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| Main Authors: | , |
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| Format: | Preprint |
| Published: |
2024
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2404.10983 |
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| _version_ | 1866917642349051904 |
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| author | Ohfuchi, Mari Sato, Shintaro |
| author_facet | Ohfuchi, Mari Sato, Shintaro |
| contents | High-fidelity quantum state transfer and remote entanglement between superconducting fixed-frequency qubits have not yet been realized. In this study, we propose an alternative remote cross-resonance gate. Considering multiple modes of a superconducting coaxial cable connecting qubits, we must find conditions under which the cross-resonance gate operates with a certain accuracy even in the presence of qubit frequency shifts due to manufacturing errors. For 0.25- and 0.5-m cables, remote cross-resonance gates with a concurrence of $>99.9\%$ in entanglement generation are obtained even with $\pm$10-MHz frequency shifts. For a 1-m cable with a narrow mode spacing, a concurrence of 99.5\% is achieved by reducing the coupling between the qubits and cable. The optimized echoed raised-cosine pulse duration is 150--400 ns, which is similar to the operation time of cross-resonance gates between neighboring qubits on a chip. The dissipation through the cable modes does not considerably affect the obtained results. Such high-precision quantum interconnects pave the way not only for scaling up quantum computer systems but also for nonlocal connections on a chip. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2404_10983 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Remote Cross-resonance Gate between Superconducting Fixed-frequency Qubits Ohfuchi, Mari Sato, Shintaro Quantum Physics High-fidelity quantum state transfer and remote entanglement between superconducting fixed-frequency qubits have not yet been realized. In this study, we propose an alternative remote cross-resonance gate. Considering multiple modes of a superconducting coaxial cable connecting qubits, we must find conditions under which the cross-resonance gate operates with a certain accuracy even in the presence of qubit frequency shifts due to manufacturing errors. For 0.25- and 0.5-m cables, remote cross-resonance gates with a concurrence of $>99.9\%$ in entanglement generation are obtained even with $\pm$10-MHz frequency shifts. For a 1-m cable with a narrow mode spacing, a concurrence of 99.5\% is achieved by reducing the coupling between the qubits and cable. The optimized echoed raised-cosine pulse duration is 150--400 ns, which is similar to the operation time of cross-resonance gates between neighboring qubits on a chip. The dissipation through the cable modes does not considerably affect the obtained results. Such high-precision quantum interconnects pave the way not only for scaling up quantum computer systems but also for nonlocal connections on a chip. |
| title | Remote Cross-resonance Gate between Superconducting Fixed-frequency Qubits |
| topic | Quantum Physics |
| url | https://arxiv.org/abs/2404.10983 |