High coherence fluxonium manufactured with a wafer-scale uniformity process

Abstract

Fluxonium qubits are recognized for their high coherence times and high operation fidelities, attributed to their unique design incorporating a superinductor, which is typically implemented using an array of over 100 Josephson junctions. However, this complexity poses significant fabrication challenges, particularly in achieving high yield and junction uniformity with traditional methods. Here, we introduce an overlap process for Josephson junction fabrication that achieves nearly 100% yield and maintains uniformity across a 2-inch wafer with less than 5% variation for the phase slip junction and less than 2% for the entire junction array. We use a compact junction array design that achieves state-of-the-art dielectric loss tangents and flux noise levels, as confirmed by multiple devices. This enables fluxonium qubits to reach energy relaxation times exceeding 1 millisecond at the flux frustration point. This work paves the way for scalable high coherence fluxonium processors using CMOS-compatible processes, marking a significant step towards practical quantum computing.

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Cited by in corpus (9)

• Impact of Josephson junction array modes on fluxonium readout
• Sub-Harmonic Control of a Fluxonium Qubit via a Purcell-Protected Flux Line
• Fast microwave-driven two-qubit gates between fluxonium qubits with a transmon coupler
• Non-demolition fluorescence readout and high-fidelity unconditional reset of a fluxonium qubit via dissipation engineering
• Massive quantum superpositions using magneto-mechanics
• Entanglement dynamics and performance of two-qubit gates for superconducting qubits under non-Markovian effects
• Flux-Trapping Fluxonium Qubit
• Transmon-assisted high-fidelity controlled-Z gates for integer fluxonium qubits
• Review of Superconducting Qubit Devices and Their Large-Scale Integration