Berlin 2005 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 22: Transport - Nanoelectronics II: Quantum Dots and Wires, Point Contacts
TT 22.11: Vortrag
Montag, 7. März 2005, 16:45–17:00, TU H2053
Adiabatic pumping and Berry’s phase in a mesoscopic ring — •Angelika Bender1,2, Frank W. J. Hekking2, Alexander Shnirman1, and Yuval Gefen3 — 1Institut für Theoretische Festkörperphysik, Universität Karlsruhe, D-76128 Karlsruhe, Germany — 2Laboratoire de Physique et Modélisation des Milieux Condensés, CNRS, BP 166, F-38042 Grenoble, France — 3Department of Condensed Matter Physics, The Weizmann Institut of Science, Rehovot 76100, Israel
We study parametric pumping of charge in a mesoscopic system, induced by adiabatic and periodic changes of system parameters. Adiabatic changes of a Hamiltonian lead to phases in the wavefunction. We study the physical meaning of these phases for a loop with an impurity. The loop is threaded by a magnetic flux that induces persistent currents. We compute the total charge that passes the system upon a periodic change of flux and impurity strength and show that it is directly related to the phases of the wavefunction. We find in particular the link between pumped charge and Berry’s phase. Further calculations include noise and decoherence due to the coupling of the system to its environment.