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cond-mat.mes-hall2024
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.…
quant-ph2024
Graph-theoretical approach to the eigenvalue spectrum of perturbed higher-order exceptional points
Daniel Grom, Julius Kullig, Malte Röntgen +1
Exceptional points are special degeneracy points in parameter space that can arise in (effective) non-Hermitian Hamiltonians describing open quantum and wave systems. At an n-th or…
cond-mat.str-el2024
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…