Tunable Inductive Coupler for High-Fidelity Gates Between Fluxonium Qubits
The fluxonium qubit is a promising candidate for quantum computation due to its long coherence times and large anharmonicity. We present a tunable coupler that realizes strong inductive coupling between two heavy-fluxonium qubits, each with approximately 50-MHz frequencies and approximately 5-GHz an...
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| Format: | Article |
| Language: | English |
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American Physical Society
2024-05-01
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| Series: | PRX Quantum |
| Online Access: | http://doi.org/10.1103/PRXQuantum.5.020326 |
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| author | Helin Zhang Chunyang Ding D.K. Weiss Ziwen Huang Yuwei Ma Charles Guinn Sara Sussman Sai Pavan Chitta Danyang Chen Andrew A. Houck Jens Koch David I. Schuster |
| author_facet | Helin Zhang Chunyang Ding D.K. Weiss Ziwen Huang Yuwei Ma Charles Guinn Sara Sussman Sai Pavan Chitta Danyang Chen Andrew A. Houck Jens Koch David I. Schuster |
| author_sort | Helin Zhang |
| collection | DOAJ |
| description | The fluxonium qubit is a promising candidate for quantum computation due to its long coherence times and large anharmonicity. We present a tunable coupler that realizes strong inductive coupling between two heavy-fluxonium qubits, each with approximately 50-MHz frequencies and approximately 5-GHz anharmonicities. The coupler enables the qubits to have a large tuning range of XX coupling strengths (−35 to 75 MHz). The ZZ coupling strength is <3 kHz across the entire coupler bias range and <100 Hz at the coupler off position. These qualities lead to fast high-fidelity single- and two-qubit gates. By driving at the difference frequency of the two qubits, we realize a sqrt[iSWAP] gate in 258 ns with fidelity 99.72%, and by driving at the sum frequency of the two qubits, we achieve a sqrt[bSWAP] gate in 102 ns with fidelity 99.91%. This latter gate is only five qubit Larmor periods in length. We run cross-entropy benchmarking for over 20 consecutive hours and measure stable gate fidelities, with sqrt[bSWAP] drift (2σ) <0.02% and sqrt[iSWAP] drift <0.08%. |
| format | Article |
| id | doaj-art-d2adfd68d1004fada369af6cc8ce676c |
| institution | DOAJ |
| issn | 2691-3399 |
| language | English |
| publishDate | 2024-05-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | PRX Quantum |
| spelling | doaj-art-d2adfd68d1004fada369af6cc8ce676c2025-08-20T02:57:51ZengAmerican Physical SocietyPRX Quantum2691-33992024-05-015202032610.1103/PRXQuantum.5.020326Tunable Inductive Coupler for High-Fidelity Gates Between Fluxonium QubitsHelin ZhangChunyang DingD.K. WeissZiwen HuangYuwei MaCharles GuinnSara SussmanSai Pavan ChittaDanyang ChenAndrew A. HouckJens KochDavid I. SchusterThe fluxonium qubit is a promising candidate for quantum computation due to its long coherence times and large anharmonicity. We present a tunable coupler that realizes strong inductive coupling between two heavy-fluxonium qubits, each with approximately 50-MHz frequencies and approximately 5-GHz anharmonicities. The coupler enables the qubits to have a large tuning range of XX coupling strengths (−35 to 75 MHz). The ZZ coupling strength is <3 kHz across the entire coupler bias range and <100 Hz at the coupler off position. These qualities lead to fast high-fidelity single- and two-qubit gates. By driving at the difference frequency of the two qubits, we realize a sqrt[iSWAP] gate in 258 ns with fidelity 99.72%, and by driving at the sum frequency of the two qubits, we achieve a sqrt[bSWAP] gate in 102 ns with fidelity 99.91%. This latter gate is only five qubit Larmor periods in length. We run cross-entropy benchmarking for over 20 consecutive hours and measure stable gate fidelities, with sqrt[bSWAP] drift (2σ) <0.02% and sqrt[iSWAP] drift <0.08%.http://doi.org/10.1103/PRXQuantum.5.020326 |
| spellingShingle | Helin Zhang Chunyang Ding D.K. Weiss Ziwen Huang Yuwei Ma Charles Guinn Sara Sussman Sai Pavan Chitta Danyang Chen Andrew A. Houck Jens Koch David I. Schuster Tunable Inductive Coupler for High-Fidelity Gates Between Fluxonium Qubits PRX Quantum |
| title | Tunable Inductive Coupler for High-Fidelity Gates Between Fluxonium Qubits |
| title_full | Tunable Inductive Coupler for High-Fidelity Gates Between Fluxonium Qubits |
| title_fullStr | Tunable Inductive Coupler for High-Fidelity Gates Between Fluxonium Qubits |
| title_full_unstemmed | Tunable Inductive Coupler for High-Fidelity Gates Between Fluxonium Qubits |
| title_short | Tunable Inductive Coupler for High-Fidelity Gates Between Fluxonium Qubits |
| title_sort | tunable inductive coupler for high fidelity gates between fluxonium qubits |
| url | http://doi.org/10.1103/PRXQuantum.5.020326 |
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