Fast Tunable Coupler for Superconducting Qubits
Radoslaw C. Bialczak, M. Ansmann, M. Hofheinz, M. Lenander, Erik A. Lucero, M. Neeley, A. D. O’Connell, D. Sank, H. Wang, Martin P. Weides, J. Wenner, Tsuyoshi Yamamoto, Andrew N. Cleland, John M. Martinis · Physical Review Letters · 2011
A major challenge in the field of quantum computing is the construction of scalable qubit coupling architectures. Here, we demonstrate a novel tunable coupling circuit that allows superconducting qubits to be coupled over long distances. We show that the interqubit coupling strength can be arbitrarily tuned over nanosecond time scales within a sequence that mimics actual use in an algorithm. The coupler has a measured on/off ratio of 1000. The design is self-contained and physically separate from the qubits, allowing the coupler to be used as a module to connect a variety of elements such as qubits, resonators, amplifiers, and readout circuitry over distances much larger than nearest-neighbor. Such design flexibility is likely to be useful for a scalable quantum computer.