Exploring exceptional points and their impact on magnetic bilayers

The advent of exceptional points (EPs) has revitalized the field of photonics, particularly in magnetic systems where non-Hermiticity arises naturally from damping and anti-damping effects. In this presentation, I will first illustrate how EPs in magnetic systems act as indicators of dynamical phase transitions. Specifically, we observe the emergence of a periodic oscillating dynamical phase within regions bounded by EPs in antiferromagnetically coupled bilayers, offering potential applications as large-amplitude magnetic nano-oscillators. In the subsequent section, I will reveal the occurrence of numerous EPs throughout the first Brillouin zone in a van der Waals ferromagnetic bilayer. Our study further uncovers a wavevector-dependent pseudo-Hermiticity symmetry, ensuring the magnon spectrum remains real or forms conjugate pairs, thus enriching our understanding and control of magnetic systems.