“Non-Hermitian localization phenomena”

by Mária Zelenayová (Stockholm University)

Wednesday 17 Sept 2025, 09:00 → 11:00 Europe/Stockholm

A4:3001 (AlbaNova Main Building)

Abstract: 
In Hermitian systems, there is one type of mode localized at the boundary, known as a 
boundary mode. In certain materials, such modes can be protected by the inherent properties 
of the system, referred to as the system’s topology. In non-Hermitian systems, however, there 
are two distinct types of boundary modes. The first arises from bulk states that accumulate at 
one boundary of the system—a phenomenon with no counterpart in Hermitian systems. The 
second is a non-Hermitian analog of the conventional Hermitian boundary mode. Crucially, 
the interplay between these two flavors gives rise to several localization phenomena absent in 
Hermitian systems, which we address in the first part of this thesis. Moreover, non-Hermitian 
systems naturally arise in systems with dissipation, known as open quantum systems. A well?known description of such systems is provided by the Lindblad master equation, in which the 
system’s dynamics is governed by the Liouvillian. In the dynamics of dissipative systems, the 
individual roles of the two flavors of boundary modes is less clear, and we address this 
question in the second part of this thesis.