Author(s): Alexandre Chaduteau, Derek K. K. Lee, and Frank Schindler The recent topological classification of non-Hermitian “Hamiltonians” is usually interpreted in terms of pure quantum states that decay or grow with time. However, many-body systems with loss and gain are typically better described by mixed-state open quantum dynamics, which only correspond to pure-… [Phys. Rev. Lett. 136, 016603] Published Tue Jan 06, 2026