QUROPE Quantum Information Processing and Communication in Europe

Superconducting qubits shine out among other qubit implementations with respect to their excellent scalability. In collaboration with the group of E. Ilichev at IPHT in Jena, the Karlsruhe experimental group of A. Ustinov has performed experiments on a chip containing 7 flux qubits. A newly developed measurement scheme based on frequency multiplexing allowed the researchers to read out all qubits simultaneously, using only a single signal cable. Via the same transmission line, the qubits were successfully operated in the coherent regime and synchronously addressed via synthesized multi-tone signals. Calculations of the expected crosstalk indicate that this scheme should be scalable up to 100 qubits per GHZ bandwidth.

M. Jerger, S. Poletto, P. Macha, U. Hübner, A. Lukashenko, E. Il'ichev and A. V. Ustinov, Europhys. Lett. 96, 40012 (2011)