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Q: Fachverband Quantenoptik und Photonik

Q 18: Quantum Gases (Bosons) II

Q 18.8: Vortrag

Montag, 5. März 2018, 15:45–16:00, K 2.020

Excitation transport in networks with an energy gradient, modelled after photosynthetic systems — Hlér Kristjánsson^1,2, Jonathan Brugger¹, Gabriel Dufour¹, •Christian Scheppach¹, and Andreas Buchleitner¹ — ¹Physikalisches Institut, Albert-Ludwigs-Universität Freiburg i. Br., Germany — ²Department of Physics, Imperial College London, U.K.

In photosynthesis, a photon is absorbed by a light-harvesting antenna, and the energy excitation is transported along several chlorophylls to a reaction centre. Recently, there has been much discussion whether a quantum mechanically coherent description of the transport process is necessary to understand it. This motivates our theoretical study of excitation transport through networks of two-level systems. To account for the limited experimental knowledge of the parameters, as well as the natural variability in biological systems, we study statistical ensembles of networks and look for design principles ensuring efficient transport. When the input and output site of the network have the same energy, ``centrosymmetry'' of the Hamiltonian and a ``dominant doublet'' are design principles enhancing the probability of efficient transport. In the more realistic case of an energy difference between the input and output site, external vibrations can bridge the gap, and are treated with Floquet theory. Here, one can demand a ``dominant Floquet doublet'', and ``anticentrosymmetry'' can be imposed in the extended Floquet-Hilbert space.