Hannover 2020 – wissenschaftliches Programm
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Q 6.4: Vortrag
Montag, 9. März 2020, 12:00–12:15, f342
Observation of Non-Hermitian Anderson Transport — •Sebastian Weidemann1, Mark Kremer1, Stefano Longhi2, and Alexander Szameit1 — 1Experimental Solid State Optics Group, Institute of Physics, University of Rostock, Germany — 2Dipartimento di Fisica, Politecnico di Milano, Piazza L. da Vinci 32, Milano I-20133, Italy
It was a major breakthrough for the understanding of conductance in solids when Anderson showed that stochastic imperfections in crystalline lattices can result in self-trapping of a single electron via quantum interference. For the underlying mechanism, called Anderson localization, disorder is described by random changes only in the real part of the potential. We take a new perspective within the study of disorderd systems by asking whether the concepts of localization and transport carry over to the more general context of open systems when random changes occur also in the imaginary part of the potential. To this end we employ light propagation in a photonic lattice with tunable dissipation as a model system. The controllable dissipation allows to realize nearly arbritrary complex potentials. Our theoretical and experimental findings reveal a novel non-Hermitian transport mechanism: The imaginary disorder not only leads to a fully localized eigenmode spectrum like in the Hermitian case, but also causes surprising transport dynamics that is characterized by ultra-far jumps and a restoration of ballistic spreading. Beyond the experimental observation of this Anderson Transport, we provide a theoretical explanation by giving the analytical solution for a corresponding chain model.