Experimental demonstration of metamaterial multiverse in a ferrofluid

TL;DR

This paper demonstrates experimentally how thermal fluctuations in a ferrofluid can transiently create hyperbolic metamaterial regions resembling multiverse universes, linking optical properties to cosmological models.

Contribution

It introduces the concept of a ferrofluid-based metamaterial exhibiting transient hyperbolic regions due to thermal fluctuations, bridging optics and cosmology.

Findings

Thermal fluctuations induce transient hyperbolic regions in ferrofluid.

Experimental polarization-dependent transmission measurements support the theoretical model.

Ferrofluid fluctuations mimic creation and disappearance of Minkowski spacetimes.

Abstract

Extraordinary light rays propagating inside a hyperbolic metamaterial look similar to particle world lines in a 2+1 dimensional Minkowski spacetime [1]. Magnetic nanoparticles in a ferrofluid are known to form nanocolumns aligned along the magnetic field, so that a hyperbolic metamaterial may be formed at large enough nanoparticle concentration nH. Here we investigate optical properties of such a metamaterial just below nH. While on average such a metamaterial is elliptical, thermal fluctuations of nanoparticle concentration lead to transient formation of hyperbolic regions (3D Minkowski spacetimes) inside this metamaterial. Thus, thermal fluctuations in a ferrofluid look similar to creation and disappearance of individual Minkowski spacetimes (universes) in the cosmological multiverse. This theoretical picture is supported by experimental measurements of polarization-dependent optical transmission of a cobalt based ferrofluid at 1500 nm.