High-fidelity gates in a Josephson qubit

Abstract

We demonstrate new experimental procedures for measuring small errors in a superconducting quantum bit (qubit). By carefully separating out gate and measurement errors, we construct a complete error budget and demonstrate single qubit gate fidelities of 0.98, limited by energy relaxation. We also introduce a new metrology tool -- a Ramsey interference error filter -- that can measure the occupation probability of the state $|2⟩$ down to $10^{-4}$, a magnitude near the fault tolerant threshold.

5 pages. 5 figures. Submitted to Physical Review Letters

References in corpus (3)

• Coupling Superconducting Qubits via a Cavity Bus
• Coherent quantum state storage and transfer between two phase qubits via a resonant cavity
• Approaching Unit Visibility for Control of a Superconducting Qubit with Dispersive Readout

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• Entanglement of superconducting qubits via microwave fields: classical and quantum regimes
• Optimal control of a leaking qubit
• Time-optimal performance of Josephson charge qubits: A process tomography approach