Dresden 2009 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 44: Transport: Quantum Coherence and Quantum Information
TT 44.16: Talk
Thursday, March 26, 2009, 18:30–18:45, HSZ 304
Losses in Microwave Resonators at Millikelvin Temperatures — •Pascal Macha1, Simon H.W. van der Ploeg1, Stefan Wünsch2, Gregor Oelsner1, Evgeni Il'ichev1, Hans-Georg Meyer1, and Michael Siegel2 — 1Institute of Photonic Technology, PO Box 100239, D-07702 Jena, Germany — 2Universität Karlsruhe, Institut für Mikro-- und Nanoelektronische Systeme, Hertzstraße 16, D-76187 Karlsruhe, Germany
We investigate the behaviour of a high-frequency coplanar waveguide resonator for low intensities of microwave power at low temperatures (20--700mK). In addition to the shift of the resonance frequency, we found a significant increase of losses in the resonator below 300mK. The temperature dependence correlates well with the expectation for a population of two level systems around the resonance frequency. Such two level systems have been identified as a major reason for decoherence in solid state quantum systems. We suggest that the increase of losses in our resonator is due to the coupling to such two level systems. In order to clarify the origin of the two level systems further investigations are necessary. This work is of great importance for the implementation of circuit QED and for detectors.