71 citations · 182 across the 11 of their papers we have counts for
12 papers
Ubiquitous topological materials protected by hidden partial symmetries
Lumen Eek, Xuelong Chen, Malte Röntgen +2
Symmetries play a crucial role in protecting the topological phases of insulators, ensuring the robustness of their surface states against perturbations. Traditionally, these symme…
Higher-order topology protected by latent crystalline symmetries
L. Eek, M. Röntgen, A. Moustaj +1
We demonstrate that rotation symmetry is not a necessary requirement for the existence of fractional corner charges in Cn-symmetric higher-order topological crystalline insulators.…
Emergent non-Hermitian models
Lumen Eek, Anouar Moustaj, Malte Röntgen +3
The Hatano-Nelson and the non-Hermitian Su-Schrieffer-Heeger model are paradigmatic examples of non-Hermitian systems that host non-trivial boundary phenomena. In this work, we use…
The Fractal-Lattice Hubbard Model
Monica Conte, Vinicius Zampronio, Malte Röntgen +1
Here, we investigate the fractal-lattice Hubbard model using various numerical methods: exact diagonalization, the self-consistent diagonalization of a (mean-field) Hartree-Fock Ha…
Equireflectionality and customized unbalanced coherent perfect absorption in asymmetric waveguide networks
Malte Röntgen, Olivier Richoux, Georgios Theocharis +4
We explore the scattering of waves in designed asymmetric one-dimensional waveguide networks. We show that the reflection between two ports of an asymmetric network can be identica…
Covert Scattering Control in Metamaterials with Non-Locally Encoded Hidden Symmetry
Jérôme Sol, Malte Röntgen, Philipp del Hougne
Symmetries and tunability are of fundamental importance in wave scattering control, but symmetries are often obvious upon visual inspection which constitutes a significant vulnerab…
Spectral Properties of Two Coupled Fibonacci Chains
Anouar Moustaj, Malte Röntgen, Christian V. Morfonios +2
The Fibonacci chain, i.e., a tight-binding model where couplings and/or on-site potentials can take only two different values distributed according to the Fibonacci word, is a clas…
Latent symmetry induced degeneracies
M. Röntgen, M. Pyzh, C. V. Morfonios +3
Degeneracies in the energy spectra of physical systems are commonly considered to be either of accidental character or induced by symmetries of the Hamiltonian. We develop an appro…
Compact localized states of open scattering media
Fabrizio Sgrignuoli, Malte Rontgen, Christian V. Morfonios +2
We study the compact localized scattering resonances of periodic and aperiodic chains of dipolar nanoparticles by combining the powerful Equitable Partition Theorem (EPT) of graph…
Edge Modes of Scattering Chains with Aperiodic Order
Ren Wang, Malte Rontgen, Christian V. Morfonios +3
We study the scattering resonances of one-dimensional deterministic aperiodic chains of electric dipoles using the vectorial Green's matrix method, which accounts for both short- a…
Compact localized states and flat bands from local symmetry partitioning
M. Röntgen, C. V. Morfonios, P. Schmelcher
We propose a framework for the connection between local symmetries of discrete Hamiltonians and the design of compact localized states. Such compact localized states are used for t…
Non-Local Currents and the Structure of Eigenstates in Planar Discrete Systems with Local Symmetries
Malte Röntgen, Christian V. Morfonios, Fotios Diakonos +1
Local symmetries are spatial symmetries present in a subdomain of a complex system. By using and extending a framework of so-called non-local currents that has been established rec…