9 papers
Mobile Exceptional Points Generate Momentum-Space Switching Domains
Jung-Wan Ryu, Chang-Hwan Yi
Exceptional points (EPs), non-Hermitian degeneracies where both eigenvalues and eigenvectors coalesce, play a central role in the topology of non-Hermitian spectra. Recent advances…
Biorthogonal scattering and generalized unitarity in non-Hermitian systems
Jung-Wan Ryu, Henning Schomerus, Hee Chul Park
We investigate the two-port scattering process in non-Hermitian dimer models via quantum measurements using external leads. We focus on two exemplary dimer models that preserve par…
Spontaneous emission decay and excitation in photonic time crystals
Jagang Park, Kyungmin Lee, Ruo-Yang Zhang +10
Over the last few decades, the predominant strategies for controlling spontaneous emission have involved tailoring the spatial surroundings of quantum emitters or atoms to create r…
Nonreciprocity induced spatiotemporal chaos: Reactive vs dissipative routes
Jung-Wan Ryu
Nonreciprocal interactions fundamentally alter the collective dynamics of nonlinear oscillator networks. Here we investigate Stuart-Landau oscillators on a ring with nonreciprocal…
A unified framework for exceptional point pairs in non-Hermitian two-level systems
Jung-Wan Ryu, Jae-Ho Han, Chang-Hwan Yi
Exceptional points (EPs) in non-Hermitian systems are branch singularities where eigenvalues and eigenvectors simultaneously coalesce, leading to rich topological phenomena beyond…
Non-orientable Exceptional Points in Twisted Boundary Systems
Jung-Wan Ryu, Jae-Ho Han, Moon Jip Park +2
Non-orientable manifolds, such as the Möbius strip and the Klein bottle, defy conventional geometric intuition through their twisted boundary conditions. As a result, topological…