Hybrid Josephson Rhombus: A Superconducting Element with Tailored Current-Phase Relation

作     者：L. Banszerus C. W. Andersson W. Marshall T. Lindemann M. J. Manfra C. M. Marcus S. Vaitiekėnas 

作者机构：Center for Quantum Devices Niels Bohr Institute University of Copenhagen 2100 Copenhagen Denmark Department of Physics University of Washington Seattle Washington 98195 USA Department of Physics and Astronomy Purdue University West Lafayette Indiana 47907 USA Birck Nanotechnology Center Purdue University West Lafayette Indiana 47907 USA School of Electrical and Computer Engineering Purdue University West Lafayette Indiana 47907 USA School of Materials Engineering Purdue University West Lafayette Indiana 47907 USA Materials Science and Engineering University of Washington Seattle Washington 98195 USA 

出 版 物：《Physical Review X》 (Phys. Rev. X)

年 卷 期：2025年第15卷第1期

页      面：011021-011021页

核心收录：

学科分类：07[理学] 0702[理学-物理学] 

基　　金：Danmarks Grundforskningsfond, DNRF Villum Fonden European Research Council, ERC, (856526) 

主　　题：Parametric amplifiers 

摘      要：Controlling the current-phase relation (CPR) of Josephson elements is essential for tailoring the eigenstates of superconducting qubits, tuning the properties of parametric amplifiers, and designing nonreciprocal superconducting devices. Here, we introduce the hybrid Josephson rhombus, a highly tunable superconducting circuit containing four semiconductor-superconductor hybrid Josephson junctions embedded in a loop. Combining magnetic frustration with gate-voltage-controlled tuning of individual Josephson couplings provides deterministic control of the harmonic content of the rhombus CPR. We show that, for balanced Josephson couplings at full frustration, the hybrid rhombus displays a π-periodic cos(2φ) potential, indicating coherent charge-4e transport. Tuning away from the balanced configuration, we observe a superconducting diode effect with efficiency exceeding 25%. These results showcase the potential of hybrid Josephson rhombi as fundamental building blocks for noise-resilient qubits and quantum devices with custom transport properties.