Analogue Quantum Gravity in Hyperbolic Metamaterials

Abstract

It is well known that extraordinary photons in hyperbolic metamaterials may be described as living in an effective Minkowski spacetime, which is defined by the peculiar form of the strongly anisotropic dielectric tensor in these metamaterials. Here, we demonstrate that within the scope of this approximation, the sound waves in hyperbolic metamaterials look similar to gravitational waves, and therefore the quantized sound waves (phonons) look similar to gravitons. Such an analogue model of quantum gravity looks especially interesting near the phase transitions in hyperbolic metamaterials where it becomes possible to switch quantum gravity effects on and off as a function of metamaterial temperature. We also predict strong enhancement of sonoluminescence in ferrofluid-based hyperbolic metamaterials, which looks analogous to particle creation in strong gravitational fields.

Gas Bubble Photonics: Manipulating Sonoluminescence Light with Fluorescent and Plasmonic Nanoparticles

“…Among different kinds of metamaterials, hyperbolic metamaterials have attracted a special attention since their hyperbolic dispersion relationship gives rise to useful effects including enhancement of spontaneous emission, negative refraction and ability to overcome the optical diffraction limit [120]. The concept of hyperbolic metamaterials has been extended to waves other than electromagnetic waves and light, where, in particular, it has been suggested that acoustic waves existing in hyperbolic metamaterials can be regarded as analogues of gravitational waves [122]. In this context and in light of the theoretical works [113,114] demonstrating a quantum nature of sonoluminescence, it has been suggested that the efficiency of sonoluminescence could be greatly enhanced using hyperbolic metamaterials and that studies of sonoluminescence processes in hyperbolic metamaterials could help search for quantum gravity effects [122].…”

“…The concept of hyperbolic metamaterials has been extended to waves other than electromagnetic waves and light, where, in particular, it has been suggested that acoustic waves existing in hyperbolic metamaterials can be regarded as analogues of gravitational waves [122]. In this context and in light of the theoretical works [113,114] demonstrating a quantum nature of sonoluminescence, it has been suggested that the efficiency of sonoluminescence could be greatly enhanced using hyperbolic metamaterials and that studies of sonoluminescence processes in hyperbolic metamaterials could help search for quantum gravity effects [122]. One suitable candidate for such experimental tests is a ferrofluid-based self-assembled hyperbolic metamaterial, where a chain of cobalt nanoparticles, which leads to formation of the hyperbolic metamaterial structure, and microbubbles are formed inside the ferrofluid after application of external magnetic field [123].…”

Electromagnetic energy density in hyperbolic metamaterials

“…Also, the resonant modes of HMMs with oscillators have been studied in waveguide structures 35 and cavity structures 36 , 37 . Interestingly, more recently, it has been shown that the propagation of sound waves in HMMs is similar to the gravitational waves, which means the quantized sound waves (phonons) are similar to gravitons 38 .…”