Gao Ran, Wu Feng, Sun Hantao, Chen Jianjun, Deng Hao, Ma Xizheng, Miao Xiaohe, Song Zhijun, Wan Xin, Wang Fei, Xia Tian, Ying Make, Zhang Chao, Shi Yaoyun, Zhao Hui-Hai, Deng Chunqing
Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area, Shenzhen, China.
Z-Axis Quantum, Hangzhou, China.
Nat Commun. 2025 Apr 16;16(1):3620. doi: 10.1038/s41467-025-58745-y.
Introducing disorder in the superconducting materials has been considered promising to enhance the electromagnetic impedance and realize noise-resilient superconducting qubits. Despite a number of pioneering implementations, the understanding of the correlation between the material disorder and the qubit coherence is still developing. Here, we demonstrate a systematic characterization of fluxonium qubits with the superinductors made by spinodal titanium-aluminum-nitride with varied disorder. From qubit noise spectroscopy, the flux noise and the dielectric loss are extracted as a measure of the coherence properties. Our results reveal that the 1/f flux noise dominates the qubit decoherence around the flux-frustration point, strongly correlated with the material disorder; while the dielectric loss are largely similar under a wide range of material properties. From the flux-noise amplitudes, the areal density (σ) of the phenomenological spin defects and material disorder are found to be approximately correlated by , or effectively . This work has provided new insights on the origin of decoherence channels beyond surface defects and within the superconductors, and could serve as a useful guideline for material design and optimization.
在超导材料中引入无序性被认为是提高电磁阻抗和实现抗噪声超导量子比特的有效途径。尽管已经有了许多开创性的实验，但对于材料无序性与量子比特相干性之间的关联的理解仍在不断发展。在此，我们展示了对由具有不同无序度的旋节线钛铝氮制成的超电感的磁通量子比特进行系统表征。通过量子比特噪声光谱，提取了磁通噪声和介电损耗作为相干特性的度量。我们的结果表明，在磁通受挫点附近，1/f磁通噪声主导了量子比特退相干，与材料无序性密切相关；而在广泛的材料特性范围内，介电损耗基本相似。从磁通噪声幅度来看，现象学自旋缺陷的面密度(σ)与材料无序性大致通过 相关，或有效通过 相关。这项工作为超导体内退相干通道的起源提供了新的见解，超越了表面缺陷，可为材料设计和优化提供有用的指导。
