Dresden 2011 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 34: TR: Quantum Coherence and Quantum Information Systems 2 (jointly with MA and HL)

TT 34.16: Vortrag

Mittwoch, 16. März 2011, 18:30–18:45, HSZ 03

Turning a vice into a virtue: Hyperfine induced nuclear spin dynamics in double quantum dots — •Bjoern Erbe and John Schliemann — Department of Physics, University of Regensburg, 93040 Regensburg, Germany

Electron spins confined in semiconductor quantum dots with an s-type conduction band, like for example GaAs quantum dots, interact with the surrounding nuclear spins via the hyperfine interaction [1]. With respect to possible future solid state quantum computation systems utilizing the electron spin as the qubit [2], these interactions act as a source of decoherence. We demonstrate that it is possible to turn vice into virtue by using the hyperfine interaction in order to utilize nuclear baths for quantum information purposes [3].

To this end, we numerically study the hyperfine induced nuclear spin dynamics in a system of two coupled quantum dots in zero magnetic field. Each of the electron spins is considered to interact with an individual bath of nuclear spins. Through quantitative investigations of several scaling behaviors we show that it is possible to swap the nuclear ensembles and indicate that it might even be possible to fully entangle them. It turns out that the larger the baths are, the more relevant they become as a ressource of quantum information.
see e.g. J. Schliemann, A. Khaetskii, and D. Loss, J. Phys.: Condens. Matter 15, R1809 (2003).
D. Loss and D. P. DiVincenzo, Phys. Rev. A 57, 120 (1998).
B. Erbe and J. Schliemann, in preparation