Dresden 2003 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 20: Postersitzung IV (Mesoskopische Systeme, Supraleitung: Massivmaterialien, Bandleiter, Pinning, Vortexdynamik, Transporteigenschaften, Korngrenzen)

TT 20.24: Poster

Donnerstag, 27. März 2003, 14:30–19:00, P2c, P2d

Andreev Entangler: creation of mobile spin-entangled electrons — •Patrik Recher, Eugene V. Sukhorukov, and Daniel Loss — Department of Physics and Astronomy, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland

We propose solid state electron entanglers which create spatially separated and mobile spin-entangled electrons as needed for quantum communication and computation schemes. We show that the entanglement present in superconductors (SC) in terms of the Cooper pairs (spin-singlet) can be extracted to normal leeds via a coherent two-particle tunneling event (Andreev tunneling). The Coulomb interaction between the two spin-entangled electrons can be exploited to spatially separate them so that the residual current from the SC to the leads is carried by pair-split processes where two electrons enter different leads. For that purpose we propose to have intermediate quantum dots weakly coupled to the SC and subsequently to Fermi liquid leads. Alternatively, the SC can be tunnel-coupled to two quantum wires which show Luttinger liquid behavior. There exists a parameter regime where the initial entanglement of a Cooper pair is preserved during the transport to the leads. It is shown that such entanglers are efficient for realistic parameters.