Regensburg 2010 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 36: TR: Poster Session

TT 36.32: Poster

Thursday, March 25, 2010, 14:00–18:00, Poster A

Multiplexing Qubit Readout using Microwave Resonators — •Markus Jerger, Stefano Poletto, and Alexey V. Ustinov — Physikalisches Institut, Karlsruher Institut für Technologie (KIT), Wolfgang-Gaede-Str. 1, 76131 Karlsruhe, Germany

We investigate the coupling of quantum bits to transmission line resonators. A set of resonators around 10 GHz with short decay times is used for a fast measurement of the qubit states. Distinct resonances enable frequency-domain multiplexing readout of several qubits. An additional resonator with a long decay time is used to entangle the states of selected qubits and transfer information between them. We explore situations where the coupling is dominated by either the magnetic or the electric fields of the resonators.

The qubit we use is a Josephson phase qubit, consisting of a superconducting loop interrupted by a Josephson junction with a well-defined phase difference across the junction. Under certain conditions, the loop forms a two-level system with eigenfrequencies in the gigahertz range that evolves according to the laws of quantum mechanics.

In this session we will present our latest measurements.