Building Blocks of a Flip-Chip Integrated Superconducting Quantum Processor

Abstract

We have integrated single and coupled superconducting transmon qubits into flip-chip modules. Each module consists of two chips -- one quantum chip and one control chip -- that are bump-bonded together. We demonstrate time-averaged coherence times exceeding $90\mu s$, single-qubit gate fidelities exceeding $99.9\%$, and two-qubit gate fidelities above $98.6\%$. We also present device design methods and discuss the sensitivity of device parameters to variation in interchip spacing. Notably, the additional flip-chip fabrication steps do not degrade the qubit performance compared to our baseline state-of-the-art in single-chip, planar circuits. This integration technique can be extended to the realisation of quantum processors accommodating hundreds of qubits in one module as it offers adequate input/output wiring access to all qubits and couplers.

arXiv comment33 pages, 12 figures, includes supplementary materials, updated with further calculations on participation ratio and Purcell limit

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Cited by in corpus (12)

• Scalable High-Performance Fluxonium Quantum Processor
• Transmon qubit readout fidelity at the threshold for quantum error correction without a quantum-limited amplifier
• Long-distance transmon coupler with CZ gate fidelity above $99.8\%$
• Universal fidelity reduction of quantum operations from weak dissipation
• High-coherence superconducting qubits made using industry-standard, advanced semiconductor manufacturing
• Path toward manufacturable superconducting qubits with relaxation times exceeding 0.1 ms
• Enhancing the Coherence of Superconducting Quantum Bits with Electric Fields
• Qubit-compatible substrates with superconducting through-silicon vias
• Graphical Structures for Design and Verification of Quantum Error Correction
• Flip-chip-based microwave spectroscopy of Andreev bound states in a planar Josephson junction
• Shape optimization of superconducting transmon qubit for low surface dielectric loss
• Aluminum air bridges for superconducting quantum devices realized using a single step electron-beam lithography process