Macroscopic Quantum Device based on a rf SQUiD

The growing amount of theoretical interest in the area of quantum computing have stimulated in recent years research with the aim of developing a corresponding technology. Among the most promising candidates of choice appear to be superconducting Josephson systems. We present the characterization of a fully integrated Josephson device consisting of a rf-SQUID coupled to a readout system based on a dc SQUID sensor. In the classical regime we report measurements of the dc SQUID performances showing a high intrinsic responsivity and a low flux noise, giving a good signal to noise ratio in the small signal mode. Furthermore data on the decay rate from the metastable flux states of rf SQUID are reported. The low dissipation level and the good insulation of the probe from the external noise are encouraging in view of macroscopic quantum experiments. Work is in progress to improve the quality of the device and to increase its application capability towards the quantum regime.