Orthogonal Analysis of Space-Time Crystals

This paper presents a space-time-wise orthogonal analysis of space-time crystals. This analysis provides a solution consisting of a pair of explicit parametric equations that result from a separate application of the Bloch-Floquet theorem in the (orthogonal) directions of space and time. Compared to previous approaches, this solution offers the benefits of greater simplicity, clearer emphasis on space-time duality and deeper physical insight.