High-fidelity CZ gate for the quantum Von Neumann architecture*

The building block of a scalable superconducting quantum computer has recently been demonstrated [M. Mariantoni et al., Science 334, 61 (2011)]. This architecture consists of superconducting phase qubits capacitively coupled both to individual memory resonators as well as a common bus. In this work we investigate the fidelity of a CZ logic gate between a qubit and bus in a multi-qubit device. Our results show that it is possible to implement the CZ gate with 99.99\% intrinsic fidelity in 30ns with a simple two-parameter pulse profile (plus two Z rotations). An analytical error model is also developed to explain and extend this result.