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math-ph2025
Scaling of the Lyapunov exponent at a balanced hyperbolic critical point
Joris De Moor, Christian Sadel, Hermann Schulz-Baldes
In both the random hopping model and at topological phase transitions in one-dimensional chiral systems, the Lyapunov exponent vanishes at zero energy, but is here shown to have an…
math-ph2025
Local topology for periodic Hamiltonians and fuzzy tori
Nora Doll, Terry Loring, Hermann Schulz-Baldes
A variety of local index formulas is constructed for quantum Hamiltonians with periodic boundary conditions. All dimensions of physical space as well as many symmetry constraints a…
math-ph2024
Transfer matrix analysis of non-hermitian Hamiltonians: asymptotic spectra and topological eigenvalues
Lars Koekenbier, Hermann Schulz-Baldes
Transfer matrix techniques are used to provide a new proof of Widom's results on the asymptotic spectral theory of finite block Toeplitz matrices. Furthermore, a rigorous treatment…