Observation of Josephson Harmonics in Tunnel Junctions
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arXiv
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| Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , , , , , , , |
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| Format: | Preprint |
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2023
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| _version_ | 1866910693759909888 |
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| author | Willsch, Dennis Rieger, Dennis Winkel, Patrick Willsch, Madita Dickel, Christian Krause, Jonas Ando, Yoichi Lescanne, Raphaël Leghtas, Zaki Bronn, Nicholas T. Deb, Pratiti Lanes, Olivia Minev, Zlatko K. Dennig, Benedikt Geisert, Simon Günzler, Simon Ihssen, Sören Paluch, Patrick Reisinger, Thomas Hanna, Roudy Bae, Jin Hee Schüffelgen, Peter Grützmacher, Detlev Buimaga-Iarinca, Luiza Morari, Cristian Wernsdorfer, Wolfgang DiVincenzo, David P. Michielsen, Kristel Catelani, Gianluigi Pop, Ioan M. |
| author_facet | Willsch, Dennis Rieger, Dennis Winkel, Patrick Willsch, Madita Dickel, Christian Krause, Jonas Ando, Yoichi Lescanne, Raphaël Leghtas, Zaki Bronn, Nicholas T. Deb, Pratiti Lanes, Olivia Minev, Zlatko K. Dennig, Benedikt Geisert, Simon Günzler, Simon Ihssen, Sören Paluch, Patrick Reisinger, Thomas Hanna, Roudy Bae, Jin Hee Schüffelgen, Peter Grützmacher, Detlev Buimaga-Iarinca, Luiza Morari, Cristian Wernsdorfer, Wolfgang DiVincenzo, David P. Michielsen, Kristel Catelani, Gianluigi Pop, Ioan M. |
| contents | Approaches to developing large-scale superconducting quantum processors must cope with the numerous microscopic degrees of freedom that are ubiquitous in solid-state devices. State-of-the-art superconducting qubits employ aluminum oxide (AlO$_x$) tunnel Josephson junctions as the sources of nonlinearity necessary to perform quantum operations. Analyses of these junctions typically assume an idealized, purely sinusoidal current-phase relation. However, this relation is only expected to hold in the limit of vanishingly low-transparency channels in the AlO$_x$ barrier. Here we show that the standard current-phase relation fails to accurately describe the energy spectra of transmon artificial atoms across various samples and laboratories. Instead, a mesoscopic model of tunneling through an inhomogeneous AlO$_x$ barrier predicts percent-level contributions from higher Josephson harmonics. By including these in the transmon Hamiltonian, we obtain orders of magnitude better agreement between the computed and measured energy spectra. The presence and impact of Josephson harmonics has important implications for developing AlO$_x$-based quantum technologies including quantum computers and parametric amplifiers. As an example, we show that engineered Josephson harmonics can reduce the charge dispersion and the associated errors in transmon qubits by an order of magnitude, while preserving their anharmonicity. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2302_09192 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Observation of Josephson Harmonics in Tunnel Junctions Willsch, Dennis Rieger, Dennis Winkel, Patrick Willsch, Madita Dickel, Christian Krause, Jonas Ando, Yoichi Lescanne, Raphaël Leghtas, Zaki Bronn, Nicholas T. Deb, Pratiti Lanes, Olivia Minev, Zlatko K. Dennig, Benedikt Geisert, Simon Günzler, Simon Ihssen, Sören Paluch, Patrick Reisinger, Thomas Hanna, Roudy Bae, Jin Hee Schüffelgen, Peter Grützmacher, Detlev Buimaga-Iarinca, Luiza Morari, Cristian Wernsdorfer, Wolfgang DiVincenzo, David P. Michielsen, Kristel Catelani, Gianluigi Pop, Ioan M. Quantum Physics Superconductivity Approaches to developing large-scale superconducting quantum processors must cope with the numerous microscopic degrees of freedom that are ubiquitous in solid-state devices. State-of-the-art superconducting qubits employ aluminum oxide (AlO$_x$) tunnel Josephson junctions as the sources of nonlinearity necessary to perform quantum operations. Analyses of these junctions typically assume an idealized, purely sinusoidal current-phase relation. However, this relation is only expected to hold in the limit of vanishingly low-transparency channels in the AlO$_x$ barrier. Here we show that the standard current-phase relation fails to accurately describe the energy spectra of transmon artificial atoms across various samples and laboratories. Instead, a mesoscopic model of tunneling through an inhomogeneous AlO$_x$ barrier predicts percent-level contributions from higher Josephson harmonics. By including these in the transmon Hamiltonian, we obtain orders of magnitude better agreement between the computed and measured energy spectra. The presence and impact of Josephson harmonics has important implications for developing AlO$_x$-based quantum technologies including quantum computers and parametric amplifiers. As an example, we show that engineered Josephson harmonics can reduce the charge dispersion and the associated errors in transmon qubits by an order of magnitude, while preserving their anharmonicity. |
| title | Observation of Josephson Harmonics in Tunnel Junctions |
| topic | Quantum Physics Superconductivity |
| url | https://arxiv.org/abs/2302.09192 |