Regensburg 2010 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 4: CE: Quantum Impurities, Kondo Physics
TT 4.5: Vortrag
Montag, 22. März 2010, 11:30–11:45, H21
The Kondo exciton: a quantum quench towards strong spin-reservoir correlations — Hakan E. Türeci1, •Markus Hanl2, Martin Claassen1, Andreas Weichselbaum2, Theresa Hecht2, Bernd Braunecker3, Alexander Govorov4, Leonid Glazman5, Jan von Delft2, and Atac Imamoglu1 — 1ETH-Zürich — 2Ludwig-Maximilians-Universität München — 3University of Basel — 4Ohio University — 5Yale University
We consider a semiconductor quantum dot coupled to a Fermionic reservoir, and study the dynamics after a quantum quench induced by the sudden creation of an exciton via optical absorption of an incident photon of definite frequency [1]. The subsequent emergence of correlations between the spin degrees of freedom of the dot and reservoir, ultimately leading to the Kondo effect, can be probed via a simple optical absorption experiment. The resulting lineshape is found to unveil three very different dynamical regimes, corresponding to short, intermediate and long times after the initial excitation, which are in turn described by the three fixed points of the single-impurity Anderson Hamiltonian. At low temperatures and just beyond the absorption threshold, the lineshape is dominated by a power-law singularity, with an exponent that is a universal function of magnetic field and gate voltage. Analytical results obtained by fixed-point perturbation theory are in excellent agreement with numerical renormalization group results.
[1] arXiv:0907.3854v1 [cond-mat.str-el]