Berlin 2005 – scientific programme

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TT: Tiefe Temperaturen

TT 14: Symposium Superconducting Quantum Systems

TT 14.1: Invited Talk

Saturday, March 5, 2005, 13:45–14:15, TU H104

Flux Qubits — •Hans Mooij — Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, The Netherlands

We investigate superconducting flux quantum bits. The qubits are fabricated of aluminum and consist of a loop with three junctions. The basic quantum states have persistent currents of opposite sign. Measurements are performed with a SQUID. Quantum operations are performed by applying microwave pulses with a frequency that is resonant with the energy splitting of the qubit. We have studied the coherence of the systems and have measured relaxation and dephasing times. The best decoherence times are of the order of 1 microsecond, while qubit operations can be performed in a few nanoseconds. We have coupled a qubit to a harmonic oscillator and we have been able to transfer a single photon. We have coupled two qubits and are able to perform conditional two-qubit operations. In the talk the general status and the latest results will be discussed.