Non-Hermitian Bloch-Zener phase transition

Bloch-Zener oscillations (BZO), i.e., the interplay between Bloch oscillations and Zener tunneling in two-band lattices under an external direct current (DC) force, are ubiquitous in different areas of wave physics, including photonics. While in Hermitian systems such oscillations are rather generally aperiodic and only accidentally periodic, in non-Hermitian (NH) lattices BZO can show a transition from aperiodic to periodic as a NH parameter in the system is varied. Remark-ably, the phase transition can be either smooth or sharp, contrary to other types of NH phase transitions which are universally sharp. A discrete-time photonic quantum walk on a synthetic lattice is suggested for an experimental obser-vation of smooth BZO phase transitions. (c) 2022 Optica Publishing Group

Automated summary

Bloch-Zener oscillations, the interplay between Bloch oscillations and Zener tunneling in two-band lattices, are ubiquitous in wave physics. In non-Hermitian lattices, these oscillations can transition from aperiodic to periodic, and the phase transition can be either smooth or sharp, unlike other non-Hermitian phase transitions.