Regensburg 2010 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 36: TR: Poster Session
TT 36.24: Poster
Donnerstag, 25. März 2010, 14:00–18:00, Poster A
Experiments with Double-SQUID Qubits — •Bernhard Dörling1, Stefano Poletto1, Maria Gabriella Castellano2, Fabio Chiarello2, and Alexey V. Ustinov1 — 1Karlsruher Institut für Technologie — 2Instituto Fotonica e Nanotecnologie - CNR, Roma, Italy
A double-SQUID qubit (flash-qubit) allows the manipulation of quantum states by very short pulses of magnetic flux, without using microwaves [1]. It consists of an rf-SQUID with a dc-SQUID replacing the single Josephson junction.
The energy potential profile is controllable by dc bias fluxes threading the two loops. The initial qubit state in a double well is prepared by applying a dc flux pulse to one loop, thereby tilting the double well so that only one of the two states remains stable. To manipulate the state of the qubit a dc flux pulse is applied to the other loop to change the potential into a single well, where coherent Larmor oscillations between the two lowest eigenstates take place. Reading out the state is once again performed in the double well situation, where our readout dc-SQUID is able to discriminate between the two computational states due to their flux difference.
We hope to present measurements done on a new sample, fabricated using shadow evaporation of aluminium and silicon nitride as the dielectric.
[1] Stefano Poletto et al., New J. Phys. 11, 013009 (2009)