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TT: Fachverband Tiefe Temperaturen
TT 23: TR: Quantum Coherence and Quantum Information Systems 2
TT 23.4: Hauptvortrag
Mittwoch, 24. März 2010, 14:45–15:15, H18
Superconducting Flux Qubits in Circuit QED and Detection of Weak Microwave Signals — •Achim Marx1, Alex Baust1, Elisabeth Hoffmann1, Matteo Mariantoni1, Edwin P. Menzel1, Thomas Niemczyk1, Manuel Schwarz1, Thomas Weissl1, Enrique Solano2, Juan J. Garcia-Ripoll3, Frank Deppe1, Hans Hübl1, and Rudolf Gross1 — 1Walther-Meissner-Institut and TU München, Germany — 2Universidad del País Vasco and Ikerbasque Foundation, Bilbao, Spain — 3Instituto de Fisica Fundamental, CSIC, Madrid, Spain
Superconducting qubits behave as artificial two-level atoms. Coupling them to on-chip microwave resonators has given rise to the field of circuit quantum electrodynamics, where fundamental quantum properties can be investigated. Here, we present spectroscopy data on single and two flux qubits coupled to a coplanar transmission line resonator. The strong coupling regime can be readily accessed both for inductive and galvanic coupling. The inherent tunability of the artificial atoms allows to control the symmetry properties of the coupled qubit-resonator system. Systems consisting of several resonators, which can be coupled by using superconducting qubits can be used to generate quantum microwave signals. To detect such weak microwave signals on a single photon level we have developed a signal recovery method based on a cross-correlation technique. This method has been successfully applied to analyze thermal microwave states and propagating signals on a single photon level. We acknowledge support from SFB 631, NIM, UPV/EHU Grant GIU07/40 and European project EuroSQIP.