Residual-$ZZ$-coupling suppression and fast two-qubit gate for Kerr-cat qubits based on level-degeneracy engineering
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| Main Authors: | , , , |
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| Format: | Preprint |
| Published: |
2024
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| _version_ | 1866909469784408064 |
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| author | Aoki, Takaaki Tomonaga, Akiyoshi Mizuno, Kosuke Masuda, Shumpei |
| author_facet | Aoki, Takaaki Tomonaga, Akiyoshi Mizuno, Kosuke Masuda, Shumpei |
| contents | Building large-scale quantum computers requires an interqubit-coupling scheme with a high on-off ratio to avoid unwanted crosstalk coming from residual coupling and to enable fast multi-qubit operations. We propose a $ZZ$-coupling scheme for two Kerr-cat qubits with a frequency-tunable coupler. By making four relevant states of the two Kerr-cat qubits quadruply degenerate, we can switch off the $ZZ$ coupling. By partially lifting the level degeneracy, we can switch it on. We theoretically show that an experimentally feasible circuit model suppresses the residual $ZZ$ coupling. Moreover, our circuit can realize $R_{ZZ}(-π/2)$-gate fidelity higher than $99.9\%$ within $18$ ns when decoherence is ignored. Our model includes the first-order terms in expansion beyond the rotating-wave approximation. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2410_00431 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Residual-$ZZ$-coupling suppression and fast two-qubit gate for Kerr-cat qubits based on level-degeneracy engineering Aoki, Takaaki Tomonaga, Akiyoshi Mizuno, Kosuke Masuda, Shumpei Quantum Physics Building large-scale quantum computers requires an interqubit-coupling scheme with a high on-off ratio to avoid unwanted crosstalk coming from residual coupling and to enable fast multi-qubit operations. We propose a $ZZ$-coupling scheme for two Kerr-cat qubits with a frequency-tunable coupler. By making four relevant states of the two Kerr-cat qubits quadruply degenerate, we can switch off the $ZZ$ coupling. By partially lifting the level degeneracy, we can switch it on. We theoretically show that an experimentally feasible circuit model suppresses the residual $ZZ$ coupling. Moreover, our circuit can realize $R_{ZZ}(-π/2)$-gate fidelity higher than $99.9\%$ within $18$ ns when decoherence is ignored. Our model includes the first-order terms in expansion beyond the rotating-wave approximation. |
| title | Residual-$ZZ$-coupling suppression and fast two-qubit gate for Kerr-cat qubits based on level-degeneracy engineering |
| topic | Quantum Physics |
| url | https://arxiv.org/abs/2410.00431 |