Modular quantum processor with an all-to-all reconfigurable router

Abstract

Superconducting qubits provide a promising approach to large-scale fault-tolerant quantum computing. However, qubit connectivity on a planar surface is typically restricted to only a few neighboring qubits. Achieving longer-range and more flexible connectivity, which is particularly appealing in light of recent developments in error-correcting codes, however usually involves complex multi-layer packaging and external cabling, which is resource-intensive and can impose fidelity limitations. Here, we propose and realize a high-speed on-chip quantum processor that supports reconfigurable all-to-all coupling with a large on-off ratio. We implement the design in a four-node quantum processor, built with a modular design comprising a wiring substrate coupled to two separate qubit-bearing substrates, each including two single-qubit nodes. We use this device to demonstrate reconfigurable controlled-Z gates across all qubit pairs, with a benchmarked average fidelity of $96.00\%\pm 0.08\%$ and best fidelity of $97.14\%\pm 0.07\%$, limited mainly by dephasing in the qubits. We also generate multi-qubit entanglement, distributed across the separate modules, demonstrating GHZ-3 and GHZ-4 states with fidelities of $88.15\%\pm 0.24\%$ and $75.18\%\pm 0.11\%$, respectively. This approach promises efficient scaling to larger-scale quantum circuits, and offers a pathway for implementing quantum algorithms and error correction schemes that benefit from enhanced qubit connectivity.

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Cited by in corpus (14)

• Teleportation and Entanglement Swapping of Continuous Quantum Variables of Microwave Radiation
• Accelerating multipartite entanglement generation in non-Hermitian superconducting qubits
• Realization of Constant-Depth Fan-Out with Real-Time Feedforward on a Superconducting Quantum Processor
• Quantum error detection in qubit-resonator star architecture
• Resource-Efficient Cross-Platform Verification with Modular Superconducting Devices
• Flexible Readout and Unconditional Reset for Superconducting Multi-Qubit Processors with Tunable Purcell Filters
• Mitigating cosmic ray-like correlated events with a modular quantum processor
• High-fidelity multipartite entanglement creation in non-Hermitian qubits
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• Distilled remote entanglement between superconducting qubits across optical channels
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