Dresden 2014 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 30: Superconductivity - Poster Session
TT 30.57: Poster
Monday, March 31, 2014, 15:00–19:00, P2
Towards tunable transmon chains with individual on-chip bias — •Peter Fehlner, Jochen Braumüller, Lucas Radtke, Saskia Meißner, Hannes Rotzinger, Martin Weides, and Alexey Ustinov — KIT, Karlsruhe, Germany
Superconducting qubits constitute the main building blocks for quantum circuits. In this work we study a multi-qubit architecture [1] consisting of transmon qubits [2].
Such multi-partite quantum systems composed of harmonic and anharmonic resonant circuits manipulate the propagation of electromagnetic waves on a single photon level. These qubits operate at a Josephson to charging energy ratio of a few hundred to preserve sufficient anharmonicity. We employ a coplanar waveguide geometry based on interdigitated finger capacitors containing two Josephson junctions in parallel for each qubit. The sputter-deposited overlap Al-AlOx-Al tunnel junctions are e-beam lithographically patterned for junction ares of about 0.1 µ m2. The transmons are capacitively coupled to a half wavelength transmission line resonator. The on-chip bias lines provide individual σz control of each qubit in the chain. Resonator readout and global σx, σy qubit manipulation is mediated by the resonator coupled to the feedline.
We will present sample design, microwave simulations and first results measured at cryogenic temperatures.