Measurements for an experiment of macroscopic quantum coherence with SQUIDs

We have realized a fully integrated chip containing all the different devices (realized with trilayer Nb/AlOx/Nb technology) necessary to perform the MQC measurements. On the chip we have a double rf-SQUID inductively coupled to two different dc-SQUIDs: a standard dc-SQUID amplifier to monitor the state of the rf-SQUID, and an underdamped dc-SQUID, operating as a two-state system, to perform stroboscopic measurements of the rf-SQUID flux states. On this system we have realized a set of measurements to characterize the different devices at temperatures of the order of tens of mK. We have also performed the first measurements with the dc-SQUID amplifier and with the dc-SQUID switch, making stroboscopic measurements on the rf-SQUID.