INSTITUTE OF APPLIED PHYSICS - ACP scientists Szameit and Nolte publish in Nature Communications
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ACP scientists Szameit and Nolte publish in Nature Communications


Together with Demetri Christodoulides from CREOL, Orlande, the ACP principal scientists Szameit and Nolte have just published an original research article on "Mobility transition from ballistic to diffuse transport in non-Hermitian lattices" (Nature Comm. 4, 2533 (2013).

Abstract: Within all physical disciplines, it is accepted that wave transport is predetermined by the existence of disorder. In this vein, it is known that ballistic transport is possible only when a structure is ordered, and that disorder is crucial for diffusion or (Anderson-)localization to occur. As this commonly accepted picture is based on the very foundations of quantum mechanics where Hermiticity of the Hamiltonian is naturally assumed, the question arises whether these concepts of transport hold true within the more general context of non-Hermitian systems. Here we demonstrate theoretically and experimentally that in ordered time-independent -symmetric systems, which are symmetric under space-time reflection, wave transport can undergo a sudden change from ballistic to diffusive after a specific point in time. This transition as well as the diffusive transport in general is impossible in Hermitian systems in the absence of disorder. In contrast, we find that this transition depends only on the degree of dissipation.

Experimental realization of dissipative PT-symmetric lattices.
(a) Sketch of the fabricated waveguide arrays, where every second waveguide is sinusoidally modulated to obtain strong and controllable radiation losses. (b) Microscope image from the front facet of a sample.

>> link to the article

News from: 01.10.2013
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