Title: Physical manifestations of non-Hermiticity and topology in active and passive photonic systems
Abstract: In photonic systems, gain and loss can induce intriguing effects linked to non-Hermitian and topological physics. Prominent examples include sensing with a power-law response function, directed amplification, and symmetry-protected states that can be addressed through topological mode selection. I will describe the mechanisms by which these effects manifest in physical signatures and highlight the fundamental practical limits of their observability. While active systems suffer from noise, passive systems are constrained by causality.