Regensburg 2007 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 28: Transport - Poster Session

TT 28.27: Poster

Thursday, March 29, 2007, 14:00–17:45, Poster A

Design, fabrication and characterization of microwave resonators for circuit Quantum Electrodynamics — •Susanne Hofmann, Thomas Niemczyk, Mattes Mariantoni, Achim Marx, and Rudolf Gross — Walther-Meissner-Institut für Tieftemperaturforschung, Bayerischen Akademie der Wissenschaften, Walther-Meissner Str. 8, 85748 Garching, Germany

A central issue in quantum information processing is the coupling of quantum bits (qubits) to a suitable readout system. In 2004 Wallraff et al. realized the strong coupling of microwave photons in a coplanar waveguide resonator to a superconducting (sc) charge qubit. To achieve strong coupling between the microwave field and the charge qubit, it is placed at the maximum of the electric field in the resonator. Furthermore, the resonator needs a high quality factor which can be achieved for sc resonators coupled weakly to the environment. With a single photon in the cavity, vacuum rabi splitting in the resonator - qubit system can be observed. We have designed and fabricated sc resonators that are designed for coupling with sc flux qubits. Flux qubits couple to the magnetic field mode of the field in the resonator. The length of the resonators is designed to be half a wavelength in order to achieve maximum coupling in the middle of the resonators. This results in short resonators without the need for a meandering geometry. Various designs with different geometries and coupling to the environment have been fabricated from niobium on silicon and sapphire substrates.

This work is supported by the DFG via SFB 631.