Experimental model of topological defects in Minkowski spacetime based on disordered ferrofluid: magnetic monopoles, cosmic strings and the spacetime cloak

TL;DR

This paper presents an experimental model using disordered ferrofluid to simulate topological defects in Minkowski spacetime, such as magnetic monopoles, cosmic strings, and spacetime cloaks, through self-assembled hyperbolic metamaterials.

Contribution

It introduces a microscopic study linking ferrofluid nanoparticle defects to spacetime topological defects, providing experimental observations of these phenomena.

Findings

Ferrofluid forms hyperbolic metamaterials with Lorentz symmetry.

Defects in nanoparticle chains mimic spacetime topological defects.

Experimental evidence of monopole-like and string-like defects.

Abstract

Cobalt nanoparticle-based ferrofluid in the presence of external magnetic field forms a self-assembled hyperbolic metamaterial. Wave equation describing propagation of extraordinary light inside the ferrofluid exhibits 2+1 dimensional Lorentz symmetry. The role of time in the corresponding effective 3D Minkowski spacetime 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 spacetime defects as magnetic monopoles, cosmic strings and the recently proposed spacetime cloaks. Experimental observations of such defects are described.