TY - JOUR KW - pfc AU - Joseph Kerckhoff AU - Konrad Lehnert BT - Physical Review Letters DA - 2012-10 DO - 10.1103/PhysRevLett.109.153602 PY - 2012 EP - 153602 T2 - Physical Review Letters TI - Superconducting Microwave Multivibrator Produced by Coherent Feedback VL - 109 SN - 0031-9007 ER -