Smolyaninov Igor I, Yost Bradley, Bates Evan, Smolyaninova Vera N
Department of Electrical and Computer Engineering, University of Maryland, College Park, MD 20742, USA.
Opt Express. 2013 Jun 17;21(12):14918-25. doi: 10.1364/OE.21.014918.
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.
在双曲型超材料内部传播的非凡光线，看起来类似于二维加一维闵可夫斯基时空中的粒子世界线。已知铁磁流体中的磁性纳米粒子会形成沿磁场排列的纳米柱，因此在足够大的纳米粒子浓度nH下可能会形成双曲型超材料。在此，我们研究这种超材料在略低于nH时的光学性质。虽然平均而言这种超材料是椭圆形的，但纳米粒子浓度的热涨落会导致在这种超材料内部瞬态形成双曲区域（三维闵可夫斯基时空）。因此，铁磁流体中的热涨落看起来类似于宇宙学多元宇宙中单个闵可夫斯基时空（宇宙）的产生和消失。这种理论图景得到了钴基铁磁流体在1500纳米处偏振相关光传输的实验测量结果的支持。
