Berlin 2012 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 1: Correlated Electrons: Low-dimensional Systems - Models 1
TT 1.14: Vortrag
Montag, 26. März 2012, 13:00–13:15, H 0104
(De)coherence in two-electron quantum dots — •Sebastian Schröter1, Paul-Antoine Hervieux2, Giovanni Manfredi2, Johannes Eiglsperger3, Moritz Schönwetter1,4, and Javier Madroñero1 — 1TU München — 2CNRS, IPCMS Strasbourg — 3Universität Regensburg — 4MPI PKS, Dresden
The coherence of a system can be evaluated by the quantum fidelity (QF). Investigations of many-body systems, based on a mean-field approach, have shown an unusual behaviour [1] of the QF decay. As an exactly treatable model, which exhibits all relevant features of the investigated many-body systems, we study a planar two-electron quantum dot with an anharmonic confining potential. It becomes apparent, that the behaviour of the QF strongly depends on the level distribution and the degree of mixing of the states, a property, which is closely connected to the chaoticity of the underlying classical analogue. For simple linear combinations of eigenstates the QF decay can be computed from static properties of the system, while for complex wave packets sophisticated numerical algorithms for the propagation of the time-dependent Schrödinger equation [2,3] are needed. We compare analytical and numerical results and address the question if the unusual behaviour gives physical insight into the decoherence of a strongly interacting system or if it is merely an artefact of the mean-field approximation.
[1] G. Manfredi, P.-A. Hervieux, New J. Phys. 11 (2009), 013050. – PRL 100 (2008), 050405. – PRL 97 (2006), 190404.
[2] J. Madroñero, B. Piraux, Phys. Rev. A 80 (2009), 033409.
[3] A. Hamido, et al., Phys. Rev. A 84 (2011), 013422.