CPHT Condensed Matter Seminar
May 26 (Tuesday), 14:00, Room Jean Lascoux (CPHT)
Speaker: Fan Yang (Stockholm University)
Title: Non-Hermitian bulk-boundary correspondence: from open quantum systems to higher dimensions
Abstract: The anomalous bulk-boundary correspondence in non-Hermitian systems featuring an intricate interplay between skin and boundary modes has attracted enormous theoretical and experimental attention. Still, in quantum dynamics and in dimensions higher than one, this interplay remains much less understood. Here, we derive experimentally accessible signatures of non-Hermitian boundary modes and establish clear criteria that determine when bulk and boundary effects can be dynamically discerned using the Liouvillian separation gap [1]. Going to higher dimensions, we provide insights from exact analytical solutions of a large class of hypercubic models with open boundaries in every direction, and by tracking their topological origin [2]. Specifically, we show that amoeba theory accounting for the separation gaps of the bulk modes augmented with higher-dimensional generalizations of the biorthogonal polarization and the generalized Brillouin zone approaches accounting for the surface gaps of boundary modes provide a comprehensive understanding of these systems.
References:
[1] F. Yang, M. Zelenayova, P. Molignini, E. J. Bergholtz, arXiv:2506.16308 (2025).
[2] F. Yang, E. J. Bergholtz, Phys. Rev. Research 7, 023233 (2025).
Indéfini