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| Autores principales: | , , , , , |
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| Formato: | Preprint |
| Publicado: |
2026
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| Materias: | |
| Acceso en línea: | https://arxiv.org/abs/2603.06830 |
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| _version_ | 1866912950637297664 |
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| author | Ma, Longyu Liu, Tony Shabani, Javad Sardashti, Kasra Manucharyan, Vladimir E. Vavilov, Maxim G. |
| author_facet | Ma, Longyu Liu, Tony Shabani, Javad Sardashti, Kasra Manucharyan, Vladimir E. Vavilov, Maxim G. |
| contents | We present a theory of a flux-tunable superconducting qubit, the "Fraunhofer qubit," based on the Fraunhofer interference in a wide ballistic Josephson junction. As magnetic flux threads the junction, the Josephson potential is effectively averaged over a phase window proportional to flux. For perfectly transmitting junctions, as flux approaches one flux quantum h/2e, the flux averaging transforms the potential near its minimum from a quadratic to a triangular shape, resulting in significantly enhanced anharmonicity. This enhancement persists for junctions with lower transparency conducting channels. Microscopic tight-binding simulations that include inhomogeneous electrostatic potential and disorder confirm the enhancement of anharmonicity. These results establish a framework for flux control in hybrid superconducting circuits, providing an operating point where anharmonicity and charge-noise protection can be optimally balanced. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2603_06830 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Anharmonicity and Charge-Noise Sensitivity of Fraunhofer Qubit Ma, Longyu Liu, Tony Shabani, Javad Sardashti, Kasra Manucharyan, Vladimir E. Vavilov, Maxim G. Mesoscale and Nanoscale Physics We present a theory of a flux-tunable superconducting qubit, the "Fraunhofer qubit," based on the Fraunhofer interference in a wide ballistic Josephson junction. As magnetic flux threads the junction, the Josephson potential is effectively averaged over a phase window proportional to flux. For perfectly transmitting junctions, as flux approaches one flux quantum h/2e, the flux averaging transforms the potential near its minimum from a quadratic to a triangular shape, resulting in significantly enhanced anharmonicity. This enhancement persists for junctions with lower transparency conducting channels. Microscopic tight-binding simulations that include inhomogeneous electrostatic potential and disorder confirm the enhancement of anharmonicity. These results establish a framework for flux control in hybrid superconducting circuits, providing an operating point where anharmonicity and charge-noise protection can be optimally balanced. |
| title | Anharmonicity and Charge-Noise Sensitivity of Fraunhofer Qubit |
| topic | Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2603.06830 |