, exhibits 2+1 dimensional Lorentz symmetry. The role of time in the corresponding effective three-dimensional Minkowski space-time is played by the spatial coordinate directed along the periodic nanoparticle chains aligned by the magnetic field. Here, we present a microscopic study of point, linear, planar and volume defects of the nanoparticle chain structure and demonstrate that they may exhibit strong similarities with such Minkowski space-time defects as magnetic monopoles, cosmic strings and the recently proposed space-time cloaks. Experimental observations of such defects are described.
authors.affiliation: Department of Electrical and Computer Engineering, University of Maryland, College Park, MD 20742, USA smoly@umd.edu.
authors.forename: Igor I
authors.initials: II
authors.lastname: Smolyaninov
authors.affiliation: Department of Physics, Astronomy and Geosciences, Towson University, 8000 York Road, Towson, MD 21252, USA.
authors.forename: Vera N
authors.initials: VN
authors.lastname: Smolyaninova
authors.affiliation: Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA 92093, USA.
authors.forename: Alexei I
authors.initials: AI
authors.lastname: Smolyaninov
keywords: ferrofluid; hyperbolic metamaterial; space–time defects