73 citations · 523 across the 34 of their papers we have counts for
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Quantum Monodromy in the Isotropic 3-Dimensional Harmonic Oscillator
Irina Chiscop, Holger R. Dullin, Konstantinos Efstathiou +1
The isotropic harmonic oscillator in dimension 3 separates in several different coordinate systems. Separating in a particular coordinate system defines a system of three commuting…
Non-abelian nature of systems with multiple exceptional points
Eric J. Pap, Daniël Boer, Holger Waalkens
The defining characteristic of an exceptional point (EP) in the parameter space of a family of operators is that upon encircling the EP eigenstates are permuted. In case one encirc…
Scattering invariants in Euler's two-center problem
Nikolay Martynchuk, Holger R. Dullin, Konstantinos Efstathiou +1
The problem of two fixed centers was introduced by Euler as early as in 1760. It plays an important role both in celestial mechanics and in the microscopic world. In the present pa…