Quantum Jumps between Macroscopic Quantum States of a Superconducting   Qubit Coupled to a Microscopic Two-Level System
  We report the observation of quantum jumps between macroscopic quantum states in a superconducting phase qubit coupled to the two-level systems in the Josephson tunnel junction, and all key features of quantum jumps are confirmed in the experiments. Moreover, quantum jumps can be used to calibrate such two-level systems, which are believed to be one of the main decoherence sources in Josephson devices. 
Yang Yu, Shi-Liang Zhu, Guozhu Sun, Xueda Wen, Ning Dong, Jian Chen,   Peiheng Wu, and Siyuan Han