Extraordinary light rays propagating inside a hyperbolic metamaterial look similar to particle world lines in a 2+1 dimensional Minkowski spacetime. 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.
Igor I. Smolyaninov, Bradley Yost, Evan Bates, and Vera N. Smolyaninova, “Experimental demonstration of metamaterial “multiverse” in a ferrofluid,” Optics Express 21, 014918 (2013).
- This work generated considerable media interest including MIT Technology Review, ExtremeTech, The Econimist, etc.
![Image%20multiverse[1]](https://wp.towson.edu/vsmolyan/files/2016/05/Image20multiverse1-18dsdsv.jpg)
Supported in part by NSF grant DMR-1104676