2024/07/14 by Weiwei Zhu, Zhu, Weiwei
Mathematics · #FOS: Physical sciences #Mathematics and Applications #Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
paper · pdf · doi:10.48550/arxiv.2407.13789
openalex publication_date 2024/07/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We report a new kind of exceptional points in periodically driven system, called Floquet π exceptional points, whose eigenvectors rotate on Bloch sphere and accumulate π geometric phase in one time period. The merging of two such kind exceptional points are constrained by their dynamical structure, meaning two order-1/2 exceptional points with same dynamical structure can merge to one order-1 one while those with opposite dynamical structure can not. We show they exist in Floquet bipartite lattices, and the order-1 Floquet π exceptional points appear at the phase transition point between quasimomentum gap phases and quasienergy gap phases. The scattering properties around the order-1 Floquet π exceptional points is quite novel, which is perfect transparency but detectable in reflection for one of two sides.