Unfolding of higher order exceptional points in a PT-symmetric Bose-Hubbard model

Graefe, Eva-Maria; Günther, Uwe; Korsch, Hans-Jürgen; Niederle, Astrid

Unfolding of higher order exceptional points in a PT-symmetric Bose-Hubbard model

Graefe, E.-M.; Günther, U.; Korsch, H.-J.; Niederle, A.

The physics of the PT-symmetric two-mode Bose-Hubbard model is discussed in detail. Special emphasis is laid on the unfolding of higher-order exceptional points (EPs) and on a detailed presentation of the Newton polygon technique. It is shown that the latter can be considered as a highly efficient tool for the unfolding analysis of higher-order roots in any polynomial equation.

Keywords: PT-symmetric quantum mechanics; Bose-Enstein condensate; Bose-Hubbard model; spectral singularity; exceptional point; Newton polygon technique; Puiseux-Newton technique; higher-order polynomial equation

Invited lecture (Conferences)
Quantum Physics with Non-Hermitian Operators (PHHQP VII), 29.06.-11.07.2008, Benasque, Spain

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