High fidelity two-qubit gates on fluxoniums using a tunable coupler

Abstract

Superconducting fluxonium qubits provide a promising alternative to transmons on the path toward large-scale superconductor-based quantum computing due to their better coherence and larger anharmonicity. A major challenge for multi-qubit fluxonium devices is the experimental demonstration of a scalable crosstalk-free multi-qubit architecture with high fidelity single-qubit and two-qubit gates, single-shot readout and state initialization. Here, we present a two-qubit fluxonium-based quantum processor with a tunable coupler element following our theoretical proposal [DOI: 10.1063/5.0064800]. We experimentally demonstrate fSim-type and controlled-Z gates with $99.55\%$ and $99.23\%$ fidelities, respectively. The residual ZZ interaction is suppressed down to the few kHz level. Using a galvanically coupled flux control line, we implement high fidelity single-qubit gates and ground state initialization with a single arbitrary waveform generator channel per qubit.

18 pages, 18 figures

References in corpus (8)

• Supplementary information for "Quantum supremacy using a programmable superconducting processor"
• Charge insensitive qubit design derived from the Cooper pair box
• Strong quantum computational advantage using a superconducting quantum processor
• Simple pulses for elimination of leakage in weakly nonlinear qubits
• Controlling the spontaneous emission of a superconducting transmon qubit
• Process verification of two-qubit quantum gates by randomized benchmarking
• Quasiparticle relaxation of superconducting qubits in the presence of flux
• Fluxonium: an alternative qubit platform for high-fidelity operations

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• Generalized Toffoli gate decomposition using ququints: Towards realizing Grover's algorithm with qudits
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• High-performance multiqubit system with double-transmon couplers: Toward scalable superconducting quantum computers
• Parametrically-controlled microwave-photonic interface for the fluxonium
• Flux-pulse-assisted Readout of a Fluxonium Qubit
• Time-optimal transfer of the quantum state in long qubit arrays
• Numerical circuit synthesis and compilation for multi-state preparation
• Optimizing state transfer in a three-qubit array via quantum brachistochrone method
• Sub-Harmonic Control of a Fluxonium Qubit via a Purcell-Protected Flux Line
• Single-Qubit Gates Beyond the Rotating-Wave Approximation for Strongly Anharmonic Low-Frequency Qubits
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• Qibosoq: an open-source framework for quantum circuit RFSoC programming
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• Non-local resources for error correction in quantum LDPC codes
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• Simultaneous sweet-spot locking of gradiometric fluxonium qubits
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• Post-selection-free preparation of high-quality physical qubits
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• Parity Cross-Resonance: A Multiqubit Gate
• Robust shaped pulses for arrays of superconducting or semiconductor spin qubits with fixed Ising coupling
• Control the qubit-qubit coupling with double superconducting resonators
• The perfect entangler spectrum as a tool to analyze crosstalk