Replicating physical motion with Minkowskian isorefractive spacetime crystals

Here, we show that isorefractive spacetime crystals with a travelling-wave modulation may mimic rigorously the response of moving material systems. Unlike generic spacetime crystals, which are characterized by a bi-anisotropic coupling in the co-moving frame, isorefractive crystals exhibit an observer-independent response, resulting in isotropic constitutive relations devoid of any bianisotropy. We show how to take advantage of this property in the calculation of the band diagrams of isorefractive spacetime crystals in the laboratory frame and in the study of the synthetic Fresnel drag. Furthermore, we discuss the impact of considering either a Galilean or a Lorentz transformation in the homogenization of spacetime crystals, showing that the effective response is independent of the considered transformation.

Automated summary

In this study, it is demonstrated that isorefractive spacetime crystals with a travelling-wave modulation can rigorously mimic the response of moving material systems. Unlike generic spacetime crystals, which exhibit bi-anisotropic coupling in the co-moving frame, isorefractive crystals show an observer-independent response, resulting in isotropic constitutive relations without any bianisotropy. The researchers show how this property can be utilized in calculating the band diagrams of isorefractive spacetime crystals in the laboratory frame and studying synthetic Fresnel drag. Additionally, the impact of considering either a Galilean or a Lorentz transformation in the homogenization of spacetime crystals is discussed, revealing that the effective response is independent of the transformation considered.