Universal fast flux control of a coherent, low-frequency qubit

Abstract

The \textit{heavy-fluxonium} circuit is a promising building block for superconducting quantum processors due to its long relaxation and dephasing time at the half-flux frustration point. However, the suppressed charge matrix elements and low transition frequency have made it challenging to perform fast single-qubit gates using standard protocols. We report on new protocols for reset, fast coherent control, and readout, that allow high-quality operation of the qubit with a 14 MHz transition frequency, an order of magnitude lower in energy than the ambient thermal energy scale. We utilize higher levels of the fluxonium to initialize the qubit with $97$\% fidelity, corresponding to cooling it to $190\mu \mathrm{K}$. We realize high-fidelity control using a universal set of single-cycle flux gates, which are comprised of directly synthesizable fast pulses, while plasmon-assisted readout is used for measurements. On a qubit with $T_1,T_{2e}\sim$~300~$\mu \mathrm{s}$, we realize single-qubit gates in $20-60$~ns with an average gate fidelity of $99.8\%$ as characterized by randomized benchmarking.

12 pages, 8 figures

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Cited by in corpus (67)

• Circuit Quantum Electrodynamics
• Fluxonium: an alternative qubit platform for high-fidelity operations
• The QICK (Quantum Instrumentation Control Kit): Readout and control for qubits and detectors
• High-Fidelity, Frequency-Flexible Two-Qubit Fluxonium Gates with a Transmon Coupler
• Moving beyond the transmon: Noise-protected superconducting quantum circuits
• Scalable High-Performance Fluxonium Quantum Processor
• Fast logic with slow qubits: microwave-activated controlled-Z gate on low-frequency fluxoniums
• Quantum non-demolition dispersive readout of a superconducting artificial atom using large photon numbers
• Calibration of flux crosstalk in large-scale flux-tunable superconducting quantum circuits
• Analytic Design of Accelerated Adiabatic Gates in Realistic Qubits: General Theory and Applications to Superconducting Circuits
• Fast high-fidelity gates for galvanically-coupled fluxonium qubits using strong flux modulation
• Geometric superinductance qubits: Controlling phase delocalization across a single Josephson junction
• Gate-tunable kinetic inductance in proximitized nanowires
• Magnifying quantum phase fluctuations with Cooper-pair pairing
• Multi-mode architectures for noise-resilient superconducting qubits
• Identification of different types of high-frequency defects in superconducting qubits
• Fast and Robust Geometric Two-Qubit Gates for Superconducting Qubits and beyond
• Coupler microwave-activated controlled phase gate on fluxonium qubits
• CNOT gates for fluxonium qubits via selective darkening of transitions
• Experimental advances with the QICK (Quantum Instrumentation Control Kit) for superconducting quantum hardware
• Native approach to controlled-Z gates in inductively coupled fluxonium qubits
• Blueprint for all-to-all connected superconducting spin qubits
• Stabilizing and improving qubit coherence by engineering noise spectrum of two-level systems
• Efficient initialization of fluxonium qubits based on auxiliary energy levels
• Quantum circuits with multiterminal Josephson-Andreev junctions
• High coherence fluxonium manufactured with a wafer-scale uniformity process
• Alternative fast quantum logic gates using nonadiabatic Landau-Zener-Stückelberg-Majorana transitions
• Fast Flux Entangling Gate for Fluxonium Circuits
• Electron shelving of a superconducting artificial atom
• Gatemonium: A Voltage-Tunable Fluxonium
• Baseband control of superconducting qubits with shared microwave drives
• High-Order Qubit Dephasing at Sweet Spots by Non-Gaussian Fluctuators: Symmetry Breaking and Floquet Protection
• Optomechanical quantum entanglement mediated by acoustic phonon fields
• Microwave-activated gates between a fluxonium and a transmon qubit
• The Floquet Fluxonium Molecule: Driving Down Dephasing in Coupled Superconducting Qubits
• Parametrically-controlled microwave-photonic interface for the fluxonium
• Dephasing in Fluxonium Qubits from Coherent Quantum Phase Slips
• Solomon equations for qubit and two-level systems: Insights into non-Poissonian quantum jumps
• Impact of Josephson junction array modes on fluxonium readout
• Hybrid cat-transmon architecture for scalable, hardware-efficient quantum error correction
• Flux-pulse-assisted Readout of a Fluxonium Qubit
• Cavity mode dephasing via the optomechanical interaction with an acoustic environment
• Tunneling of fluxons via a Josephson resonant level
• Universal pulses for superconducting qudit ladder gates
• Bound states in the continuum in a fluxonium qutrit
• The quartic Blochnium: an anharmonic quasicharge superconducting qubit
• Vantablack Shielding of Superconducting Qubit Systems
• Deterministic two-photon C-Z gate with the two-photon quantum Rabi model
• Fast microwave-driven two-qubit gates between fluxonium qubits with a transmon coupler
• Cross-resonance control of an oscillator with an auxiliary fluxonium qubit
• Viewing protected superconducting qubits through the lens of the cat qubit
• Stable time rondeau crystals in dissipative many-body systems
• Parameter optimization for the unimon qubit
• Flux-Tunable Regimes and Supersymmetry in Twisted Cuprate Heterostructures
• In-situ tunable interaction with an invertible sign between a fluxonium and a post cavity
• Loss-induced quantum nonreciprocity and entanglement in superconducting qubits
• Simulation of a rapid qubit readout dependent on the transmission of a single fluxon
• Non-demolition fluorescence readout and high-fidelity unconditional reset of a fluxonium qubit via dissipation engineering
• Tunable coupling scheme for implementing two-qubit gates on fluxonium qubits
• Simultaneous sweet-spot locking of gradiometric fluxonium qubits
• Flux-Trapping Fluxonium Qubit
• Optimization of Floquet fluxonium qubits with commensurable two-tone drives
• Characterization of multi-level dynamics and decoherence in a high-anharmonicity capacitively shunted flux circuit
• A fluxonium qubit-based hybrid electromechanical system
• Proposal for erasure conversion in integer fluxonium qubits
• A Thermally Modulated SINIS Trasconductance Amplifier
• Robust multi-mode superconducting circuit optimized for quantum information processing