Phonon-Induced Exchange Gate Infidelities in Semiconducting Si-SiGe Spin Qubits
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arXiv
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| Hauptverfasser: | , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866929578479452160 |
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| author | Brooks, Matthew Lundgren, Rex Tahan, Charles |
| author_facet | Brooks, Matthew Lundgren, Rex Tahan, Charles |
| contents | Spin-spin exchange interactions between semiconductor spin qubits allow for fast single and two-qubit gates. During exchange, coupling of the qubits to a surrounding phonon bath may cause errors in the resulting gate. Here, the fidelities of exchange operations with semiconductor double quantum dot spin qubits in a Si-SiGe heterostructure coupled to a finite temperature phonon bath are considered. By employing a master equation approach, the isolated effect of each spin-phonon coupling term may be resolved, as well as leakage errors of encoded qubit operations. As the temperature is increased, a crossover is observed from where the primary source of error is due to a phonon induced perturbation of the two electron spin states, to one where the phonon induced coupling to an excited orbital state becomes the dominant error. Additionally, it is shown that a simple trade-off in pulse shape and length can improve robustness to spin-phonon induced errors during gate operations by up to an order of magnitude. Our results suggest that for elevated temperatures within 200-300 mK, exchange gate operations are not currently limited by bulk phonons. This is consistent with recent experiments. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2408_02742 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Phonon-Induced Exchange Gate Infidelities in Semiconducting Si-SiGe Spin Qubits Brooks, Matthew Lundgren, Rex Tahan, Charles Mesoscale and Nanoscale Physics Other Condensed Matter Quantum Physics Spin-spin exchange interactions between semiconductor spin qubits allow for fast single and two-qubit gates. During exchange, coupling of the qubits to a surrounding phonon bath may cause errors in the resulting gate. Here, the fidelities of exchange operations with semiconductor double quantum dot spin qubits in a Si-SiGe heterostructure coupled to a finite temperature phonon bath are considered. By employing a master equation approach, the isolated effect of each spin-phonon coupling term may be resolved, as well as leakage errors of encoded qubit operations. As the temperature is increased, a crossover is observed from where the primary source of error is due to a phonon induced perturbation of the two electron spin states, to one where the phonon induced coupling to an excited orbital state becomes the dominant error. Additionally, it is shown that a simple trade-off in pulse shape and length can improve robustness to spin-phonon induced errors during gate operations by up to an order of magnitude. Our results suggest that for elevated temperatures within 200-300 mK, exchange gate operations are not currently limited by bulk phonons. This is consistent with recent experiments. |
| title | Phonon-Induced Exchange Gate Infidelities in Semiconducting Si-SiGe Spin Qubits |
| topic | Mesoscale and Nanoscale Physics Other Condensed Matter Quantum Physics |
| url | https://arxiv.org/abs/2408.02742 |