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.

References in corpus (22)

• Charge insensitive qubit design derived from the Cooper pair box
• Dynamical decoupling and noise spectroscopy with a superconducting flux qubit
• Decoherence of flux qubits due to 1/f flux noise
• Decoherence benchmarking of superconducting qubits
• Fluxonium: an alternative qubit platform for high-fidelity operations
• Suppressing relaxation in superconducting qubits by quasiparticle pumping
• Non-Poissonian Quantum Jumps of a Fluxonium Qubit due to Quasiparticle Excitations
• High-Fidelity, Frequency-Flexible Two-Qubit Fluxonium Gates with a Transmon Coupler
• High fidelity two-qubit gates on fluxoniums using a tunable coupler
• Scalable High-Performance Fluxonium Quantum Processor
• Geometrical dependence of low frequency noise in superconducting flux qubits
• Overlap junctions for high coherence superconducting qubits
• Path toward manufacturable superconducting qubits with relaxation times exceeding 0.1 ms
• Precision measurement of the microwave dielectric loss of sapphire in the quantum regime with parts-per-billion sensitivity
• Two-level system hyperpolarization using a quantum Szilard engine
• Fast high-fidelity gates for galvanically-coupled fluxonium qubits using strong flux modulation
• Coherent superconducting qubits from a subtractive junction fabrication process
• Coupler microwave-activated controlled phase gate on fluxonium qubits
• CNOT gates for fluxonium qubits via selective darkening of transitions
• Wafer-scale uniformity of Dolan-bridge and bridgeless Manhattan-style Josephson junctions for superconducting quantum processors
• Native approach to controlled-Z gates in inductively coupled fluxonium qubits
• Efficient initialization of fluxonium qubits based on auxiliary energy levels

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